Duck
From Wikipedia, the free encyclopedia
This article is about the bird. For duck as a food, see Duck (food). For other meanings, see Duck (disambiguation).
"Duckling" redirects here. For other uses, see Duckling (disambiguation).
| Ducks | |
|---|---|
 | |
| Bufflehead | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Anseriformes |
| Family: | Anatidae |
| See text. | |
Ducks are sometimes confused with several types of unrelated water birds with similar forms, such as loons or divers, grebes, gallinules, and coots.
Contents
[hide]Etymology
This word replaced Old English ened/ænid "duck", possibly to avoid confusion with other Old English words, like ende "end" with similar forms. Other Germanic languages still have similar words for "duck", for example, Dutch eend "duck" and German Ente "duck". The word ened/ænid was inherited from Proto-Indo-European; compare: Latin anas "duck", Lithuanian ántis "duck", Ancient Greek nēssa/nētta (νῆσσα, νῆττα) "duck", and Sanskrit ātí "water bird", among others.
A duckling is a young duck in downy plumage[1] or baby duck;[2] but in the food trade young adult ducks ready for roasting are sometimes labelled "duckling".[citation needed]
A male duck is called a drake and the female duck is called a duck or hen.[citation needed]
Morphology
The drakes of northern species often have extravagant plumage, but that is moulted in summer to give a more female-like appearance, the "eclipse" plumage. Southern resident species typically show less sexual dimorphism, although there are exceptions like the Paradise Shelduck of New Zealand which is both strikingly sexually dimorphic and where the female's plumage is brighter than that of the male. The plumage of juvenile birds generally resembles that of the female.
Behaviour
Feeding
Diving ducks and sea ducks forage deep underwater. To be able to submerge more easily, the diving ducks are heavier than dabbling ducks, and therefore have more difficulty taking off to fly.
Dabbling ducks feed on the surface of water or on land, or as deep as they can reach by up-ending without completely submerging.[3] Along the edge of the beak there is a comb-like structure called a pecten. This strains the water squirting from the side of the beak and traps any food. The pecten is also used to preen feathers and to hold slippery food items.
A few specialized species such as the mergansers are adapted to catch and swallow large fish.
The others have the characteristic wide flat beak adapted to dredging-type jobs such as pulling up waterweed, pulling worms and small molluscs out of mud, searching for insect larvae, and bulk jobs such as dredging out, holding, turning headfirst, and swallowing a squirming frog. To avoid injury when digging into sediment it has no cere, but the nostrils come out through hard horn.
Breeding
The ducks are generally monogamous, although these bonds generally last a single year only. Larger species and the more sedentary species (like fast river specialists) tend to have pair-bonds that last numerous years. Most duck species breed once a year, choosing to do so in favourable conditions (spring/summer or wet seasons). Ducks also tend to make a nest before breeding. Although mother ducks are very caring and protective of their young, they are not above abandoning some of their ducklings if they are physically stuck in an area they cannot get out of or are not prospering due to genetic defects or sickness brought about by hypothermia, starvation, or disease. Ducklings can also be orphaned by inconsistent, late hatching where a few eggs hatch long after the mother has abandoned the nest.[citation needed]Communication
Females of most dabbling ducks[citation needed] make the classic "quack" sound, but despite widespread misconceptions, most species of duck do not "quack". In general, ducks make a wide range of calls, ranging from whistles, cooing, yodels and grunts. For example, the scaup – which are diving ducks – make a noise like "scaup" (hence their name). Calls may be loud displaying calls or quieter contact calls.A common urban legend claims that duck quacks do not echo; however, this has been shown to be false. This myth was first debunked by the Acoustics Research Centre at the University of Salford in 2003 as part of the British Association's Festival of Science.[4] It was also debunked in one of the earlier episodes of the popular Discovery Channel television show MythBusters.[5]
Ecology
Distribution and habitat
See also: List of Anseriformes by population
The ducks have a cosmopolitan distribution occurring across most of the world except for Antarctica. A number of species manage to live on sub-Antarctic islands like South Georgia and the Auckland Islands. Numerous ducks have managed to establish themselves on oceanic islands such as Hawaii, New Zealand and Kerguelen, although many of these species and populations are threatened or have become extinct.Some duck species, mainly those breeding in the temperate and Arctic Northern Hemisphere, are migratory; those in the tropics, however, are generally not. Some ducks, particularly in Australia where rainfall is patchy and erratic, are nomadic, seeking out the temporary lakes and pools that form after localised heavy rain.[citation needed]
Predators
Worldwide, ducks have many predators. Ducklings are particularly vulnerable, since their inability to fly makes them easy prey not only for predatory birds but also large fish like pike, crocodilians, and other aquatic hunters, including fish-eating birds such as herons. Ducks' nests are raided by land-based predators, and brooding females may be caught unaware on the nest by mammals, such as foxes, or large birds, such as hawks or eagles.
Adult ducks are fast fliers, but may be caught on the water by large aquatic predators including big fish such as the North American muskie and the European pike. In flight, ducks are safe from all but a few predators such as humans and the Peregrine Falcon, which regularly uses its speed and strength to catch ducks.
Relationship with humans
Domestication
Main article: Domestic duck
Ducks have many economic uses, being farmed for their meat, eggs, feathers, (particularly their down). They are also kept and bred by aviculturists and often displayed in zoos. Almost all the varieties of domestic ducks are descended from the Mallard (Anas platyrhynchos), apart from the Muscovy Duck (Cairina moschata).[6][7]In many areas, wild ducks of various species (including ducks farmed and released into the wild) are hunted for food or sport, by shooting, or formerly by decoys. Because an idle floating duck or a duck squatting on land cannot react to fly or move quickly, "a sitting duck" has come to mean "an easy target".
Cultural references
See also
References
- Jump up ^ "Duckling". The American Heritage Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company. 2006. Retrieved 05-01-2008.
- Jump up ^ "Duckling". Kernerman English Multilingual Dictionary (Beta Version). K. Dictionaries Ltd. 2000-2006. Retrieved 05-01-2008.
- Jump up ^ Ogden, Evans. "Dabbling Ducks". CWE. Retrieved 2006-11-02.
- Jump up ^ Amos, Jonathan (2003-09-08). "Sound science is quackers". BBC News. Retrieved 2006-11-02.
- Jump up ^ "Mythbusters Episode 8". 12 December 2003.
- Jump up ^ "Anas platyrhynchos, Domestic Duck; DigiMorph Staff - The University of Texas at Austin". Digimorph.org. Retrieved 2012-12-23.
- Jump up ^ Sy Montgomery. "Mallard; Encyclopædia Britannica". Britannica.com. Retrieved 2012-12-23.
- Jump up ^ World's funniest joke revealed New Scientist, 3 October 2002
- Jump up ^ http://www.imdb.com/title/tt0091225/
External links
 | Look up duck in Wiktionary, the free dictionary. |
 | Wikimedia Commons has media related to Duck. |
 | Wikibooks Cookbook has a recipe/module on |
- Media related to the Anatidae on the Internet Bird Collection
- list of books (useful looking abstracts)
- Ducks on postage stamps
- Ducks at a Distance, by Rob Hines at Project Gutenberg - A modern illustrated guide to identification of US waterfowl.
- Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.Chicken
From Wikipedia, the free encyclopedia"Gallus gallus domesticus" redirects here. For other subspecies, see Red Junglefowl."Chooks" redirects here. For other uses, see Chooks (disambiguation).This article is about the animal. For chicken as human food, see Chicken (food). For other uses, see Chicken (disambiguation).The chicken (Gallus gallus domesticus) is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals with a population of more than 24 billion in 2003,[1] there are more chickens in the world than any other species of bird. Humans keep chickens primarily as a source of food, consuming both their meat and their eggs.Chicken A rooster (left) and hen (right) Conservation status DomesticatedScientific classification Kingdom: Animalia Phylum: Chordata Class: Aves Order: Galliformes Family: Phasianidae Subfamily: Phasianinae Genus: Gallus Species: G. gallus Subspecies: G. g. domesticus Trinomial name Gallus gallus domesticus
(Linnaeus, 1758)
The traditional poultry farming view of the domestication of the chicken is stated in Encyclopædia Britannica (2007): "Humans first domesticated chickens of Indian origin for the purpose of cockfighting in Asia, Africa, and Europe. Very little formal attention was given to egg or meat production... "[2] Recent genetic studies have pointed to multiple maternal origins in Southeast, East, and South Asia, but with the clade found in the Americas, Europe, the Middle East and Africa originating in the Indian subcontinent. From India, the domesticated chicken was imported to Lydia in western Asia Minor, and to Greece by the fifth century BC.[3] Fowl had been known in Egypt since the 18th Dynasty, with the "bird that gives birth every day" having come to Egypt from the land between Syria and Shinar, Babylonia, according to the annals of Tutmose III.[4][5]
Contents
[hide]Terminology
In the UK and Ireland adult male chickens over the age of 12 months are primarily known as cocks, whereas in America, Australia and Canada they are more commonly called roosters. Males less than 1 year old are cockerels.[6] Castrated roosters are called capons (surgical and chemical castration are now illegal in some parts of the world). Females over a year old are known as hens and younger females as pullets[7] although in the egg-laying industry, a pullet becomes a hen when she begins to lay eggs at 16 to 20 weeks of age. In Australia and New Zealand (also sometimes in Britain), there is a generic term chook /ˈtʃʊk/ to describe all ages and both sexes.[8] The young are called chicks and the meat is called chicken.
"Chicken" originally referred to chicks, not the species itself. The species as a whole was then called domestic fowl, or just fowl. This use of "chicken" survives in the phrase "Hen and Chickens", sometimes used as a British public house or theatre name, and to name groups of one large and many small rocks or islands in the sea (see for example Hen and Chicken Islands).
