44-409: The Anatidae are the biological family of water birds that includes ducks , geese , and swans . The family has a cosmopolitan distribution , occurring on all the world's continents except Antarctica. These birds are adapted for swimming , floating on the water surface, and, in some cases, diving in at least shallow water. The family contains around 174 species in 43 genera (the magpie goose
88-658: A broad and elongated general body plan. Diving species vary from this in being rounder. Extant species range in size from the cotton pygmy goose , at as little as 26.5 cm (10.5 in) and 164 g (5.8 oz), to the trumpeter swan , at as much as 183 cm (6 ft) and 17.2 kg (38 lb). The largest anatid ever known is the extinct flightless Garganornis ballmanni at 22 kg (49 lb). The wings are short and pointed, and supported by strong wing muscles that generate rapid beats in flight . They typically have long necks, although this varies in degree between species. The legs are short, strong, and set far to
132-412: A family— or whether a described family should be acknowledged— is established and decided upon by active taxonomists . There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to
176-554: A lack of widespread consensus within the scientific community for extended periods. The continual publication of new data and diverse opinions plays a crucial role in facilitating adjustments and ultimately reaching a consensus over time. The naming of families is codified by various international bodies using the following suffixes: The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called
220-411: A layer of sand that provides both protection from predators and a constant temperature for the nest. Snakes may lay eggs in communal burrows, where a large number of adults combine to keep the eggs warm. Some species coil their torsos around the eggs to provide heat for incubation. Alligators and crocodiles either lay their eggs in mounds of decomposing vegetation or lay them in holes they dig in
264-483: A new partner the following year, whereas the larger swans, geese and some of the more territorial ducks maintain pair bonds over a number of years, and even for life in some species. However, forced extrapair copulation among anatids is common, occurring in 55 species in 17 genera. Anatidae is a large proportion of the 3% of bird species to possess a penis , though they vary significantly in size, shape, and surface elaboration. Most species are adapted for copulation on
308-706: A number of other ducks occasionally lay eggs in the nests of conspecifics (members of the same species) in addition to raising their own broods. Duck, eider, and goose feathers and down have long been popular for bedspreads, pillows, sleeping bags, and coats. The members of this family also have long been used for food. Humans have had a long relationship with ducks, geese, and swans; they are important economically and culturally to humans, and several duck species have benefited from an association with people. However, some anatids are agricultural pests , and have acted as vectors for zoonoses such as avian influenza . Since 1600, five species of ducks have become extinct due to
352-404: A thin and sensitive layer of skin on top (which has a leathery feel when touched). For most species, the shape of the bill tends to be more flattened to a greater or lesser extent. These contain serrated lamellae which are particularly well defined in the filter-feeding species. Their feathers are excellent at shedding water due to special oils. Many of the ducks display sexual dimorphism , with
396-431: Is classified between order and genus . A family may be divided into subfamilies , which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae , but that family is commonly referred to as the "walnut family". The delineation of what constitutes
440-415: Is displayed among birds. In warm-blooded species such as bird species generally, body heat from the brooding patch of the brooding parent provides the constant temperature. Several groups, notably the megapodes , instead use heat generated from rotting vegetable material, effectively creating a giant compost heap, while crab plovers make partial use of heat from the sun. The Namaqua sandgrouse of
484-544: Is no longer considered to be part of the Anatidae and is now placed in its own family, Anseranatidae ). They are generally herbivorous and are monogamous breeders. A number of species undertake annual migrations . A few species have been domesticated for agriculture, and many others are hunted for food and recreation. Five species have become extinct since 1600, and many more are threatened with extinction . The ducks, geese, and swans are small- to large-sized birds with
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#1732773209863528-608: Is small, mtDNA results must be considered with caution. While a comprehensive review of the Anatidae which unites all evidence into a robust phylogeny is still lacking, the reasons for the confusing data are at least clear: As demonstrated by the Late Cretaceous fossil Vegavis iaai —an early modern waterbird which belonged to an extinct lineage—the Anatidae are an ancient group among the modern birds. Their earliest direct ancestors, though not documented by fossils yet, likewise can be assumed to have been contemporaries with
572-549: The Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family. Families serve as valuable units for evolutionary, paleontological, and genetic studies due to their relatively greater stability compared to lower taxonomic levels like genera and species. Avian incubation Egg incubation is the process by which an egg , of oviparous (egg-laying) animals, develops an embryo within
616-519: The archipelago contains as Anseriformes Branta geese and their descendants, and the moa-nalos as mentioned above. The following taxa, although certainly new species, cannot be assigned even to subfamily; that Kauaʻi is the oldest of the large Hawaiian Islands, meaning the species may have been evolving in isolation for nearly 10 mya (since the Late Miocene ), does not help in determining their affinities: Similarly, Branta rhuax from
