98-422: Feathers are epidermal growths that form a distinctive outer covering, or plumage , on both avian (bird) and some non-avian dinosaurs and other archosaurs . They are the most complex integumentary structures found in vertebrates and an example of a complex evolutionary novelty. They are among the characteristics that distinguish the extant birds from other living groups. Although feathers cover most of
196-495: A crest of feathers on their heads. Although feathers are light, a bird's plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators for birds in their habitats, and serve as camouflage for predators looking for a meal. As with fish, the top and bottom colors may be different, in order to provide camouflage during flight. Striking differences in feather patterns and colors are part of
294-455: A clade consisting of moas and tinamous, followed by the final two branches: a clade of emus plus cassowaries and one of elephant birds plus kiwis. Vicariant speciation based on the plate tectonic split-up of Gondwana followed by continental drift would predict that the deepest phylogenetic split would be between African and all other ratites, followed by a split between South American and Australo-Pacific ratites, roughly as observed. However,
392-408: A combination of both. Most feather pigments are melanins (brown and beige pheomelanins , black and grey eumelanins ) and carotenoids (red, yellow, orange); other pigments occur only in certain taxa – the yellow to red psittacofulvins (found in some parrots ) and the red turacin and green turacoverdin ( porphyrin pigments found only in turacos ). Structural coloration is involved in
490-562: A light build, et cetera. The basal metabolic rate of flighted species is much higher than that of flightless terrestrial birds. But energetic efficiency can only help explain the loss of flight when the benefits of flying are not critical to survival. Research on flightless rails indicates the flightless condition evolved in the absence of predators. This shows flight to be generally necessary for survival and dispersal in birds. In apparent contradiction to this, many landmasses occupied by ratites are also inhabited by predatory mammals. However,
588-494: A modernly feathered theropod ancestor, providing insight into the dinosaur-bird transition. The specimen shows distribution of large pennaceous feathers on the forelimbs and tail, implying that pennaceous feathers spread to the rest of the body at an earlier stage in theropod evolution. The development of pennaceous feathers did not replace earlier filamentous feathers. Filamentous feathers are preserved alongside modern-looking flight feathers – including some with modifications found in
686-539: A number of industrial applications as a medium for culturing microbes, biodegradable polymers, and production of enzymes. Feather proteins have been tried as an adhesive for wood board. Some groups of Native people in Alaska have used ptarmigan feathers as temper (non-plastic additives) in pottery manufacture since the first millennium BC in order to promote thermal shock resistance and strength. Eagle feathers have great cultural and spiritual value to Native Americans in
784-708: A popular trend as a hairstyle accessory, with feathers formerly used as fishing lures now being used to provide color and style to hair. Feather products manufacturing in Europe has declined in the last 60 years, mainly due to competition from Asia. Feathers have adorned hats at many prestigious events such as weddings and Ladies Day at racecourses (Royal Ascot). The functional view on the evolution of feathers has traditionally focused on insulation, flight and display. Discoveries of non-flying Late Cretaceous feathered dinosaurs in China, however, suggest that flight could not have been
882-486: A quick escape decreases. Moreover, raptor species tend to become generalist predators on islands with low species richness, as opposed to specializing in the predation of birds. An increase in leg size compensates for a reduction in wing length in insular birds that have not lost flight by providing a longer lever to increase force generated during the thrust that initiates takeoff. Ratites in general have many physical characteristics in common, although many are not shared by
980-435: A role in the evolution of powered flight. The coloration of feathers is believed to have evolved primarily in response to sexual selection . In fossil specimens of the paravian Anchiornis huxleyi and the pterosaur Tupandactylus imperator , the features are so well preserved that the melanosome (pigment cells) structure can be observed. By comparing the shape of the fossil melanosomes to melanosomes from extant birds,
1078-459: A small opening on the side (distal umbilicus). Hatchling birds of some species have a special kind of natal down feathers (neossoptiles) which are pushed out when the normal feathers (teleoptiles) emerge. Flight feathers are stiffened so as to work against the air in the downstroke but yield in other directions. It has been observed that the orientation pattern of β-keratin fibers in the feathers of flying birds differs from that in flightless birds:
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#17327762765951176-435: A supply of powder down feathers that grow continuously, with small particles regularly breaking off from the ends of the barbules. These particles produce a powder that sifts through the feathers on the bird's body and acts as a waterproofing agent and a feather conditioner . Powder down has evolved independently in several taxa and can be found in down as well as in pennaceous feathers. They may be scattered in plumage as in