In the Deep South of the United States chickens are also referred to by the slang term yardbird.[9]
General biology and habitat
Chickens are omnivores.[10] In the wild, they often scratch at the soil to search for seeds, insects and even larger animals such as lizards or young mice.[11]
Chickens may live for five to ten years, depending on the breed.[12] The world's oldest chicken, a hen, died of heart failure at the age of 16 according to the Guinness Book of World Records.[13]
Roosters can usually be differentiated from hens by their striking plumage of long flowing tails and shiny, pointed feathers on their necks (hackles) and backs (saddle) which are typically of brighter, bolder colours than those of females of the same breed. However, in some breeds, such as the Sebright, the rooster has only slightly pointed neck feathers, the same colour as the hen's. The identification can be made by looking at the comb, or eventually from the development of spurs on the male's legs (in a few breeds and in certain hybrids, the male and female chicks may be differentiated by colour). Adult chickens have a fleshy crest on their heads called a comb, or cockscomb, and hanging flaps of skin either side under their beaks called wattles. Collectively, these and other fleshy protuberances on the head and throat are called caruncles. Both the adult male and female have wattles and combs, but in most breeds these are more prominent in males. A muff or beard is a mutation found in several chicken breeds which causes extra feathering under the chicken's face, giving the appearance of a beard.
Domestic chickens are not capable of long distance flight, although lighter birds are generally capable of flying for short distances, such as over fences or into trees (where they would naturally roost). Chickens may occasionally fly briefly to explore their surroundings, but generally do so only to flee perceived danger.Wild Red Junglefowl
Behaviour
Social behaviour
Chickens are gregarious birds and live together in flocks. They have a communal approach to the incubation of eggs and raising of young. Individual chickens in a flock will dominate others, establishing a "pecking order", with dominant individuals having priority for food access and nesting locations. Removing hens or roosters from a flock causes a temporary disruption to this social order until a new pecking order is established. Adding hens, especially younger birds, to an existing flock can lead to fighting and injury.[14] When a rooster finds food, he may call other chickens to eat first. He does this by clucking in a high pitch as well as picking up and dropping the food. This behaviour may also be observed in mother hens to call their chicks and encourage them to eat.
Roosters crowing (a loud and sometimes shrill call) is a territorial signal to other roosters. However, crowing may also result from sudden disturbances within their surroundings. Hens cluck loudly after laying an egg, and also to call their chicks. Chickens also give a low "warning call" when they think they see a predator approaching.
Courtship
To initiate courting, some roosters may dance in a circle around or near a hen ("a circle dance"), often lowering his wing which is closest to the hen.[15] The dance triggers a response in the hen[15] and when she responds to his "call", the rooster may mount the hen and proceed with the mating.
Nesting and laying behaviour
Hens will often try to lay in nests that already contain eggs and have been known to move eggs from neighbouring nests into their own. The result of this behaviour is that a flock will use only a few preferred locations, rather than having a different nest for every bird. Hens will often express a preference to lay in the same location. It is not unknown for two (or more) hens to try to share the same nest at the same time. If the nest is small, or one of the hens is particularly determined, this may result in chickens trying to lay on top of each other. There is evidence that individual hens prefer to be either solitary or gregarious nesters.[16] Some farmers use fake eggs made from plastic or stone (or golf balls) to encourage hens to lay in a particular location.
Broodiness and early life
Under natural conditions, most birds lay only until a clutch is complete, and they will then incubate all the eggs. Many domestic hens will also do this–and are then said to "go broody". The broody hen will stop laying and instead will focus on the incubation of the eggs (a full clutch is usually about 12 eggs). She will "sit" or "set" on the nest, protesting or pecking in defense if disturbed or removed, and she will rarely leave the nest to eat, drink, or dust-bathe. While brooding, the hen maintains the nest at a constant temperature and humidity, as well as turning the eggs regularly during the first part of the incubation. To stimulate broodiness, an owner may place many artificial eggs in the nest, or to stop it they may place the hen in an elevated cage with an open wire floor.
At the end of the incubation period (about 21 days),[15] the eggs, if fertile, will hatch. Development of the egg starts only when incubation begins, so they all hatch within a day or two of each other, despite perhaps being laid over a period of two weeks or so. Before hatching, the hen can hear the chicks peeping inside the eggs, and will gently cluck to stimulate them to break out of their shells. The chick begins by "pipping"; pecking a breathing hole with its egg tooth towards the blunt end of the egg, usually on the upper side. The chick will then rest for some hours, absorbing the remaining egg yolk and withdrawing the blood supply from the membrane beneath the shell (used earlier for breathing through the shell). It then enlarges the hole, gradually turning round as it goes, and eventually severing the blunt end of the shell completely to make a lid. It crawls out of the remaining shell, and its wet down dries out in the warmth of the nest.
The hen will usually stay on the nest for about two days after the first egg hatches, and during this time the newly hatched chicks live off the egg yolk they absorb just before hatching. Any eggs not fertilized by a rooster will not hatch, and the hen eventually loses interest in these and leaves the nest. After hatching, the hen fiercely guards the chicks, and will brood them when necessary to keep them warm, at first often returning to the nest at night. She leads them to food and water; she will call them to edible items, but seldom feeds them directly. She continues to care for them until they are several weeks old, when she will gradually lose interest and eventually start to lay again.A day-old chick
Modern egg-laying breeds rarely go broody, and those that do often stop part-way through the incubation. However, some "utility" (general purpose) breeds, such as the Cochin, Cornish and Silkie, do regularly go broody, and they make excellent mothers, not only for chicken eggs but also for those of other species—even those with much smaller or larger eggs and different incubation periods, such as quail, pheasants, turkeys or geese. Chicken eggs can also be hatched under a broody duck, with varied success.
Artificial incubation
Incubation can successfully occur artificially in machines that provide the correct, controlled environment for the developing chick.[17][18][19][20] The average incubation period for chickens is 21 days but may depend on the temperature and humidity in the incubator. Temperature regulation is the most critical factor for a successful hatch. Variations of more than 1 °C (1.8 °F) from the optimum temperature of 37.5 °C (99.5 °F) will reduce hatch rates. Humidity is also important because the rate at which eggs lose water by evaporation depends on the ambient relative humidity. Evaporation can be assessed by candling, to view the size of the air sac, or by measuring weight loss. Relative humidity should be increased to around 70% in the last three days of incubation to keep the membrane around the hatching chick from drying out after the chick cracks the shell. Lower humidity is usual in the first 18 days to ensure adequate evaporation. The position of the eggs in the incubator can also influence hatch rates. For best results, eggs should be placed with the pointed ends down and turned regularly (at least three times per day) until one to three days before hatching. If the eggs aren't turned, the embryo inside may stick to the shell and may hatch with physical defects. Adequate ventilation is necessary to provide the embryo with oxygen. Older eggs require increased ventilation.An egg incubator
Many commercial incubators are industrial-sized with shelves holding tens of thousands of eggs at a time, with rotation of the eggs a fully automated process. Home incubators are boxes holding from 6 to 75 eggs; they are usually electrically powered, but in the past some were heated with an oil or paraffin lamp.
Embryology
In 2006, scientists researching the ancestry of birds "turned on" a chicken recessive gene, talpid2, and found that the embryo jaws initiated formation of teeth, like those found in ancient bird fossils. John Fallon, the overseer of the project, stated that chickens have "...retained the ability to make teeth, under certain conditions... ."[21]Skull of a three-week-old chicken. Here the opisthotic bone appears in the occipital region, as in the adult Chelonian. bo = Basi-occipital, bt = Basi-temporal, eo = Opisthotic, f = Frontal, fm = Foramen magnum, fo = Fontanella, oc = Occipital condyle, op = Opisthotic, p = Parietal, pf = Post-frontal, sc = Sinus canal in supra-occipital, so = Supra-occpital, sq = Squamosal, 8 = Exit of vagus nerve.