660-448: The brown kiwi ). In these latter, the incubation is interrupted; the longest uninterrupted period is 64 to 67 days in the emperor penguin . In general smaller birds tend to hatch faster, but there are exceptions, and cavity nesting birds tend to have longer incubation periods. It can be an energetically demanding process, with adult albatrosses losing as much as 83 g of body weight a day. Megapode eggs take from 49 to 90 days depending on
704-582: The family was introduced by the English zoologist William Elford Leach in a guide to the contents of the British Museum published in 1819. While the status of the Anatidae as a family is straightforward, and which species properly belong to it is little debated, the relationships of the different tribes and subfamilies within it are poorly understood. The listing in the box at right should be regarded as simply one of several possible ways of organising
748-419: The mergansers , are primarily piscivorous , and have serrated bills to help them catch fish. In a number of species, the young include a high proportion of invertebrates in their diets, but become purely herbivorous as adults. The anatids are generally seasonal and monogamous breeders. The level of monogamy varies within the family; many of the smaller ducks only maintain the bond for a single season and find
792-633: The Anatidae may be considered to consist of three subfamilies (ducks, geese, and swans, essentially) which contain the groups as presented here as tribes , with the swans separated as subfamily Cygninae , the goose subfamily Anserinae also containing the whistling ducks, and the Anatinae containing all other clades . For the living and recently extinct members of each genus, see the article List of Anatidae species . From subfossil bones found on Kauaʻi ( Hawaiian Islands ), two enigmatic waterfowl are known. The living and assignable prehistoric avifauna of
836-473: The Big Island of Hawaiʻi , and a gigantic goose-like anatid from Oʻahu are known only from very incomplete, and in the former case much damaged, bone fragments. The former has been alleged to be a shelduck, but this was generally dismissed because of the damage to the material and biogeographic considerations. The long-legged Kauaʻi bird, however, hints at the possibility of a former tadornine presence on
880-623: The ability to fly, and were vulnerable to human hunting pressure and introduced species . Other extinctions and declines are attributable to overhunting, habitat loss and modification, and hybridisation with introduced ducks (for example the introduced ruddy duck swamping the white-headed duck in Europe). Numerous governments and conservation and hunting organisations have made considerable progress in protecting ducks and duck populations through habitat protection and creation, laws and protection, and captive-breeding programmes. The name Anatidae for
924-425: The activities of humans, and subfossil remains have shown that humans caused numerous extinctions in prehistory. Today, many more are considered threatened . Most of the historic and prehistoric extinctions were insular species, vulnerable due to small populations (often endemic to a single island), and island tameness . Evolving on islands that lacked predators, these species lost antipredator behaviours, as well as
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#1732773209863968-731: The archipelago. The fossil record of anatids is extensive, but many prehistoric genera cannot be unequivocally assigned to present-day subfamilies for the reasons given above. For prehistoric species of extant genera, see the respective genus accounts. Dendrocheninae – a more advanced relative of the whistling-ducks or an ancestral relative of stifftail ducks paralleling whistling-ducks; if not extinct possibly belong in Oxyurinae (including Malacorhynchus ) Anserinae Tadorninae Anatinae Oxyurinae Incertae sedis Putative or disputed prehistoric anatids are: The Middle Oligocene Limicorallus (from Chelkar-Teniz ( Kazakhstan )
1012-479: The back of the body (more so in the more aquatic species), and have a leathery feel with a scaly texture. Combined with their body shape, this can make some species awkward on land, but they are stronger walkers than other marine and water birds such as grebes or petrels . They typically have webbed feet , though a few species such as the Nene have secondarily lost their webbing. The bills are made of soft keratin with
1056-453: The deserts of southern Africa , needing to keep its eggs cool during the heat of the day, stands over them drooping its wings to shade them. The humidity is also critical, because if the air is too dry the egg will lose too much water to the atmosphere, which can make hatching difficult or impossible. As incubation proceeds, an egg will normally become lighter, and the air space within the egg will normally become larger, owing to evaporation from
1100-431: The egg, after the egg's formation and ovipositional release. Egg incubation is done under favorable environmental conditions, possibly by brooding and hatching the egg. Multiple and various factors are vital to the incubation of various species of animal. In many species of reptile for example, no fixed temperature is necessary, but the actual temperature determines the sex ratio of the offspring . In birds in contrast,
1144-403: The egg. During incubation, the inner layers of the shell are dissolved by their acidic environment and the calcium carbonate that had been part of the shell is incorporated into the skeleton of the foetus. Experiments with great tits show that females compensate for the potential effects of differential heating by moving the eggs homogeneously within the clutch. In the species that incubate,
1188-418: The eggs are inserted. Other neotropical frogs in the family Hemiphractidae also have pouches in which the eggs develop, in some species directly into juvenile frogs and in others into tadpoles that are later deposited in small water bodies to continue their development. The male Darwin's frog carries the eggs around in his mouth until metamorphosis , and the female stomach-brooding frog of Australia swallows
1232-540: The family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them were not named) in some but not in all his orders of "insects" (which then included all arthropods ). In nineteenth-century works such as the Prodromus of Augustin Pyramus de Candolle and