1274-596: A ten-million-year-long window of opportunity for evolution of avian gigantism on continents may have existed following the extinction of the non-avian dinosaurs , in which ratites were able to fill vacant herbivorous niches before mammals attained large size. Some authorities, though, have been skeptical of the new findings and conclusions. Kiwi and tinamous are the only palaeognath lineages not to evolve gigantism, perhaps because of competitive exclusion by giant ratites already present on New Zealand and South America when they arrived or arose. The fact that New Zealand has been
1372-644: A trait that evolved independently multiple times in different ratite lineages. Most parts of the former supercontinent Gondwana have ratites, or did have until the fairly recent past. So did Europe in the Paleocene and Eocene , from where the first flightless paleognaths are known. Ostriches were present in Asia as recently as the Holocene , although the genus is thought to have originated in Africa. However,
1470-711: A waste product of poultry farming, including chickens , geese , turkeys , pheasants , and ostriches . These feathers are dyed and manipulated to enhance their appearance, as poultry feathers are naturally often dull in appearance compared to the feathers of wild birds. Feather derives from the Old English "feþer", which is of Germanic origin; related to Dutch "veer" and German "Feder", from an Indo-European root shared by Sanskrit's "patra" meaning 'wing', Latin's "penna" meaning 'feather', and Greek's "pteron", "pterux" meaning 'wing'. Because of feathers being an integral part of quills , which were early pens used for writing,
1568-567: A whole probably had an origin in the northern hemisphere. Early Cenozoic northern hemisphere paleognaths such as Lithornis , Pseudocrypturus , Paracathartes and Palaeotis appear to be the most basal members of the clade. The various ratite lineages were probably descended from flying ancestors that independently colonised South America and Africa from the north, probably initially in South America. From South America they could have traveled overland to Australia via Antarctica, (by
1666-438: Is a stub . You can help Misplaced Pages by expanding it . Ratite Tinamiformes Ratites ( / ˈ r æ t aɪ t s / ) are a polyphyletic group consisting of all birds within the infraclass Palaeognathae that lack keels and cannot fly . They are mostly large, long-necked, and long-legged, the exception being the kiwi , which is also the only nocturnal extant ratite. The understanding of relationships within
1764-402: Is actually more closely related to Ornithischia , to which it formed the sister group within the clade Ornithoscelida . The study also suggested that if the feather-like structures of theropods and ornithischians are of common evolutionary origin then it would be possible that feathers were restricted to Ornithoscelida. If so, then the origin of feathers would have likely occurred as early as
1862-437: Is also very difficult to clean and rescue birds whose feathers have been fouled by oil spills . The feathers of cormorants soak up water and help to reduce buoyancy, thereby allowing the birds to swim submerged. Bristles are stiff, tapering feathers with a large rachis but few barbs. Rictal bristles are found around the eyes and bill. They may serve a similar purpose to eyelashes and vibrissae in mammals . Although there
1960-435: Is as yet no clear evidence, it has been suggested that rictal bristles have sensory functions and may help insectivorous birds to capture prey. In one study, willow flycatchers ( Empidonax traillii ) were found to catch insects equally well before and after removal of the rictal bristles. Grebes are peculiar in their habit of ingesting their own feathers and feeding them to their young. Observations on their diet of fish and
2058-442: Is commonplace. Struthionidae (ostriches, 2 spp.) Rheidae (rheas, 2~3 spp.) † Dinornithiformes (moa) Tinamidae (tinamous, 46 spp.) † Aepyornithidae (elephant birds) Apterygidae (kiwi, 5 spp.) Casuariidae (cassowaries, 3 spp.) Dromaiidae (emus, 1 sp.) By 2014, a mitochondrial DNA phylogeny including fossil members placed ostriches on the basal branch, followed by rheas, then
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#17327762765952156-566: Is considered presumptuous. During the 18th, 19th, and early 20th centuries, there was a booming international trade in plumes for extravagant women's hats and other headgear (including in Victorian fashion ). Frank Chapman noted in 1886 that feathers of as many as 40 species of birds were used in about three-fourths of the 700 ladies' hats that he observed in New York City. For instance, South American hummingbird feathers were used in
2254-501: Is currently lacking. Ratite chicks tend to be more omnivorous or insectivorous ; similarities in adults end with feeding, as they all vary in diet and length of digestive tract, which is indicative of diet. Ostriches, with the longest tracts at 14 m (46 ft), are primarily herbivorous . Rheas' tracts are next longest at 8–9 m (26–30 ft), and they also have caeca . They are also mainly herbivores , concentrating on broad-leafed plants. However, they will eat insects if
2352-477: The Indian peacock have been used in traditional medicine for snakebite, infertility, and coughs. Members of Scotland's Clan Campbell are known to wear feathers on their bonnets to signify authority within the clan. Clan chiefs wear three, chieftains wear two and an armiger wears one. Any member of the clan who does not meet the criteria is not authorized to wear feathers as part of traditional garb and doing so
2450-463: The K–Pg extinction event created a window of time with large predators absent that may have allowed the ancestors of extant flightless ratites to evolve flightlessness. They subsequently underwent selection for large size. One hypothesis suggests that as predation pressure decreases on islands with low raptor species richness and no mammalian predators, the need for large, powerful flight muscles that make for