Breeding
Origins
The domestic chicken is descended primarily from the Red Junglefowl (Gallus gallus) and is scientifically classified as the same species.[22] As such it can and does freely interbreed with populations of red jungle fowl.[22] Recent genetic analysis has revealed that at least the gene for yellow skin was incorporated into domestic birds through hybridization with the Grey Junglefowl (G. sonneratii).[23] The traditional poultry farming view is stated in Encyclopædia Britannica (2007): "Humans first domesticated chickens of Indian origin for the purpose of cockfighting in Asia, Africa, and Europe. Very little formal attention was given to egg or meat production... "[2] In the last decade there have been a number of genetic studies. According to one study, a single domestication event occurring in the region of modern Thailand created the modern chicken with minor transitions separating the modern breeds.[24] However, that study was later found to be based on incomplete data, and recent studies point to multiple maternal origins, with the clade found in the Americas, Europe, Middle East, and Africa, originating from the Indian subcontinent, where a large number of unique haplotypes occur.[25][26] It is postulated that the Jungle Fowl, known as the "bamboo fowl" in many Southeast Asian languages, is a special pheasant well adapted to take advantage of the large amounts of fruits that are produce during the end of the 50 year bamboo seeding cycle to boost its own reproduction.[27] According to Daniel H. Janzen of the University of Pennsylvania, in domesticating the chicken, humans took advantage of this prolific reproduction of the jungle fowl when exposed to large amount of food. [28]
It has been claimed (based on paleoclimatic assumptions) that chickens were domesticated in Southern China in 6000 BC.[29] However, according to a recent study,[30] "it is not known whether these birds made much contribution to the modern domestic fowl. Chickens from the Harappan culture of the Indus Valley (2500-2100 BC), in what today is Pakistan, may have been the main source of diffusion throughout the world." A northern road spread chicken to the Tarim basin of central Asia. The chicken reached Europe (Romania, Turkey, Greece, Ukraine) about 3000 BC.[31] Introduction into Western Europe came far later, about the 1st millennium BC. Phoenicians spread chickens along the Mediterranean coasts, to Iberia. Breeding increased under the Roman Empire, and was reduced in the Middle Ages.[31] Middle East traces of chicken go back to a little earlier than 2000 BC, in Syria; chicken went southward only in the 1st millennium BC. The chicken reached Egypt for purposes of cock fighting about 1400 BC, and became widely bred only in Ptolemaic Egypt (about 300 BC).[31] Little is known about the chicken's introduction into Africa. Three possible ways of introduction in about the early first millennium AD could have been through the Egyptian Nile Valley, the East Africa Roman-Greek or Indian trade, or from Carthage and the Berbers, across the Sahara. The earliest known remains are from Mali, Nubia, East Coast, and South Africa and date back to the middle of the first millennium AD.[31] Domestic chicken in the Americas before Western conquest is still an ongoing discussion, but blue-egged chicken, found only in the Americas and Asia, suggest an Asian origin for early American chickens.[31]
A lack of data from Thailand, Russia, the Indian subcontinent, Southeast Asia and Sub-Saharan Africa makes it difficult to lay out a clear map of the spread of chickens in these areas; better description and genetic analysis of local breeds threatened by extinction may also help with research into this area.[31]
South America
An unusual variety of chicken that has its origins in South America is the araucana, bred in southern Chile by Mapuche people. Araucanas, some of which are tailless and some of which have tufts of feathers around their ears, lay blue-green eggs. It has long been suggested that they pre-date the arrival of European chickens brought by the Spanish and are evidence of pre-Columbian trans-Pacific contacts between Asian or Pacific Oceanic peoples, particularly the Polynesians and South America. In 2007, an international team of researchers reported the results of analysis of chicken bones found on the Arauco Peninsula in south-central Chile. Radiocarbon dating suggested that the chickens were Pre-Columbian, and DNA analysis showed that they were related to prehistoric populations of chickens in Polynesia.[32] These results appeared to confirm that the chickens came from Polynesia and that there were transpacific contacts between Polynesia and South America before Columbus's arrival in the Americas.[33]
However, a later report looking at the same specimens concluded:
A published, apparently pre-Columbian, Chilean specimen and six pre-European Polynesian specimens also cluster with the same European/Indian subcontinental/Southeast Asian sequences, providing no support for a Polynesian introduction of chickens to South America. In contrast, sequences from two archaeological sites on Easter Island group with an uncommon haplogroup from Indonesia, Japan, and China and may represent a genetic signature of an early Polynesian dispersal. Modeling of the potential marine carbon contribution to the Chilean archaeological specimen casts further doubt on claims for pre-Columbian chickens, and definitive proof will require further analyses of ancient DNA sequences and radiocarbon and stable isotope data from archaeological excavations within both Chile and Polynesia.[34]
As pets
Main article: Chickens as petsChickens are sometimes kept as pets and can be tamed by hand feeding, but roosters can sometimes become aggressive and noisy, although aggression can be curbed with proper handling. Some have advised against keeping them around very young children. Certain breeds, however, such as silkies and many bantam varieties are generally docile and are often recommended as good pets around children with disabilities.[35] Some people find chickens' behaviour entertaining and educational.[36]
Diseases and ailments
Chickens are susceptible to several parasites, including lice, mites, ticks, fleas, and intestinal worms, as well as other diseases. Despite the name, they are not affected by chickenpox, which is generally restricted to humans.[37]
Some of the common diseases that affect chickens are shown below:
Name Common name Caused by Aspergillosis fungi Avian influenza bird flu virus Histomoniasis Blackhead disease protozoal parasite Botulism toxin Cage Layer Fatigue mineral deficiencies, lack of exercise Campylobacteriosis tissue injury in the gut Coccidiosis parasites Colds virus Crop Bound improper feeding Dermanyssus gallinae Red mite parasite Egg bound oversized egg Erysipelas bacteria Fatty Liver Hemorrhagic Syndrome high-energy food Fowl Cholera bacteria Fowl pox virus Fowl Typhoid bacteria Gallid herpesvirus 1
or Infectious Laryngotracheitisvirus Gapeworm Syngamus trachea worms Infectious Bronchitis virus Infectious Bursal Disease Gumboro virus Infectious Coryza bacteria Lymphoid leukosis Avian leukosis virus Marek's disease virus Moniliasis Yeast Infection
or Thrushfungi Mycoplasmas bacteria-like organisms Newcastle disease virus Necrotic Enteritis bacteria Omphalitis Mushy chick disease umbilical cord stump Peritonitis[38] Infection in abdomen from egg yolk Prolapse Psittacosis bacteria Pullorum Salmonella bacteria Scaly leg parasites Squamous cell carcinoma cancer Tibial dyschondroplasia speed growing Toxoplasmosis protozoal parasite Ulcerative Enteritis bacteria Ulcerative pododermatitis Bumblefoot bacteria In religion and mythology
Since antiquity chickens have been, and still are, a sacred animal in some cultures[39] and deeply embedded within various belief systems and religious worship. The term "Persian bird" for the cock would appear to been given by the Greeks after Persian contact "because of his great importance and his religious use among the Persians".[40]
In Indonesia the chicken has great significance during the Hindu cremation ceremony. A chicken is considered a channel for evil spirits which may be present during the ceremony. A chicken is tethered by the leg and kept present at the ceremony for its duration to ensure that any evil spirits present during the ceremony go into the chicken and not the family members present. The chicken is then taken home and returns to its normal life.
In ancient Greece, the chicken was not normally used for sacrifices, perhaps because it was still considered an exotic animal. Because of its valor, the cock is found as an attribute of Ares, Heracles, and Athena. The alleged last words of Socrates as he died from hemlock poisoning, as recounted by Plato, were "Crito, I owe a cock to Asclepius; will you remember to pay the debt?", signifying that death was a cure for the illness of life.
The Greeks believed that even lions were afraid of cocks. Several of Aesop's Fables reference this belief.
In the New Testament, Jesus prophesied the betrayal by Peter: "Jesus answered, 'I tell you, Peter, before the rooster crows today, you will deny three times that you know me.'" (Luke 22:34) Thus it happened (Luke 22:61), and Peter cried bitterly. This made the cock a symbol for both vigilance and betrayal. The rooster(cock) serves as a tangible vessel of Christ for some as in the gospel of Matthew, Mark and Luke in the New Testament with Christ speaking through the cock.[41] In the sixth century, Pope Gregory I declared the cock the emblem of Christianity[42] and another Papal enactment of the ninth century by Pope Nicholas I[39] ordered the figure of the cock to be placed on every church steeple.[43]
Earlier, Jesus compares himself to a mother hen when talking about Jerusalem: "O Jerusalem, Jerusalem, you who kill the prophets and stone those sent to you, how often I have longed to gather your children together, as a hen gathers her chicks under her wings, but you were not willing." (Matthew 23:37; also Luke 13:34).
In many Central European folk tales, the devil is believed to flee at the first crowing of a cock.
In traditional Jewish practice, a kosher animal is swung around the head and then slaughtered on the afternoon before Yom Kippur, the Day of Atonement, in a ritual called kapparos; it is now common practice to cradle the bird and move it around the head. A chicken or fish is typically used because it is commonly available (and small enough to hold). The sacrifice of the animal is to receive atonement, for the animal symbolically takes on all the person's sins in kapparos. The meat is then donated to the poor. A woman brings a hen for the ceremony, while a man brings a rooster. Although not actually a sacrifice in the biblical sense, the death of the animal reminds the penitent sinner that his or her life is in God's hands.
The Talmud speaks of learning "courtesy toward one's mate" from the rooster (Eruvin 100b). This might refer to the fact that when a rooster finds something good to eat, he calls his hens to eat first. The Talmud likewise provides us with the statement "Had the Torah not been given to us, we would have learned modesty from cats, honest toil from ants, chastity from doves and gallantry from cocks"[44] - (Jonathan ben Nappaha. Talmud: Erubin 100b), which may be further understood as to that of the gallantry of cocks being taken in the context of a religious instilling vessel of "a girt one of the loins"(Young's Literal Translation) that which is "stately in his stride" and "move with stately bearing" within the Book of Proverbs 30:29-31 as referenced by Michael V. Fox in his book Proverbs 10-31 where Saʻadiah ben Yosef Gaon(Saadia Gaon) identifies the definitive trait of "A cock girded about the loins" within Proverbs 30:31(Douay–Rheims Bible) as "the honesty of their behavior and their success",[45] identifying a spiritual purpose of a religious vessel within that religious instilling schema of purpose and use.
The chicken is one of the Zodiac symbols of the Chinese calendar. Also in Chinese religion, a cooked chicken as a religious offering is usually limited to ancestor veneration and worship of village deities. Vegetarian deities such as the Buddha are not one of the recipients of such offerings. Under some observations, an offering of chicken is presented with "serious" prayer (while roasted pork is offered during a joyous celebration). In Confucian Chinese Weddings, a chicken can be used as a substitute for one who is seriously ill or not available (e.g. sudden death) to attend the ceremony. A red silk scarf is placed on the chicken's head and a close relative of the absent bride/groom holds the chicken so the ceremony may proceed. However, this practice is rare today.
A cockatrice was supposed to have been born from an egg laid by a rooster, as well as killed by a Rooster's call.
In history
An early domestication of chickens in Southeast Asia is probable, since the word for domestic chicken (*manuk) is part of the reconstructed Proto-Austronesian language (see Austronesian languages). Chickens, together with dogs and pigs, were the domestic animals of the Lapita culture,[46] the first Neolithic culture of Oceania.[47]The Red Junglefowl
The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC.[48][49] The poet Cratinus (mid-5th century BC, according to the later Greek author Athenaeus) calls the chicken "the Persian alarm". In Aristophanes's comedy The Birds (414 BC) a chicken is called "the Median bird", which points to an introduction from the East. Pictures of chickens are found on Greek red figure and black-figure pottery.
In ancient Greece, chickens were still rare and were a rather prestigious food for symposia[citation needed]. Delos seems to have been a center of chicken breeding[citation needed].
The Romans used chickens for oracles, both when flying ("ex avibus", Augury) and when feeding ("auspicium ex tripudiis", Alectryomancy). The hen ("gallina") gave a favourable omen ("auspicium ratum"), when appearing from the left (Cic.,de Div. ii.26), like the crow and the owl.
For the oracle "ex tripudiis" according to Cicero (Cic. de Div. ii.34), any bird could be used in auspice, and shows at one point that any bird could perform the tripudium[50] but normally only chickens ("pulli") were consulted. The chickens were cared for by the pullarius, who opened their cage and fed them pulses or a special kind of soft cake when an augury was needed. If the chickens stayed in their cage, made noises ("occinerent"), beat their wings or flew away, the omen was bad; if they ate greedily, the omen was good.[51]
In 249 BC, the Roman general Publius Claudius Pulcher had his "sacred chickens" "[52] thrown overboard when they refused to feed before the battle of Drepana, saying "If they won't eat, perhaps they will drink." He promptly lost the battle against the Carthaginians and 93 Roman ships were sunk. Back in Rome, he was tried for impiety and heavily fined.
In 162 BC, the Lex Faunia forbade fattening hens to conserve grain rations.[53][54] To get around this, the Romans castrated roosters(capon), which resulted in a doubling of size[55] despite the law that was passed in Rome that forbade the consumption of fattened chickens. It was renewed a number of times, but does not seem to have been successful. Fattening chickens with bread soaked in milk was thought to give especially delicious results. The Roman gourmet Apicius offers 17 recipes for chicken, mainly boiled chicken with a sauce. All parts of the animal are used: the recipes include the stomach, liver, testicles and even the pygostyle (the fatty "tail" of the chicken where the tail feathers attach).
The Roman author Columella gives advice on chicken breeding in his eighth book of his treatise on agriculture[citation needed]. He identifies Tanagrian, Rhodic, Chalkidic and Median (commonly misidentified as Melian) breeds, which have an impressive appearance, a quarrelsome nature and were used for cockfighting by the Greeks. For farming, native (Roman) chickens are to be preferred, or a cross between native hens and Greek cocks. Dwarf chickens are nice to watch because of their size but have no other advantages.
According to Columella[citation needed], the ideal flock consists of 200 birds, which can be supervised by one person if someone is watching for stray animals. White chickens should be avoided as they are not very fertile and are easily caught by eagles or goshawks. One cock should be kept for five hens. In the case of Rhodian and Median cocks that are very heavy and therefore not much inclined to sex, only three hens are kept per cock. The hens of heavy fowls are not much inclined to brood; therefore their eggs are best hatched by normal hens. A hen can hatch no more than 15-23 eggs, depending on the time of year, and supervise no more than 30 hatchlings. Eggs that are long and pointed give more male, rounded eggs mainly female hatchlings[citation needed].
Columella also states that chicken coops should face southeast and lie adjacent to the kitchen, as smoke is beneficial for the animals and "poultry never thrive so well as in warmth and smoke".[56] Coops should consist of three rooms and possess a hearth. Dry dust or ash should be provided for dust-baths.
According to Columella[citation needed], chicken should be fed on barley groats, small chick-peas, millet and wheat bran, if they are cheap. Wheat itself should be avoided as it is harmful to the birds. Boiled ryegrass (Lolium sp.) and the leaves and seeds of alfalfa (Medicago sativa L.) can be used as well. Grape marc can be used, but only when the hens stop laying eggs, that is, about the middle of November; otherwise eggs are small and few. When feeding grape marc, it should be supplemented with some bran. Hens start to lay eggs after the winter solstice, in warm places around the first of January, in colder areas in the middle of February. Parboiled barley increases their fertility; this should be mixed with alfalfa leaves and seeds, or vetches or millet if alfalfa is not at hand. Free-ranging chickens should receive two cups of barley daily.
Columella[citation needed] advises farmers to slaughter hens that are older than three years, because they no longer produce sufficient eggs.
According to Aldrovandi: Capons were produced by burning "the hind part of the bowels, or loins or spurs"[57] with a hot iron. The wound was treated with potter's chalk.
For the use of poultry and eggs in the kitchens of ancient Rome see Roman eating and drinking.
Chickens were spread by Polynesian seafarers and reached Easter Island in the 12th century AD, where they were the only domestic animal, with the possible exception of the Polynesian Rat (Rattus exulans). They were housed in extremely solid chicken coops built from stone, which was first reported as such to Linton Palmer in 1868, who also "expressed his doubts about this".[58]
Farming
Main article: Poultry farmingMore than 50 billion chickens are reared annually as a source of food, for both their meat and their eggs.A free range rooster on a farm
The vast majority of poultry are raised using intensive farming techniques. According to the Worldwatch Institute, 74 percent of the world's poultry meat, and 68 percent of eggs are produced this way. One alternative to intensive poultry farming is free range farming.
Friction between these two main methods has led to long term issues of ethical consumerism. Opponents of intensive farming argue that it harms the environment, creates human health risks and is inhumane. Advocates of intensive farming say that their highly efficient systems save land and food resources due to increased productivity, stating that the animals are looked after in state-of-the-art environmentally controlled facilities.
In part due to the conditions on intensive poultry farms and recent recalls of large quantities of eggs, there is a growing movement for small scale micro-flocks or 'backyard chickens'. This involves keeping small numbers of hens (usually no more than a dozen), in suburban or urban residential areas to control bugs, utilize chicken waste as fertilizer in small gardens, and of course for the high-quality eggs and meat that are produced.
Reared for meat
Main article: BroilerChickens farmed for meat are called broiler chickens. Chickens will naturally live for 6 or more years, but broiler chickens typically take less than 6 weeks to reach slaughter size.[59] A free range or organic meat chicken will usually be slaughtered at about 14 weeks of age.
Reared for eggs
Chickens farmed for eggs are called egg-laying hens. In total, the UK alone consumes over 29 million eggs per day. Some hen breeds can produce over 300 eggs per year, with "the highest authenticated rate of egg laying being 371 eggs in 364 days".[60] After 12 months of laying, the commercial hen's egg-laying ability starts to decline to the point where the flock is unviable. Hens, particularly from battery cage systems, are sometimes infirm, have lost a significant amount of their feathers, and their life expectancy has been reduced from around 7 years to less than 2 years.[61] In the UK and Europe, laying hens are then slaughtered and used in processed foods, or sold as "soup hens".[61] In some other countries, flocks are sometimes force moulted, rather than being slaughtered, to reinvigorate egg-laying. This involves complete withdrawal of food (and sometimes water) for 7–14 days[62] or sufficiently long to cause a body weight loss of 25 to 35%,[63] or up to 28 days under experimental conditions[64] which presumably reflect farming practice[original research?]. This stimulates the hen to lose her feathers, but also reinvigorates egg-production. Some flocks may be force moulted several times. In 2003, more than 75% of all flocks were moulted in the US.[65]
As food
Main article: Chicken (food)The meat of the chicken, also called "chicken", is a type of poultry meat. Because of its relatively low cost, chicken is one of the most used meats in the world. Nearly all parts of the bird can be used for food, and the meat can be cooked in many different ways. Popular chicken dishes include roasted chicken, fried chicken, chicken soup, Buffalo wings, tandoori chicken, butter chicken, and chicken rice. Chicken is also a staple of many fast food restaurants.Roasted chicken.
Eggs
Main articles: Egg (food) and List of egg dishesIn 2000, there were 50.4 million tons of eggs produced in the world (Executive guide to world poultry trends, 2001)[66] and an estimated 53.4 million tons of table eggs were produced during 2002.[67] In 2009, an estimated 62.1 million metric tons of eggs were produced worldwide from a total laying flock of approximately 6.4 billion hens.[68]A fried chicken egg, "sunny side up".
Chicken eggs are widely used in many types of dishes, both sweet and savory, including many baked goods. Eggs can be scrambled, fried, hard-boiled, soft-boiled, pickled, and poached. The albumen, or egg white, contains protein but little or no fat, and can be used in cooking separately from the yolk. Egg whites may be aerated or whipped to a light, fluffy consistency and are often used in desserts such as meringues and mousse. Ground egg shells are sometimes used as a food additive to deliver calcium. Hens do not need a male to produce eggs, only to fertilize them. A flock containing only females will still produce eggs, however the eggs will all be infertile.
See also
Chicks before their first outing- Abnormal behaviour of birds in captivity
- Bantam (poultry)
- British Hen Welfare Trust, a UK charity for laying hens
- Chickens as pets
- Chicken eyeglasses
- Chicken fat
- Chicken hypnotism
- Chicken or the egg
- Chickenpox
- Chook raffle - a type of raffle where the prize is a chicken.
- Feral chicken
- Gamebird hybrids - hybrids between chickens, peafowl, guineafowl and pheasants
- List of chicken breeds
- Poultry
- Rubber chicken
- Symbolic chickens
- Tastes like chicken
- Unihemispheric slow-wave sleep
- "Why did the chicken cross the road?"
References
- Jump up ^ according to Firefly Encyclopedia of Birds, Ed. Perrins, Christopher. Buffalo, N.Y.: Firefly Books, Ltd., 2003.
- ^ Jump up to: a b Garrigus, W. P. (2007), "Poultry Farming". Encyclopædia Britannica.
- Jump up ^ Maguelonne Toussaint-Samat, (Anthea Bell, translator) The History of Food, Ch. 11 "The History of Poultry", revised ed. 2009, p. 306.
- Jump up ^ Howard Carter, "An Ostracon Depicting a Red Jungle-Fowl (The Earliest Known Drawing of the Domestic Cock)" The Journal of Egyptian Archaeology, 9.1/2 (April 1923), pp. 1-4.
- Jump up ^ Pritchard, "The Asiatic Campaigns of Thutmose III" Ancient Near East Texts related to the Old Testament, p240.
- Jump up ^ "Cockerel - definitions from Dictionary.com". Dictionary.reference.com. Retrieved 2010-08-29.
- Jump up ^ "Pullet - definitions from Dictionary.com". Dictionary.reference.com. Retrieved 2010-08-29.
- Jump up ^ "Definition of "chook" in Encarta. The vernacular use is said to be offensive in this dictionary but it may also be used as a term of jocular familiarity". Archived from the original on 2009-10-31.
- Jump up ^ Berhardt, Clyde E. B. (1986). I Remember: Eighty Years of Black Entertainment, Big Bands. Philadelphia: University of Pennsylvania Press. p. 153. ISBN 978-0-8122-8018-0. OCLC 12805260.
- Jump up ^ "Info on Chicken Care". ideas4pets. 2003. Retrieved 2008-08-13.
- Jump up ^ Gerard P.Worrell AKA "Farmer Jerry". "Frequently asked questions about chickens & eggs". Ferry Landing Farm & Apiary. Retrieved 2008-08-13.
- Jump up ^ "The Poultry Guide - A to Z and FAQs". Ruleworks.co.uk. Retrieved 2010-08-29.
- Jump up ^ Smith, Jamon. Tuscaloosanews.com "World’s oldest chicken starred in magic shows, was on 'Tonight Show’", Tuscaloosa News (Alabama, USA). 6 August 2006. Retrieved on 26 February 2008.