2548-467: The Middle Triassic , though this has been disagreed upon. The lack of feathers present in large sauropods and ankylosaurs could be that feathers were suppressed by genomic regulators. Several studies of feather development in the embryos of modern birds, coupled with the distribution of feather types among various prehistoric bird precursors, have allowed scientists to attempt a reconstruction of
2646-626: The United States and First Nations peoples in Canada as religious objects. In the United States, the religious use of eagle and hawk feathers is governed by the eagle feather law , a federal law limiting the possession of eagle feathers to certified and enrolled members of federally recognized Native American tribes. In South America, brews made from the feathers of condors are used in traditional medications. In India, feathers of
2744-441: The gastrodermis , which forms a boundary with the epidermis at the mouth. Sponges have no epithelium, and therefore no epidermis or gastrodermis. The epidermis of a more complex invertebrate is just one layer deep, and may be protected by a non-cellular cuticle . The epidermis of a higher vertebrate has many layers, and the outer layers are reinforced with keratin and then die. This animal anatomy –related article
2842-491: The ornithischian dinosaurs Tianyulong and Psittacosaurus . The exact nature of these structures is still under study. However, it is believed that the stage-1 feathers (see Evolutionary stages section below) such as those seen in these two ornithischians likely functioned in display. In 2014, the ornithischian Kulindadromeus was reported as having structures resembling stage-3 feathers. The likelihood of scales evolving on early dinosaur ancestors are high. However, this
2940-480: The sexual dimorphism of many bird species and are particularly important in the selection of mating pairs. In some cases, there are differences in the UV reflectivity of feathers across sexes even though no differences in color are noted in the visible range. The wing feathers of male club-winged manakins Machaeropterus deliciosus have special structures that are used to produce sounds by stridulation . Some birds have
3038-542: The α-keratins of mammalian hair , horns and hooves . The exact signals that induce the growth of feathers on the skin are not known, but it has been found that the transcription factor cDermo-1 induces the growth of feathers on skin and scales on the leg. There are two basic types of feather: vaned feathers which cover the exterior of the body, and down feathers which are underneath the vaned feathers. The pennaceous feathers are vaned feathers. Also called contour feathers, pennaceous feathers arise from tracts and cover
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3136-491: The 18th century, which led to hunting and sharp declines in populations. Ostrich farming grew out of this need, and humans harvested feathers, hides, eggs, and meat from the ostrich. Emu farming also became popular for similar reasons and for their emu oil . Rhea feathers are popular for dusters, and eggs and meat are used for chicken and pet feed in South America. Ratite hides are popular for leather products like shoes. The USDA's Food Safety and Inspection Service (FSIS) began
3234-635: The Australian emu is next in height, reaching up to 1.9 metres (6 ft 3 in) tall and about 50 kilograms (110 lb). Like the ostrich, it is a fast-running, powerful bird of the open plains and woodlands . Also native to Australia and the islands to the north are the three species of cassowary . Shorter than an emu, but heavier and solidly built, cassowaries prefer thickly vegetated tropical forest. They can be dangerous when surprised or cornered because of their razor-sharp talons . In New Guinea , cassowary eggs are brought back to villages and
3332-464: The Middle Eocene ratites such as Palaeotis and Remiornis from Central Europe may imply that the "out-of-Gondwana" hypothesis is oversimplified. Molecular phylogenies of the ratites have generally placed ostriches in the basal position and among extant ratites, placed rheas in the second most basal position, with Australo-Pacific ratites splitting up last; they have also shown that both
3430-485: The New Zealand kiwi. Additional support for the latter relationship was obtained from morphological analysis. The finding that tinamous nest within this group, originally based on twenty nuclear genes and corroborated by a study using forty novel nuclear loci makes 'ratites' polyphyletic rather than monophyletic, if we exclude the tinamous. Since tinamous are weak fliers, this raises interesting questions about
3528-449: The ability to expand from a compressed, stored state to trap large amounts of compartmentalized, insulating air. Feathers of large birds (most often geese ) have been and are used to make quill pens. Historically, the hunting of birds for decorative and ornamental feathers has endangered some species and helped to contribute to the extinction of others. Today, feathers used in fashion and in military headdresses and clothes are obtained as
3626-526: The ancestors of ratites, were present and widespread in Gondwana during the Late Cretaceous. As the supercontinent fragmented due to plate tectonics , they were carried by plate movements to their current positions and evolved into the species present today. The earliest known ratite fossils date to the Paleocene epoch about 56 million years ago (e.g., Diogenornis , a possible early relative of
3724-414: The ancestral state of dinosaurs. In 2010, a carcharodontosaurid named Concavenator corcovatus was found to have remiges on the ulna suggesting it might have had quill-like structures on the ams. However, Foth et al. 2014 disagress with the publication where they point out that the bumps on the ulna of Concavenator are on the anterolateral which is unlike remiges which are in a posterolateral on