- Jump up ^ by Stonehead. "Introducing new hens to a flock « Musings from a Stonehead". Stonehead.wordpress.com. Retrieved 2010-08-29.
- ^ Jump up to: a b c Grandin, Temple; Johnson, Catherine (2005). Animals in Translation. New York, New York: Scribner. pp. 69–71. ISBN 0-7432-4769-8.
- Jump up ^ Sherwin, C.M. and Nicol, C.J., (1993). Factors influencing floor-laying by hens in modified cages. Applied Animal Behaviour Science, 36: 211-222
- Jump up ^ Joe G. Berry. "Artificial Incubation". Oklahoma Cooperative Extension Service, Oklahoma State University. Retrieved 2010-09-29.
- Jump up ^ Phillip J. Clauer. "Incubating Eggs". Virginia Cooperative Extension Service, Virginia State University. Retrieved 2010-10-01.
- Jump up ^ "Incubation Handbook". Brinsea Products Ltd. Retrieved 2010-09-30.
- Jump up ^ "How To Hatch Chicken Eggs". www.backyardchickens.com. Retrieved 2010-09-30.
- Jump up ^ Scientists Find Chickens Retain Ancient Ability to Grow Teeth Ammu Kannampilly, ABC News, 2006-02-27. Retrieved 2007-10-01.
- ^ Jump up to: a b A genetic variation map for chicken with 2.8 million single-nucleotide polymorphisms. International Chicken Polymorphism Map Consortium (GK Wong et al.) 2004. Nature 432, 717-722| doi:10.1038/nature03156 PMID 15592405
- Jump up ^ Eriksson J, Larson G, Gunnarsson U, Bed'hom B, Tixier-Boichard M, et al. (2008) Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken. PLoS Genet January 23, 2008 Genetics.plosjournals.org
- Jump up ^ Fumihito, A; Miyake, T; Sumi, S; Takada, M; Ohno, S; Kondo, N (December 20, 1994), "One subspecies of the red junglefowl (Gallus gallus gallus) suffices as the matriarchic ancestor of all domestic breeds", PNAS 91 (26): 12505–12509
- Jump up ^ Liu, Yi-Ping; Wu, Gui-Sheng; Yao, Yong-Gang; Miao, Yong-Wang; Luikart, Gordon; Baig, Mumtaz; Beja-Pereira, Albano; Ding, Zhao-Li; Palanichamy, Malliya Gounder; Zhang, Ya-Ping (2006), "Multiple maternal origins of chickens: Out of the Asian jungles", Molecular Phylogenetics and Evolution 38 (1): 12–19
- Jump up ^ Zeder, et al. (2006). "Documenting domestication: the intersection of genetics and archaeology". Trends in Genetics 22 (3): 139–155. doi:10.1016/j.tig.2006.01.007.
- Jump up ^ King, Rick (February 24, 2009), "Rat Attack", NOVA and National Geographic Television
- Jump up ^ King, Rick (February 01, 2009), "Plant vs. Predator", NOVA
- Jump up ^ West, B.; Zhou, B.X. (1988). "Did chickens go north? New evidence for domestication". J. Archaeol. Sci. 14: 515–533.
- Jump up ^ Al-Nasser, A. et al. (2007). "Overview of chicken taxonomy and domestication". World's Poultry Science Journal 63: 285–300. doi:10.1017/S004393390700147X.
- ^ Jump up to: a b c d e f CHOF : The Cambridge History of Food, 2000, Cambridge University Press, vol.1, pp496-499
- Jump up ^ DNA reveals how the chicken crossed the sea Brendan Borrell, Nature, 5 June 2007. Retrieved 2007-10-01.
- Jump up ^ A. A. Storey et al., "Radiocarbon and DNA evidence for a pre-Columbian introduction of Polynesian chickens to Chile", Proceedings of the National Academy of Sciences of the United States of America, www.pnas.org/cgi/doi/10.1073/pnas.0703993104; John Noble Wilford, "First Chickens in Americas were Brought from Polynesia, New York Times, June 5, 2007.
- Jump up ^ Indo-European and Asian origins for Chilean and Pacific chickens revealed by mtDNA. Jaime Gongora, Nicolas J. Rawlence, Victor A. Mobegi, Han Jianlin, Jose A. Alcalde, Jose T. Matus, Olivier Hanotte, Chris Moran, J. Austin, Sean Ulm, Atholl J. Anderson, Greger Larson and Alan Cooper, "Indo-European and Asian origins for Chilean and Pacific chickens revealed by mtDNA" PNAS July 29, 2008 vol. 105 no 30 Pnas.org
- Jump up ^ "Clucks and Chooks: A guide to keeping chickens".
- Jump up ^ United Poultry Concerns. "Providing a Good Home for Chickens". Retrieved 2009-05-04.
- Jump up ^ White TM, Gilden DH, Mahalingam R. "An animal model of varicella virus infection". Retrieved 2009-05-01.
- Jump up ^ "Clucks and Chooks: guide to keeping chickens".
- ^ Jump up to: a b How the Chicken Conquered the World - By Jerry Adler and Andrew Lawler - Smithsonian magazine, June 2012 [1]
- Jump up ^ The Cock by Dr. John P. Peters - Journal of the American Oriental Society, Volume 33 By American Oriental Society - American Oriental Society, 1913 - p.381 [2]
- Jump up ^ The New Testament | Matthew 26:34 | Mark 14:30 | Luke 22:34 | Matthew 26:74-75 | Mark 14:71-72 | Luke 22:60-61
- Jump up ^ The Antiquary: a magazine devoted to the study of the past, Volume 17 edited by Edward Walford, John Charles Cox, George Latimer Apperson - page 202
- Jump up ^ The Philadelphia Museum bulletin, Volumes 1-5 - By Pennsylvania Museum of Art, Pennsylvania Museum and School of Industrial Art, Philadelphia Museum of Art - p 14 - 1906
- Jump up ^ A Treasury of Jewish Quotations By Joseph L. Baron - 1985
- Jump up ^ PROVERBS 10-31, Volume 18 - Michael V. Fox - Yale University Press 2009 - 704 pages
- Jump up ^ [3] The Cambridge History of the Pacific Islanders By Donald Denoon, Malama Meleisea - Cambridge University Press, Mar 25, 2004 - page 56
- Jump up ^ [4] Anthropological Genetics: Theory, Methods and Applications edited by Michael H. Crawford - Cambridge University Press, Nov 30, 2006 - page 411
- Jump up ^ [5] Regional Greek Cooking By Dean Karayanis, Catherine Karayanis - Hippocrene Books, Mar 1, 2008 - page 176
- Jump up ^ [6] Cooking With the Bible: Biblical Food, Feasts, And Lore By Anthony F. Chiffolo, Rayner W. Hesse - Greenwood Publishing Group, Aug 30, 2006 - page 207
- Jump up ^ [7] A classical and archaeological dictionary of the manners, customs, laws, institutions, arts, etc. of the celebrated nations of antiquity, and of the middle ages: To which is prefixed A synoptical and chronological view of ancient history - P. Austin Nuttall - Printed for Whittaker and co., 1840 - page 601
- Jump up ^ [8] Chambers's information for the people, ed. by W. and R. Chambers - Chambers W. and R., ltd - page 458
- Jump up ^ [9] A Cabinet of Roman Curiosities: Strange Tales and Surprising Facts from the World's Greatest Empire by J. C. McKeown - Oxford University Press, Jul 22, 2010 - page 131
- Jump up ^ [10] A History of Food By Maguelonne Toussaint-Samat - John Wiley & Sons, Mar 25, 2009 - page 305
- Jump up ^ [A History of Food By Maguelonne Toussaint-Samat - John Wiley & Sons, Mar 25, 2009 - page 305]
- Jump up ^ Maguelonne Toussaint-Samat, (Anthea Bell, translator) The History of Food, Ch. 11 "The History of Poultry", revised ed. 2009, p. 305.
- Jump up ^ [11] The New England farmer, Volume 6 By Thomas Greene Fessenden - Thomas W. Shepard, 1828 - page 69
- Jump up ^ [12] The Wisdom of Birds: An Illustrated History of Ornithology By Tim Birkhead - Bloomsbury Publishing, Mar 7, 2011 - page 278
- Jump up ^ [13] The Enigmas of Easter Island By Paul Bahn, John Flenley - Oxford University Press, May 29, 2003 - page 96
- Jump up ^ "Broiler Chickens Fact Sheet // Animals Australia". Animalsaustralia.org. Retrieved 2010-08-29.
- Jump up ^ Guinness World Records 2011 ed. by Craig Glenday - page 286
- ^ Jump up to: a b Browne, Anthony (2002-03-10). "Ten weeks to live". The Guardian (London). Retrieved 2010-04-28.
- Jump up ^ Patwardhan, D. and King, A., (2011). Review: feed withdrawal and non feed withdrawal moult. World's Poultry Science Journal, 67: 253-268
- Jump up ^ Webster, A.B., (2003). Physiology and behavior of the hen during induced moult. Poultry Science, 82: 992-1002
- Jump up ^ Molino, A.B., Garcia, E.A., Berto, D.A., Pelícia, K., Silva, A.P. and Vercese F., (2009). The Effects of Alternative Forced-Molting Methods on The Performance and Egg Quality of Commercial Layers. Brazilian Journal of Poultry Science, 11: 109-113
- Jump up ^ Yousaf, M. and Chaudhry, A.S., (2008). History, changing scenarios and future strategies to induce moulting in laying hens. World's Poultry Science Journal, 64: 65-75
- Jump up ^ [14] Poultry Genetics, Breeding and Biotechnology edited by W. M. Muir, S. E. Aggrey - CABI, Sep 4, 2003 - page 5
- Jump up ^ [15] International Egg Commission IEC London Egg Conference - Sept. 9 to Sep. 13, 2012
- Jump up ^ [16] WATT Ag Net - Watt Publishing Co
Further reading
- Green-Armytage, Stephen (October 2000). Extraordinary Chickens. Harry N. Abrams. ISBN 0-8109-3343-8.