3822-491: The apterylae. The arrangement of these feather tracts, pterylosis or pterylography, varies across bird families and has been used in the past as a means for determining the evolutionary relationships of bird families. Species that incubate their own eggs often lose their feathers on a region of their belly, forming a brooding patch . The colors of feathers are produced by pigments, by microscopic structures that can refract , reflect, or scatter selected wavelengths of light, or by
3920-406: The arrival of humans, ranging from turkey-sized to the giant moa Dinornis robustus with a height of 3.7 metres (12 ft 2 in) and weighing about 230 kilograms (510 lb). They became extinct by A.D. 1400 due to hunting by Māori settlers, who arrived around A.D. 1280. Aepyornis maximus , the "elephant bird" of Madagascar , was the heaviest bird ever known. Although shorter than
4018-405: The barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular calamus (or quill ) which inserts into a follicle in the skin . The basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base (proximal umbilicus) and
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4116-678: The bird's body, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, and waterproofing. In addition, coloration helps in communication and protection . The study of feathers is called plumology (or plumage science ). People use feathers in many ways that are practical, cultural, and religious. Feathers are both soft and excellent at trapping heat ; thus, they are sometimes used in high-class bedding , especially pillows , blankets , and mattresses . They are also used as filling for winter clothing and outdoor bedding, such as quilted coats and sleeping bags . Goose and eider down have great loft ,
4214-594: The case of green plumage, in addition to yellow, the specific feather structure involved is called by some the Dyck texture. Melanin is often involved in the absorption of light; in combination with a yellow pigment, it produces a dull olive-green. In some birds, feather colors may be created, or altered, by secretions from the uropygial gland , also called the preen gland. The yellow bill colors of many hornbills are produced by such secretions. It has been suggested that there are other color differences that may be visible only in
4312-536: The chicks raised for eating as a much-prized delicacy, despite (or perhaps because of) the risk they pose to life and limb. They reach up to 1.8 metres (5 ft 11 in) tall and weigh as much as 85 kilograms (187 lb) South America has two species of rhea , large fast-running birds of the Pampas . The larger American rhea grows to about 1.4 metres (4 ft 7 in) tall and usually weighs 15 to 40 kilograms (33–88 lb). The smallest ratites are
4410-510: The color and pattern of the feathers on Anchiornis and Tupandactylus could be determined. Anchiornis was found to have black-and-white-patterned feathers on the forelimbs and hindlimbs, with a reddish-brown crest. This pattern is similar to the coloration of many extant bird species, which use plumage coloration for display and communication, including sexual selection and camouflage. It is likely that non-avian dinosaur species utilized plumage patterns for similar functions as modern birds before
4508-420: The darker birds confirmed Gloger's rule . Although sexual selection plays a major role in the development of feathers, in particular, the color of the feathers it is not the only conclusion available. New studies are suggesting that the unique feathers of birds are also a large influence on many important aspects of avian behavior, such as the height at which different species build their nests. Since females are
4606-425: The elephant bird–kiwi relation appears to require dispersal across oceans by flight, as apparently does the colonization of New Zealand by the moa and possibly the back-dispersal of tinamous to South America, if the latter occurred. The phylogeny as a whole suggests not only multiple independent origins of flightlessness, but also of gigantism (at least five times). Gigantism in birds tends to be insular ; however,
4704-422: The entire body. A third rarer type of feather, the filoplume , is hairlike and are closely associated with pennaceous feathers and are often entirely hidden by them, with one or two filoplumes attached and sprouting from near the same point of the skin as each pennaceous feather, at least on a bird's head, neck and trunk. Filoplumes are entirely absent in ratites . In some passerines, filoplumes arise exposed beyond
4802-505: The evolution of feathers—theropods with highly derived bird-like characteristics occurred at a later time than Archaeopteryx —suggesting that the descendants of birds arose before the ancestor. However, the discovery of Anchiornis huxleyi in the Late Jurassic Tiaojishan Formation (160 MYA) in western Liaoning in 2009 resolved this paradox. By predating Archaeopteryx , Anchiornis proves the existence of
4900-454: The evolution of flightlessness in this group. The branching of the tinamous within the ratite radiation suggests flightlessness evolved independently among ratites at least three times. More recent evidence suggests this happened at least six times, or once in each major ratite lineage. Re-evolution of flight in the tinamous would be an alternative explanation, but such a development is without precedent in avian history, while loss of flight
4998-611: The evolution of proto-birds like Archaeopteryx and Microraptor zhaoianus . Another theory posits that the original adaptive advantage of early feathers was their pigmentation or iridescence, contributing to sexual preference in mate selection. Dinosaurs that had feathers or protofeathers include Pedopenna daohugouensis and Dilong paradoxus , a tyrannosauroid which is 60 to 70 million years older than Tyrannosaurus rex . The majority of dinosaurs known to have had feathers or protofeathers are theropods , however featherlike "filamentous integumentary structures" are also known from
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#17327762765955096-429: The exception with extended monogamous reproductive strategies where either the male alone or both sexes incubate a single egg. Unlike most birds, male ratites have a phallus that is inserted into the female's cloaca during copulation . Ratites and humans have had a long relationship starting with the use of the egg for water containers, jewelry, or other art medium. Male ostrich feathers were popular for hats during
5194-536: The expense of health. A bird's feathers undergo wear and tear and are replaced periodically during the bird's life through molting . New feathers, known when developing as blood, or pin feathers , depending on the stage of growth, are formed through the same follicles from which the old ones were fledged. The presence of melanin in feathers increases their resistance to abrasion. One study notes that melanin based feathers were observed to degrade more quickly under bacterial action, even compared to unpigmented feathers from
5292-417: The face that were used as tactile sensors. While feathers have been suggested as having evolved from reptilian scales , there are numerous objections to that idea, and more recent explanations have arisen from the paradigm of evolutionary developmental biology . Theories of the scale-based origins of feathers suggest that the planar scale structure was modified for development into feathers by splitting to form
5390-651: The family Tinamidae , or tinamous. First, the breast muscles are underdeveloped. They do not have keeled sterna . Their wishbones ( furculae ) are almost absent. They have simplified wing skeletons and musculature. Their legs are stronger and do not have air chambers, except the femurs . Their tail and flight feathers have retrogressed or have become decorative plumes. They have no feather vanes, which means they do not need to oil their feathers, hence they have no preen glands . They have no separation of pterylae (feathered areas) and apteria (non-feathered areas), and finally, they have palaeognathous palates . Ostriches have
5488-408: The feathers of extant diving birds – in 80 million year old amber from Alberta. Two small wings trapped in amber dating to 100 mya show plumage existed in some bird predecessors. The wings most probably belonged to enantiornithes , a diverse group of avian dinosaurs. A large phylogenetic analysis of early dinosaurs by Matthew Baron, David B. Norman and Paul Barrett (2017) found that Theropoda
5586-406: The fibers are better aligned along the shaft axis direction towards the tip, and the lateral walls of rachis region show structure of crossed fibers. Feathers insulate birds from water and cold temperatures. They may also be plucked to line the nest and provide insulation to the eggs and young. The individual feathers in the wings and tail play important roles in controlling flight. Some species have
5684-580: The five species of kiwi from New Zealand. Kiwi are chicken -sized, shy, and nocturnal . They nest in deep burrows and use a highly developed sense of smell to find small insects and grubs in the soil. Kiwi are notable for laying eggs that are very large in relation to their body size. A kiwi egg may equal 15 to 20 percent of the body mass of a female kiwi. The smallest species of kiwi is the little spotted kiwi , at 0.9 to 1.9 kilograms (2.0–4.2 lb) and 35 to 45 centimetres (14–18 in). At least nine species of moa lived in New Zealand before
5782-501: The frequency of feather eating suggest that ingesting feathers, particularly down from their flanks, aids in forming easily ejectable pellets. Contour feathers are not uniformly distributed on the skin of the bird except in some groups such as the penguins , ratites and screamers. In most birds the feathers grow from specific tracts of skin called pterylae ; between the pterylae there are regions which are free of feathers called apterylae (or apteria ). Filoplumes and down may arise from
5880-866: The greatest dimorphism , rheas show some dichromatism during the breeding season. Emus, cassowaries, and kiwis show some dimorphism, predominantly in size. While the ratites share a lot of similarities, they also have major differences. Ostriches have only two toes, with one being much larger than the other. Cassowaries have developed long inner toenails, used defensively. Ostriches and rheas have prominent wings; although they do not use them to fly, they do use them in courtship and predator distraction. Without exception, ratite chicks are capable of swimming and even diving. On an allometric basis, paleognaths have generally smaller brains than neognaths . Kiwis are exceptions to this trend, and possess proportionally larger brains comparable to those of parrots and songbirds , though evidence for similar advanced cognitive skills
5978-739: The groups as families in the order Struthioniformes , while the other supposes that the lineages evolved mostly independently and thus elevates the families to order rank ( Rheiformes , Casuariformes etc.). The longstanding story of ratite evolution was that they share a common flightless ancestor that lived in Gondwana , whose descendants were isolated from each other by continental drift , which carried them to their present locations. Supporting this idea, some studies based on morphology, immunology and DNA sequencing reported that ratites are monophyletic . Cracraft's 1974 biogeographic vicariance hypothesis suggested that ancestral flightless paleognaths,