- Smith, Page; Charles Daniel (April 2000). The Chicken Book. University of Georgia Press. ISBN 0-8203-2213-X.
External links
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Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.Ostrich
From Wikipedia, the free encyclopediaFor other uses, see Ostrich (disambiguation).The Ostrich or Common Ostrich (Struthio camelus) is either one or two species of large flightless birds native to Africa, the only living member(s) of the genus Struthio, which is in the ratite family. Some analyses indicate that the Somali Ostrich may be better considered a full species separate from the Common Ostrich, but most taxonomists consider it to be a subspecies.Ostrich
Temporal range: Pleistocene–present Pleistocene to Recentmale (left) and female ostriches Conservation status Scientific classification Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Class: Aves Superorder: Paleognathae Order: Struthioniformes Family: Struthionidae Genus: Struthio Species: S. camelus Binomial name Struthio camelus
Linnaeus, 1758[2]Subspecies S. c. australis Gurney, 1868[2]
Southern Ostrich
S. c. camelus Linnaeus, 1758[2]
North African Ostrich
S. c. massaicus Neumann, 1898[2]
Masai Ostrich
†S. c. syriacus Rothschild, 1919[2]
Arabian Ostrich
S. c. molybdophanes Reichenow, 1883[2]
Somali OstrichStruthio camelus distribution map S. c. camelus S. c. molybdophanes S. c. massaicus S. c. australis
The ostrich shares the order Struthioniformes with the kiwis, emus, rheas, and cassowaries. It is distinctive in its appearance, with a long neck and legs, and can run at up to about 70 km/h (43 mph),[3] the fastest land speed of any bird.[4] The ostrich is the largest living species of bird and lays the largest eggs of any living bird (extinct elephant birds of Madagascar and the giant moa of New Zealand laid larger eggs).
The ostrich's diet consists mainly of plant matter, though it also eats invertebrates. It lives in nomadic groups of 5 to 50 birds. When threatened, the ostrich will either hide itself by lying flat against the ground, or run away. If cornered, it can attack with a kick of its powerful legs. Mating patterns differ by geographical region, but territorial males fight for a harem of two to seven females.
The ostrich is farmed around the world, particularly for its feathers, which are decorative and are also used as feather dusters. Its skin is used for leather products and its meat is marketed commercially.[3]
Contents
[hide]Description[edit]
Ostriches usually weigh from 63 to 145 kilograms (139–320 lb),[3][5] Ostriches of the East African race (S. c. massaicus) averaged 115 kg (254 lb) in males and 100 kg (220 lb) in females, while the nominate subspecies[clarification needed] was found to average 111 kg (245 lb) in unsexed adults.[3] Exceptional male ostriches (in the nominate subspecies) can weigh up to 156.8 kg (346 lb).[3] At sexual maturity (two to four years), male ostriches can be from 2.1 to 2.8 m (6 ft 11 in to 9 ft 2 in) in height, while female ostriches range from 1.7 to 2 m (5 ft 7 in to 6 ft 7 in) tall.[3] New chicks are fawn in colour, with dark brown spots.[6] During the first year of life, chicks grow at about 25 cm (9.8 in) per month. At one year of age, ostriches weigh approximately 45 kilograms (99 lb). Their lifespan is up to 40–45 years.
The feathers of adult males are mostly black, with white primaries and a white tail. However, the tail of one subspecies is buff. Females and young males are greyish-brown and white. The head and neck of both male and female ostriches is nearly bare, with a thin layer of down.[5][6] The skin of the female's neck and thighs is pinkish gray,[6] while the male's is blue-gray, gray or pink dependent on subspecies.
- Head
- Beak open
- Ostrich skull
- Foot
- Claws on the wings
Their skin varies in colour depending on the subspecies, with some having light or dark gray skin and others having pinkish or even reddish skin.[3] The strong legs of the ostrich are unfeathered and show bare skin, with the tarsus (the lowest upright part of the leg) being covered in scales: red in the male, black in the female.[3] The tarsus of the ostrich is the largest of any living bird, measuring 39 to 53 cm (15 to 21 in) in length.[3] The bird has just two toes on each foot (most birds have four), with the nail on the larger, inner toe resembling a hoof. The outer toe has no nail.[citation needed] The reduced number of toes is an adaptation that appears to aid in running, useful for getting away from predators. Ostriches can run at a speed over 70 km/h (43 mph) and can cover 3 to 5 m (9.8 to 16 ft) in a single stride.[10] The wings reach a span of about 2 metres (6 ft 7 in), and the wing chord measurement of 90 cm (35 in) is around the same size as for the largest flying birds.[3][11] The wings are used in mating displays and to shade chicks. The feathers lack the tiny hooks that lock together the smooth external feathers of flying birds, and so are soft and fluffy and serve as insulation. Ostriches can tolerate a wide range of temperatures. In much of their habitat, temperatures vary as much as 40 °C (100 °F) between night and day. Their temperature control mechanism relies on action by the bird, which uses its wings to cover the naked skin of the upper legs and flanks to conserve heat, or leaves these areas bare to release heat. They have 50–60 tail feathers, and their wings have 16 primary, four alular and 20–23 secondary feathers.[3]
The ostrich's sternum is flat, lacking the keel to which wing muscles attach in flying birds.[12] The beak is flat and broad, with a rounded tip.[5] Like all ratites, the ostrich has no crop,[13] and it also lacks a gallbladder.[14] They have three stomachs, and the caecum is 71 cm (28 in) long. Unlike all other living birds, the ostrich secretes urine separately from faeces.[15] All other birds store the urine and faeces combined in the coprodeum, but the ostrich stores the faeces in the terminal rectum.[15] They also have unique pubic bones that are fused to hold their gut. Unlike most birds, the males have a copulatory organ, which is retractable and 8 in (20 cm) long. Their palate differs from other ratites in that the sphenoid and palatal bones are unconnected.[3]
Taxonomy[edit]
The ostrich was originally described by Linnaeus in his 18th-century work, Systema Naturae under its current binomial name.[16] Its scientific name is derived from Latin, struthio meaning "ostrich" and camelus meaning "camel", alluding to its dry habitat.[17]
The ostrich belongs to the ratite order Struthioniformes. Other members include rheas, emus, cassowaries, moa, kiwi and the largest bird ever, the now-extinct Elephant Bird (Aepyornis). However, the classification of the ratites as a single order has always been questioned, with the alternative classification restricting the Struthioniformes to the ostrich lineage and elevating the other groups.
Subspecies[edit]
Five subspecies are recognized:
- Common Ostrich (S. struthio) complex:
- S. c. australis, Southern Ostrich, southern Africa. It is found south of the Zambezi and Cunene rivers. It is farmed for its meat, leather and feathers in the Little Karoo area of Cape Province.[18]
- S. c. camelus, North African Ostrich, or Red-necked Ostrich, North Africa. Historically it was the most widespread subspecies, ranging from Ethiopia and Sudan in the east throughout the Sahel[19] to Senegal and Mauritania in the west, and north to Egypt and southern Morocco, respectively. It has now disappeared from large parts of this range,[20] and it only remains in 6 of the 18 countries where it originally occurred, leading some to consider it Critically Endangered.[21] It is the largest subspecies, at 2.74 m (9.0 ft) in height and up to 154 kilograms (340 lb) in weight.[22] The neck is pinkish-red, the plumage of males is black and white, and the plumage of females is grey.[22]
- S. c. massaicus, Masai Ostrich, East Africa. It has some small feathers on its head, and its neck and thighs are pink. During the mating season, the male's neck and thighs become brighter. Its range is essentially limited to southern Kenya and eastern Tanzania[19] and Ethiopia and parts of Southern Somalia.[22]
- S. c. syriacus, Arabian Ostrich or Middle Eastern Ostrich, Middle East. Was formerly very common in the Arabian Peninsula, Syria,[19] and Iraq; it became extinct around 1966.
- S. c. molybdophanes, Somali Ostrich, southern Ethiopia, northeastern Kenya, and Somalia.[19] The neck and thighs are grey-blue, and during the mating season, the male's neck and thighs become brighter and bluer. The females are more brown than those of other subspecies.[22] It generally lives in pairs or alone, rather than in flocks. Its range overlaps with S. c. massaicus in northeastern Kenya.[22]
The population from Río de Oro was once separated as Struthio camelus spatzi because its eggshell pores were shaped like a teardrop and not round. However, as there is considerable variation of this character and there were no other differences between these birds and adjacent populations of S. c. camelus, the separation is no longer considered valid.[24] This population disappeared in the latter half of the 20th century. There were 19th century reports of the existence of small ostriches in North Africa; these are referred to as Levaillant's Ostrich (Struthio bidactylus) but remain a hypothetical form not supported by material evidence.[25]
Evolution[edit]
The earliest fossil of ostrich-like birds is the Palaeotis living near the Asiatic steppes,[3] from the Middle Eocene, a middle-sized flightless bird that was originally believed to be a bustard. Apart from this enigmatic bird, the fossil record of the ostriches continues with several species of the modern genus Struthio which are known from the Early Miocene onwards. While the relationship of the African species is comparatively straightforward, a large number of Asian species of ostrich have been described from fragmentary remains, and their interrelationships and how they relate to the African Ostriches are confusing. In China, ostriches are known to have become extinct only around or even after the end of the last ice age; images of ostriches have been found there on prehistoric pottery and petroglyphs.
Several of these fossil forms are ichnotaxa (that is, classified according to the organism's footprints or other trace rather than its body) and their association with those described from distinctive bones is contentious and in need of revision pending more good material.[26]
- Struthio coppensi (Early Miocene of Elizabethfeld, Namibia)
- Struthio linxiaensis (Liushu Late Miocene of Yangwapuzijifang, China)
- Struthio orlovi (Late Miocene of Moldavia)
- Struthio karingarabensis (Late Miocene – Early Pliocene of SW and CE Africa) – oospecies(?)