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#17327762765956076-425: The identification of species in forensic studies, particularly in bird strikes to aircraft. The ratios of hydrogen isotopes in feathers help in determining the geographic origins of birds. Feathers may also be useful in the non-destructive sampling of pollutants. The poultry industry produces a large amount of feathers as waste, which, like other forms of keratin, are slow to decompose. Feather waste has been used in
6174-505: The incubating duties with others. Ostriches, and great spotted kiwis, are the only ratites where the female incubates; they share the duties, with the males incubating at night. Cassowaries and emu are polyandrous, with males incubating eggs and rearing chicks with no obvious contribution from females. Ostriches and rheas are polygynous with each male courting several females. Male rheas are responsible for building nests and incubating while ostrich males incubate only at night. Kiwis stand out as
6272-622: The latter groups are monophyletic. Early mitochondrial genetic studies that failed to make ostriches basal were apparently compromised by the combination of rapid early radiation of the group and long terminal branches. A morphological analysis that created a basal New Zealand clade has not been corroborated by molecular studies. A 2008 study of nuclear genes shows ostriches branching first, followed by rheas and tinamous, then kiwi splitting from emus and cassowaries. In more recent studies, moas and tinamous were shown to be sister groups , and elephant birds were shown to be most closely related to
6370-570: The latter's case. Some extinct ratites might have had odder lifestyles, such as the narrow-billed Diogenornis and Palaeotis , compared to the shorebird-like lithornithids , and could imply similar animalivorous diets. Ratites are different from the flying birds in that they needed to adapt or evolve certain features to protect their young. First and foremost is the thickness of the shells of their eggs. Their young are hatched more developed than most and they can run or walk soon thereafter. Also, most ratites have communal nests, where they share
6468-453: The name, from the Latin ratis (' raft ', a vessel which has no keel — in contradistinction to extant flighted birds with a keel). Without this to anchor their wing muscles, they could not have flown even if they had developed suitable wings. Ratites are a polyphyletic group; tinamous fall within them, and are the sister group of the extinct moa . This implies that flightlessness is
6566-581: The nest. The height study found that birds that nest in the canopies of trees often have many more predator attacks due to the brighter color of feathers that the female displays. Another influence of evolution that could play a part in why feathers of birds are so colorful and display so many patterns could be due to that birds developed their bright colors from the vegetation and flowers that thrive around them. Birds develop their bright colors from living around certain colors. Most bird species often blend into their environment, due to some degree of camouflage, so if
6664-619: The nests of other species also have host-specific feather lice and these seem to be transmitted only after the young cuckoos leave the host nest. Birds maintain their feather condition by preening and bathing in water or dust . It has been suggested that a peculiar behavior of birds, anting , in which ants are introduced into the plumage, helps to reduce parasites, but no supporting evidence has been found. Bird feathers have long been used for fletching arrows . Colorful feathers such as those belonging to pheasants have been used to decorate fishing lures . Feathers are also valuable in aiding
6762-512: The only land mass to recently support two major lineages of flightless ratites may reflect the near total absence of native mammals, which allowed kiwi to occupy a mammal-like nocturnal niche . However, various other landmasses such as South America and Europe have supported multiple lineages of flightless ratites that evolved independently, undermining this competitive exclusion hypothesis. Most recently, studies on genetic and morphological divergence and fossil distribution show that paleognaths as
6860-450: The opportunity arises. Emus have tracts of 7 m (23 ft) length, and have a more omnivorous diet, including insects and other small animals. Cassowaries have next to the shortest tracts at 4 m (13 ft). Finally, kiwi have the shortest tracts and eat earthworms, insects, and other similar creatures. Moas and elephant birds were the largest native herbivores in their faunas, far larger than contemporary herbivorous mammals in
6958-432: The origin of flight. In many cases, the physiological condition of the birds (especially males) is indicated by the quality of their feathers, and this is used (by the females) in mate choice . Additionally, when comparing different Ornithomimus edmontonicus specimens, older individuals were found to have a pennibrachium (a wing-like structure consisting of elongate feathers), while younger ones did not. This suggests that
7056-457: The original primary function as the feathers simply would not have been capable of providing any form of lift. There have been suggestions that feathers may have had their original function in thermoregulation, waterproofing, or even as sinks for metabolic wastes such as sulphur. Recent discoveries are argued to support a thermoregulatory function, at least in smaller dinosaurs. Some researchers even argue that thermoregulation arose from bristles on
7154-529: The ostrich order may have evolved in Eurasia. A recent study posits a Laurasian origin for the clade. Geranoidids , which may have been ratites, existed in North America. The African ostrich is the largest living ratite. A large member of this species can be nearly 2.8 metres (9 ft 2 in) tall, weigh as much as 156 kilograms (344 lb), and can outrun a horse. Of the living species,
7252-412: The paleognath clade has been in flux. Previously, all the flightless members had been assigned to the order Struthioniformes , which is more recently regarded as containing only the ostrich . The modern bird superorder Palaeognathae consists of ratites and the flighted Neotropic tinamous (compare to Neognathae ). Unlike other flightless birds, the ratites have no keel on their sternum — hence
7350-462: The parasite species being specific to the host and coevolving with the host, making them of interest in phylogenetic studies. Feather holes are chewing traces of lice (most probably Brueelia spp. lice) on the wing and tail feathers. They were described on barn swallows , and because of easy countability, many evolutionary, ecological, and behavioral publications use them to quantify the intensity of infestation. Parasitic cuckoos which grow up in
7448-490: The past to dress some of the miniature birds featured in singing bird boxes . This trade caused severe losses to bird populations (for example, egrets and whooping cranes ). Conservationists led a major campaign against the use of feathers in hats. This contributed to passage of the Lacey Act in 1900, and to changes in fashion. The ornamental feather market then largely collapsed. More recently, rooster plumage has become
7546-546: The pennaceous feathers of Anchiornis were not made of the feather β-keratins present in extant birds. However, a study of fossil feathers from the dinosaur Sinosauropteryx and other fossils revealed traces of beta-sheet proteins, using infrared spectroscopy and sulfur-X-ray spectroscopy. The presence of abundant alpha-proteins in some fossil feathers was shown to be an artefact of the fossilization process, as beta-protein structures are readily altered to alpha-helices during thermal degradation. In 2019, scientists found that genes for
7644-495: The pennaceous feathers on the neck. The remiges, or flight feathers of the wing, and rectrices, or flight feathers of the tail, are the most important feathers for flight. A typical vaned feather features a main shaft, called the rachis . Fused to the rachis are a series of branches, or barbs ; the barbs themselves are also branched and form the barbules . These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so
7742-494: The pennibrachium was a secondary sex characteristic and likely had a sexual function. Several genes have been found to determine feather development. They will be key to understand the evolution of feathers. For instance, some genes convert scales into feathers or feather-like structures when expressed or induced in bird feet, such as the scale-feather converters Sox2 , Zic1 , Grem1 , Spry2 , and Sox18 . Feathers and scales are made up of two distinct forms of keratin , and it
7840-411: The pigeons and parrots or in localized patches on the breast, belly, or flanks, as in herons and frogmouths. Herons use their bill to break the powder down feathers and to spread them, while cockatoos may use their head as a powder puff to apply the powder. Waterproofing can be lost by exposure to emulsifying agents due to human pollution. Feathers can then become waterlogged, causing the bird to sink. It
7938-431: The prime caregivers, evolution has helped select females to display duller colors down so that they may blend into the nesting environment. The position of the nest and whether it has a greater chance of being under predation has exerted constraints on female birds' plumage. A species of bird that nests on the ground, rather than the canopy of the trees, will need to have much duller colors in order not to attract attention to
8036-607: The production of blue colors, iridescence , most ultraviolet reflectance and in the enhancement of pigmentary colors. Structural iridescence has been reported in fossil feathers dating back 40 million years. White feathers lack pigment and scatter light diffusely; albinism in birds is caused by defective pigment production, though structural coloration will not be affected (as can be seen, for example, in blue-and-white budgerigars ). The blues and bright greens of many parrots are produced by constructive interference of light reflecting from different layers of structures in feathers. In
8134-479: The production of feathers evolved at the base of archosauria, supporting that feathers were present at early ornithodirans and is consistent with the fossil record. Several non-avian dinosaurs had feathers on their limbs that would not have functioned for flight. One theory suggests that feathers originally evolved on dinosaurs due to their insulation properties; then, small dinosaur species which grew longer feathers may have found them helpful in gliding, leading to
8232-465: The rachis and herringbone pattern of the barbs. In the clade Deinonychosauria, the continued divergence of feathers is also apparent in the families Troodontidae and Dromaeosauridae . Branched feathers with rachis, barbs, and barbules were discovered in many members including Sinornithosaurus millenii , a dromaeosaurid found in the Yixian formation (124.6 MYA). Previously, a temporal paradox existed in
8330-652: The recent common ancestors of birds, Oviraptorosauria and Deinonychosauria . In 1998, the discovery of a feathered oviraptorosaurian, Caudipteryx zoui , challenged the notion of feathers as a structure exclusive to Avialae. Buried in the Yixian Formation in Liaoning, China, C. zoui lived during the Early Cretaceous Period. Present on the forelimbs and tails, their integumentary structure has been accepted as pennaceous vaned feathers based on
8428-471: The rhea). However, more primitive paleognaths are known from several million years earlier, and the classification and membership of the Ratitae itself is uncertain. Some of the earliest ratites occur in Europe. Recent analyses of genetic variation between the ratites do not support this simple picture. The ratites may have diverged from one another too recently to share a common Gondwanan ancestor. Also,