- Struthio kakesiensis (Laetolil Early Pliocene of Laetoli, Tanzania) – oospecies
- Struthio wimani (Early Pliocene of China and Mongolia)
- Struthio daberasensis (Early – Middle Pliocene of Namibia) – oospecies
- Struthio brachydactylus (Pliocene of Ukraine)
- Struthio chersonensis (Pliocene of SE Europe to WC Asia) – oospecies
- Asian Ostrich, Struthio asiaticus (Early Pliocene – Late Pleistocene of Central Asia to China ?and Morocco)
- Giant Ostrich, Struthio dmanisensis (Late Pliocene/Early Pleistocene of Dmanisi, Georgia)
- Struthio oldawayi (Early Pleistocene of Tanzania) – probably subspecies of S. camelus
- Struthio anderssoni – oospecies (?)
Distribution and habitat[edit]
Ostriches formerly occupied Africa north and south of the Sahara, East Africa, Africa south of the rain forest belt, and much of Asia Minor.[3] Today ostriches prefer open land and are native to the savannas and Sahel of Africa, both north and south of the equatorial forest zone.[11] In Southwest Africa they inhabit the semi-desert or true desert. They rarely go above 100 m (330 ft).[3] Farmed ostriches in Australia have established feral populations.[1] The Arabian Ostriches in the Near and Middle East were hunted to extinction by the middle of the 20th century. Ostriches have occasionally been seen inhabiting islands on the Dahlak Archipelago, in the Red Sea near Eritrea.
Behaviour and ecology[edit]
Ostriches normally spend the winter months in pairs or alone. Only 16 percent of ostrich sightings were of more than two birds.[3] During breeding season and sometimes during extreme rainless periods ostriches live in nomadic groups of five to 100 birds (led by a top hen) that often travel together with other grazing animals, such as zebras or antelopes.[11] Ostriches are diurnal, but may be active on moonlit nights. They are most active early and late in the day.[3] The male ostrich territory is between 2 and 20 km2 (0.77 and 7.7 sq mi).[6]Pair "dancing".
With their acute eyesight and hearing, ostriches can sense predators such as lions from far away. When being pursued by a predator, they have been known to reach speeds in excess of 70 km/h (43 mph),[3] and can maintain a steady speed of 50 km/h (31 mph), which makes the ostrich the world's fastest two-legged animal.[27] When lying down and hiding from predators, the birds lay their heads and necks flat on the ground, making them appear like a mound of earth from a distance, aided by the heat haze in their hot, dry habitat.[28][29]
When threatened, ostriches run away, but they can cause serious injury and death with kicks from their powerful legs.[11] Their legs can only kick forward.[30] Contrary to popular belief, ostriches do not bury their heads in sand to avoid danger.[31] This myth likely began with Pliny the Elder (AD 23–79), who wrote that ostriches "imagine, when they have thrust their head and neck into a bush, that the whole of their body is concealed."[32] This may have been a misunderstanding of their sticking their heads in the sand to swallow sand and pebbles,[33] or, as National Geographic suggests, of the defensive behavior of lying low, so that they may appear from a distance to have their head buried.[34]
Feeding[edit]
They mainly feed on seeds, shrubs, grass, fruit and flowers;[3][6] occasionally they also eat insects such as locusts. Lacking teeth, they swallow pebbles that act as gastroliths to grind food in the gizzard. When eating, they will fill their gullet with food, which is in turn passed down their esophagus in the form of a ball called a bolus. The bolus may be as much as 210 ml (7.1 US fl oz). After passing through the neck (there is no crop) the food enters the gizzard and is worked on by the aforementioned pebbles. The gizzard can hold as much as 1,300 g (46 oz), of which up to 45% may be sand and pebbles.[6] Ostriches can go without drinking for several days, using metabolic water and moisture in ingested plants,[35] but they enjoy liquid water and frequently take baths where it is available.[11] They can survive losing up to 25% of their body weight through dehydration.[36]
Mating[edit]
Ostriches become sexually mature when they are 2 to 4 years old; females mature about six months earlier than males. As with other birds, an individual may reproduce several times over its lifetime. The mating season begins in March or April and ends sometime before September. The mating process differs in different geographical regions. Territorial males typically boom in defence of their territory and harem of two to seven hens;[37] the successful male may then mate with several females in the area, but will only form a pair bond with a 'major' female.[37]
The cock performs with his wings, alternating wing beats, until he attracts a mate. They will go to the mating area and he will maintain privacy by driving away all intruders. They graze until their behaviour is synchronized, then the feeding becomes secondary and the process takes on a ritualistic appearance. The cock will then excitedly flap alternate wings again, and start poking on the ground with his bill. He will then violently flap his wings to symbolically clear out a nest in the soil. Then, while the hen runs a circle around him with lowered wings, he will wind his head in a spiral motion. She will drop to the ground and he will mount for copulation.[3] Ostriches raised entirely by humans may not direct their courtship behaviour at other ostriches, but toward their human keepers.[38]
- Only 15% of the surviving chicks reach 1 year of age
- Ostrich chick
- Ostrich hen with chicks
- A female incubating eggs in a shallow nest on the ground in the Serengeti, Tanzania
- Ostrich nest
Predators[edit]
As a flightless species in the rich biozone of the African savanna, the ostrich must face a variety of formidable predators throughout its life cycle. Animals that prey on ostriches of all ages may include cheetahs, lions, leopards, African hunting dogs, and spotted hyena.[3] Ostriches can often outrun most of their predators in a pursuit, so most predators will try to ambush an unsuspecting bird using obstructing vegetation or other objects.[43] A notable exception is the cheetah, which is the most prolific predator of adult ostriches due to its own great running speeds.[44]
Common predators of nests and young ostriches include jackals, various birds of prey, warthogs, mongoose and Egyptian vultures.[37][45] If the nest or young are threatened, either or both of the parents may create a distraction, feigning injury.[6] However, they may sometimes fiercely fight predators, especially when chicks are being defended, and have been capable of killing even their largest enemies, the lions, in such confrontations.[34]
Physiology[edit]
Respiration[edit]
Anatomy[edit]
Morphology of the ostrich lung indicates that the structure conforms to that of the other avian species, but still retains parts of its primitive avian species, ratite, structure.[46] The opening to the respiratory pathway begins with the laryngeal cavity lying posterior to the choanae within the buccal cavity.[47] The tip of the tongue then lies anterior to the choanae, excluding the nasal respiratory pathway from the buccal cavity.[47] The trachea lies ventrally to the cervical vertebrae extending from the larynx to the syrinx, where the trachea enters the thorax, dividing into two primary bronchi, one to each lung, in which they continue directly through to become mesobronchi.[47] Ten different air sacs attach to the lungs to form areas for respiration.[47] The most posterior air sacs (abdominal and post-thoracic) differ in that the right abdominal air sac is relatively small, lying to the right of the mesentery, and dorsally to the liver.[47] While the left abdominal air sac is large and lies to the left of the mesentery.[47] The connection from the main mesobronchi to the more anterior air sacs including the interclavicular, lateral clavicular, and pre-thoracic sacs known as the ventrobronchi region. While the caudal end of the mesobronchus branches into several dorsobronchi. Together, the ventrobronchi and dorsobronchi are connected by intra-pulmonary airways, the parabronchi, which form an arcade structure within the lung called the paleopulmo. It is the only structure found in primitive birds such as ratites.[47] The largest air sacs found within the respiratory system are those of the post-thoracic region, while the others decrease in size respectively, the interclavicular (unpaired), abdominal, pre-thoracic, and lateral clavicular sacs.[48] The adult ostrich lung lacks connective tissue known as interparabronchial septa, which render strength to the non-compliant avian lung in other bird species. Due to this the lack of connective tissue surrounding the parabronchi and adjacent parabronchial lumen, they exchange blood capillaries or avascular epithelial plates.[46] Like mammals, ostrich lungs contain an abundance of type II cells at gas exchange sites; an adaptation for preventing lung collapse during slight volume changes. [46]Diagrammatic location of the air sacs of the Ostrich
Function[edit]
The ostrich is a thermoregulator and maintains a body temperature of 38.1–39.7 °C in its extreme living temperature conditions, such as the heat of the savanna and desert regions of Africa.[49] The ostrich utilizes its respiratory system via a costal pump for ventilation rather than a diaphragmatic pump as seen in most mammals.[47] Thus, they are able to use a series of air sacs connected to the lungs. The use of air sacs forms the basis for the three main avian respiratory characteristics:
- Air is able to flow continuously in one direction through the lung, making it more efficient than the mammalian lung.
- It provides birds with a large residual volume, allowing them to breathe much more slowly and deeply than a mammal of the same body mass.