8526-460: The same route marsupials are thought to have used to reach Australia ) and then reached New Zealand and Madagascar via "sweepstakes" dispersals (rare low probability dispersal methods, such as long distance rafting) across the oceans. Gigantism would have evolved subsequent to trans-oceanic dispersals. Loss of flight allows birds to eliminate the costs of maintaining various flight-enabling adaptations like high pectoral muscle mass, hollow bones and
8624-412: The same species, than those unpigmented or with carotenoid pigments. However, another study the same year compared the action of bacteria on pigmentations of two song sparrow species and observed that the darker pigmented feathers were more resistant; the authors cited other research also published in 2004 that stated increased melanin provided greater resistance. They observed that the greater resistance of
8722-418: The sequence in which feathers first evolved and developed into the types found on modern birds. Feather evolution was broken down into the following stages by Xu and Guo in 2009: Epidermis (zoology) In zoology, the epidermis is an epithelium (sheet of cells ) that covers the body of a eumetazoan ( animal more complex than a sponge ). Eumetazoa have a cavity lined with a similar epithelium,
8820-534: The species habitat is full of colors and patterns, the species would eventually evolve to blend in to avoid being eaten. Birds' feathers show a large range of colors, even exceeding the variety of many plants, leaf, and flower colors. The feather surface is the home for some ectoparasites, notably feather lice ( Phthiraptera ) and feather mites. Feather lice typically live on a single host and can move only from parents to chicks, between mating birds, and, occasionally, by phoresy . This life history has resulted in most of
8918-500: The tallest moa, a large A. maximus could weigh over 400 kilograms (880 lb) and stand up to 3 metres (9 ft 10 in) tall. Accompanying it were three other species of Aepyornis as well as three species of the smaller genus Mullerornis . All these species went into decline following the arrival of humans on Madagascar around 2,000 years ago, and were gone by the 17th or 18th century if not earlier. There are two taxonomic approaches to ratite classification: one combines
9016-410: The ulna of some birds, they consider it more likely that these are attachments for interosseous ligaments. This was refuted by Cuesta Fidalgo and her colleagues, they pointed out that these bumps on the ulna are posterolateral which is unlike that of interosseous ligaments. Since the 1990s, dozens of feathered dinosaurs have been discovered in the clade Maniraptora , which includes the clade Avialae and
9114-492: The ultraviolet region, but studies have failed to find evidence. The oil secretion from the uropygial gland may also have an inhibitory effect on feather bacteria. The reds, orange and yellow colors of many feathers are caused by various carotenoids. Carotenoid-based pigments might be honest signals of fitness because they are derived from special diets and hence might be difficult to obtain, and/or because carotenoids are required for immune function and hence sexual displays come at
9212-477: The webbing; however, that developmental process involves a tubular structure arising from a follicle and the tube splitting longitudinally to form the webbing. The number of feathers per unit area of skin is higher in smaller birds than in larger birds, and this trend points to their important role in thermal insulation, since smaller birds lose more heat due to the relatively larger surface area in proportion to their body weight. The miniaturization of birds also played
9310-674: The word pen itself is derived from the Latin penna , meaning feather. The French word plume can mean feather , quill , or pen . Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis , or outer skin layer, that produce keratin proteins . The β-keratins in feathers, beaks and claws – and the claws, scales and shells of reptiles – are composed of protein strands hydrogen-bonded into β-pleated sheets , which are then further twisted and crosslinked by disulfide bridges into structures even tougher than
9408-509: Was by assuming that primitive pterosaurs were scaly. A 2016 study analyzes the pulp morphology of the tail bristles of Psittacosaurus and finds they are similar to feathers but notes that they are also similar to the bristles on the head of the Congo peafowl , the beard of the turkey , and the spine on the head of the horned screamer . A reestimation of maximum likelihoods by paleontologist Thomas Holtz finds that filaments were more likely to be
9506-436: Was inherited from a common ancestor. This may suggest that crocodilian scales, bird and dinosaur feathers, and pterosaur pycnofibres are all developmental expressions of the same primitive archosaur skin structures; suggesting that feathers and pycnofibers could be homologous. Molecular dating methods in 2011 show that the subfamily of feather β-keratins found in extant birds started to diverge 143 million years ago, suggesting
9604-494: Was long thought that each type of keratin was exclusive to each skin structure (feathers and scales). However, feather keratin is also present in the early stages of development of American alligator scales. This type of keratin, previously thought to be specific to feathers, is suppressed during embryological development of the alligator and so is not present in the scales of mature alligators. The presence of this homologous keratin in both birds and crocodilians indicates that it
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