- It provides a large source of air that is used not only for gaseous exchange, but also for the transfer of heat by evaporation.[47]
To compensate for the large “dead” space, the ostrich trachea lacks valves to allow faster inspiratory air flow.[51] In addtion, the total lung capacity of the respiratory system, (including the lungs and ten air sacs) of a 100 kg ostrich is about 15 L, with a tidal volume ranging from 1.2 to 1.5 L.[48][51] The tidal volume is seen to double resulting in a 16-fold increase in ventilation.[47] Overall, ostrich respiration can be thought of as a high velocity-low pressure system.[48] At rest, there is small pressure differences between the ostrich air sacs and the atmosphere, suggesting simultaneous filling and emptying of the air sacs.[51]
The increase in respiration rate from the low range to the high range is sudden and occurs in response to hyperthermia. Birds lack sweat glands, so when placed under stress due to heat, they heavily rely upon increased evaporation from the respiratory system for heat transfer. This rise in respiration rate however is not necessarily associated with a greater rate of oxygen consumption.[47] Therefore, unlike other birds, the ostrich is able to dissipate heat through panting without experiencing respiratory alkalosis by modifying ventilation of the respiratory medium. During hyperpnea ostriches pant at a respiratory rate of 40–60 cycles/minute, versus their resting rate of 6–12 cycles/minute.[48] Hot, dry and moisture lacking properties of the ostrich respiratory medium affects oxygen's diffusion rate (Henry's Law).[50]
Ostrich develop via Intussusceptive angiogenesis, a mechanism of blood vessel formation, characterizing many organs.[46] It is not only involved in vasculature expansion, but also in angioadaptation of vessels to meet physiological requirements.[46] The use of such mechanisms demonstrates an increase in the later stages of lung development, along with elaborate parabronchial vasculature, and reorientation of the gas exchange blood capillaries to establish the crosscurrent system at the blood-gas barrier.[46] The blood–gas barrier (BGB) of their lung tissue is thick. The advantage of this thick barrier may be protection from damage by large volumes of blood flow in times of activity, such as running,[52] since air is pumped by the air sacs rather than the lung itself. As a result the capillaries in the parabronchi have thinner walls, permitting more efficient gaseous exchange.[47] In combination with separate pulmonary and systemic circulatory systems, it helps to reduce stress on the BGB.[46]
Circulation[edit]
Heart Anatomy[edit]
The ostrich heart is a closed system, contractile chamber. It is composed of myogenic muscular tissue associated with heart contraction features. There is a double circulatory plan in place possessing both a pulmonary circuit and systemic circuit.[50]
The ostrich’s heart has similar features to other avian species like having a conically shaped heart, and being enclosed by a pericardium layer.[53] Moreover, similarities also include a larger right atrium volume, and a thicker left ventricle to fulfil the systemic circuit.[53] The ostrich heart has three features that are absent in related birds:
- The right atrioventricular valve is fixed to the interventricular septum, by a thick muscular stock, which prevents back-flow of blood into the atrium when ventricular systole is occurring.[53] In the fowl this valve is only connected by a short septal attachment.[53]
- Pulmonary veins attach to the left atrium separately, and also the opening to the pulmonary veins are separated by a septum.[53]
- moderator bands, full of purkinje fibers, are found in different locations in the left and right ventricles.[53] These bands are associated with contractions of the heart and suggests this difference causes the left ventricle to contract harder to create more pressure for a completed circulation of blood around the body.[53]
The coronary arteries start in the right and left aortic sinus and provide blood to the heart muscle in a similar fashion to most other vertebrates.[55] Other domestic birds capable of flight have three or more coronary arteries that supply blood to the heart muscle. The blood supply by the coronary arteries are fashioned starting as a large branch over the surface of the heart. It then moves along the coronary groove and continues on into the tissue as interventricular branches toward the apex of the heart. The atria, ventricles, and septum are supplied of blood by this modality. The deep branches of the coronary arteries found with in the heart tissue are small and supply the interventricular and right atrioventricular valve with blood nutrients for which to carry out their processes. The interatrial artery of the ostrich is small in size and exclusively supplies blood to only part of the left auricle and interatrial septum.[24]
These purkinje fibers (p-fibers) found in the hearts moderator bands are a specialized cardiac muscle fiber that causes the heart to contract.[56] The purkinje cells are mostly found within both the endocardium and the sub-endocardium.[56] The sinoatrial node shows a small concentration of purkinje fibers, however, continuing through the conducting pathway of the heart the bundle of his shows the highest amount of these purkinje fibers.[56]
Blood composition[edit]
The hematocrit count of the ostrich constitutes 40% of the average man, however, the red blood cells of the ostrich size about three times larger.[57] The blood oxygen affinity, known as P50, is higher than that of both humans and similar avian species.[57] The reason for this decreased oxygen affinity is due to the hemoglobin configuration found in the ostrich blood.[57] The ostrich’s tetramer is composed of hemoglobin type A and D, compared to typical mammalian tetramers composed of hemoglobin type A and B; hemoglobin D configuration causes a decreased oxygen affinity at the site of the respiratory surface.[57]
During the embryonic stage Hemoglobin E is present.[58] This subtype increases oxygen affinity in order to transport oxygen across the allantoic membrane of the embryo.[58] This can be attributed to the high metabolic need of the developing embryo, thus high oxygen affinity serves to satisfy this demand. When the chick hatches hemoglobin E diminishes while hemoglobin A and D increase in concentration.[58] This shift in hemoglobin concentration results in both decreased oxygen affinity and increased P50 value.[58]
Furthermore, the P50 value is influenced by differing organic modulators.[58] In the typical mammalian RBC 2,3 – DPG causes a lower affinity for oxygen. 2,3- DPG constitutes approximately 42–47%, of the cells phosphate of the embryonic ostrich.[58] However, the adult ostrich have no traceable 2,3- DPG.In place of 2,3-DPG the ostrich uses inositol polyphosphates (IPP), which vary from 1–6 phosphates per molecule.[58] In relation to the IPP, the ostrich also uses ATP to lower oxygen affinity.[58] ATP has a consistent concentration of phosphate in the cell.[58] Around 31% at incubation periods, and dropping to 16–20% in 36 day old chicks.[58] However, IPP has low concentrations, around 4%, of total phosphate concentration in embryonic stages; However, the IPP concentration jumps to 60% of total phosphate of the cell.[58] The majority of phosphate concentration switches from 2,3- DPG to IPP, suggesting the result of the overall low oxygen affinity is due to these varying polyphosphates.[58]
Concerning immunological adaptation, it was discovered that wild ostrich's have a pronounced non specific immunity defense, with blood content reflecting high values of lysosome, and phagocyte cells in medium. This is in contrast to domesticated ostriches, who in captivity develop high concentration of immunoglobulin antibodies in their circulation, indicating an acquired immunological response. It is suggested that this immunological adaptability may allow this species to have a high success rate of survival in variable environmental settings.[59]
Status and conservation[edit]
The wild ostrich population has declined drastically in the last 200 years, with most surviving birds in reserves or on farms.[3] However, its range remains very large (9,800,000 square kilometres (3,800,000 sq mi)), leading the IUCN and BirdLife International to treat it as a species of Least Concern.[1] Of its 5 subspecies, the Middle Eastern Ostrich (S. c. syriacus) became extinct around 1966, and the North African Ostrich (S. c. camelus) has declined to the point where it now is included on CITES Appendix I and some treat it as Critically Endangered.[20][21][22]
Ostriches and humans[edit]
Ostriches have inspired cultures and civilizations for 5,000 years in Mesopotamia and Egypt. A statue of Arsinoe II of Egypt riding an ostrich was found in a tomb in Egypt.[60] The Kalahari bushmen still use their eggs as water jugs.[3][61]Scene with ostriches, Roman mosaic, 2nd century AD
Hunter-gatherers in the Kalahari use ostrich eggshells as water containers in which they puncture a hole to enable them to be used as canteens. The presence of such eggshells with engraved hatched symbols dating from the Howiesons Poort period of the Middle Stone Age at Diepkloof Rock Shelter in South Africa suggests ostriches were an important part of human life as early as 60,000 BP.[62]
Hunting and farming[edit]
In Roman times, there was a demand for ostriches to use in venatio games or cooking. They have been hunted and farmed for their feathers, which at various times have been popular for ornamentation in fashionable clothing (such as hats during the 19th century). Their skins are valued for their leather. In the 18th century they were almost hunted to extinction; farming for feathers began in the 19th century. At the start of the 20th century there were over 700,000 birds in captivity.[6] The market for feathers collapsed after World War I, but commercial farming for feathers and later for skins and meat became widespread during the 1970s. Ostriches are so adaptable that they can be farmed in climates ranging from South Africa to Alaska.
Ostriches were farmed for their feathers in South Africa beginning in the 19th century. According to Frank G. Carpenter, the English are credited with first taming ostriches outside Cape Town. Farmers captured baby ostriches and raised them successfully on their property, and were able to obtain a crop of feathers every seven to eight months instead of killing wild ostriches for their feathers.[63]
It is claimed that ostriches produce the strongest commercial leather.[64] Ostrich meat tastes similar to lean beef and is low in fat and cholesterol, as well as high in calcium, protein and iron. Uncooked, it is dark red or cherry red, a little darker than beef.[65]
Attacks[edit]
Ostriches typically avoid humans in the wild, since they correctly assess humans as potential predators, and, if approached, often run away. However, ostriches may turn aggressive rather than run when threatened, especially when cornered, and may also attack when they feel the need to defend their offspring or territories. Similar behaviors are noted in captive or domesticated ostriches, which retain the same natural instincts and can occasionally respond aggressively to stress. When attacking a person, ostriches kick with their powerful feet, armed with long claws, which are capable of disemboweling or killing a person with a single blow.[66] In one study of ostrich attacks, it was estimated that two to three attacks that result in serious injury or death occur each year in the area of Oudtshoorn, South Africa, where a large number of ostrich farms abut against both feral and wild ostrich populations.[42]
A Jacksonville, Florida, man with an ostrich-drawn cart, circa 1911Racing[edit]
See also: List of racing forms#Animal racingIn some countries, people race each other on the backs of ostriches. The practice is common in Africa[67] and is relatively unusual elsewhere.[68] The ostriches are ridden in the same way as horses with special saddles, reins, and bits. However, they are harder to manage than horses.[69]
The racing is also a part of modern South African culture.[70] Within the United States, a tourist attraction in Jacksonville, Florida called 'The Ostrich Farm' opened up in 1892; it and its races became one of the most famous early attractions in the history of Florida.[71]
In the United States, Chandler, Arizona hosts the annual 'Ostrich Festival' which features ostrich races.[72][73] Racing has also occurred at many other locations such as Virginia City in Nevada, Canterbury Park in Minnesota,[74] Prairie Meadows in Iowa, and Ellis Park in Kentucky.[75]
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Further reading[edit]
- Cooper, J. C. (1992). Symbolic and Mythological Animals. New York, NY: Harpercollins. pp. 170–171. ISBN 1-85538-118-4.
- Folch, A. (1992). "Family Struthionidae (Ostrich)". In del Hoya, Josep; Sargatal, Jordi. Handbook of the Birds of the World. 1, Ostrich to Ducks. Barcelona: Lynx Edicions. pp. 76–83. ISBN 84-87334-09-1.
- O'Shea, Michael Vincent; Foster, Ellsworth D.; Locke, George Herbert, eds. (1918). "Ostrich". 6. Chicago, IL: The World Book, Inc. pp. 4422–4424. Retrieved 18 July 2009.
External links[edit]
Look up Ostrich in Wiktionary, the free dictionary. Wikimedia Commons has media related to Struthio camelus. Works related to a description of traditional methods used by Arabs to capture wild ostriches. at Wikisource
- (Common) Ostrich – Species text in The Atlas of Southern African Birds.
- British Domesticated Ostrich Association
- Index for various ostrich studies and papers
- World Ostrich Association.
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Categories:- IUCN Red List least concern species
- Domesticated birds
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- Bird genera
- Livestock
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- Struthio
- Birds of Africa
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