1276-469: The female curls around them. The incubation period is divided into three phases. In the first phase, the embryo has no functional organs and relies on the yolk sac for sustenance. The yolk is absorbed by the developing young. During the second phase, the digits develop. In the last phase, the egg tooth appears. Methods of incubation vary widely among the many different kinds of reptiles. Various species of sea turtles bury their eggs on beaches under
1320-408: The female's first clutch, but if she lays a second, she incubates it herself. In hoatzins , some birds (mostly males) help their parents incubate later broods. The incubation period, the time from the start of uninterrupted incubation to the emergence of the young, varies from 11 days (some small passerines and the black-billed and yellow-billed cuckoos ) to 85 days (the wandering albatross and
1364-472: The ground. Fish generally do not incubate their eggs. However, some species mouthbrood their eggs, not eating until they hatch. Some amphibians brood their eggs. The female salamander Ensatina ( Ensatina eschscholtzii ) curls around the clutch of eggs and massages individual eggs with her pulsating throat. Some aquatic frogs such as the Surinam toad ( Pipa pipa ) have pouches in their skin into which
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1408-405: The last egg of the clutch, causing the young to hatch simultaneously. Incubation periods for birds: The only living mammals that lay eggs are echidnas and platypuses . In the latter, the eggs develop in utero for about 28 days, with only about 10 days of external incubation (in contrast to a chicken egg, which spends about one day in tract and 21 days externally). After laying her eggs,
1452-536: The males being more brightly coloured than the females (although the situation is reversed in species such as the paradise shelduck ). The swans, geese, and whistling-ducks lack sexually dimorphic plumage. Anatids are vocal birds, producing a range of quacks, honks, squeaks, and trumpeting sounds, depending on species; the female often has a deeper voice than the male. Anatids are generally herbivorous as adults, feeding on various water-plants, although some species also eat fish, molluscs, or aquatic arthropods. One group,
1496-440: The many species within the Anatidae; see discussion in the next section. The systematics of the Anatidae are in a state of flux. Previously divided into six subfamilies, a study of anatomical characters by Livezey suggests the Anatidae are better treated in nine subfamilies. This classification was popular in the late 1980s to 1990s. But mtDNA sequence analyses indicate, for example, the dabbling and diving ducks do not belong in
1540-429: The mound and ambient temperature. Even in other birds, ambient temperatures can lead to variation in incubation period. Normally the egg is incubated outside the body. However, in one recorded case, the egg incubation occurred entirely within a chicken. The chick hatched inside and emerged from its mother without the shell, leading to internal wounds that killed the mother hen. Embryo development remains suspended until
1584-412: The non-avian dinosaurs . The long period of evolution and shifts from one kind of waterbird lifestyle to another have obscured many plesiomorphies , while apparent apomorphies are quite often the result of parallel evolution , for example the "non-diving duck" type displayed by such unrelated genera as Dendrocygna , Amazonetta , and Cairina . For the fossil record, see below. Alternatively,
1628-486: The onset of incubation. The freshly laid eggs of domestic fowl, ostrich, and several other species can be stored for about two weeks when maintained under 5 °C. Extended periods of suspension have been observed in some marine birds. Some species begin incubation with the first egg, causing the young to hatch at different times; others begin after laying the second egg, so that the third chick will be smaller and more vulnerable to food shortages. Some start to incubate after
1672-455: The same subfamily. While shortcomings certainly occur in Livezey's analysis, mtDNA is an unreliable source for phylogenetic information in many waterfowl (especially dabbling ducks) due to their ability to produce fertile hybrids , in rare cases possibly even beyond the level of genus (see for example the " Barbary duck "). Because the sample size of many molecular studies available to date
1716-575: The seventy-six groups of plants he recognised in his tables families ( familiae ). The concept of rank at that time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera , which is far from how the term is used today. In his work Philosophia Botanica published in 1751, Carl Linnaeus employed the term familia to categorize significant plant groups such as trees , herbs , ferns , palms , and so on. Notably, he restricted
1760-482: The sex of offspring is genetically determined, but in many species a constant and particular temperature is necessary for successful incubation. Especially in poultry , the act of sitting on eggs to incubate them is called brooding. The action or behavioral tendency to sit on a clutch of eggs is also called broodiness , and most egg -laying breeds of poultry have had this behavior selectively bred out of them to increase production. A wide range of incubation habits
1804-549: The use of this term solely within the book's morphological section, where he delved into discussions regarding the vegetative and generative aspects of plants. Subsequently, in French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis ). In zoology ,
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1848-463: The water only. They construct simple nests from whatever material is close at hand, often lining them with a layer of down plucked from the mother's breast. In most species, only the female incubates the eggs. The young are precocial , and are able to feed themselves from birth. One aberrant species, the black-headed duck , is an obligate brood parasite , laying its eggs in the nests of gulls and coots . While this species never raises its own young,
1892-531: The work is divided differently between the sexes. Possibly the most common pattern is that the female does all the incubation, as in the Atlantic canary and the Indian robin , or most of it, as is typical of falcons . In some species, such as the whooping crane , the male and the female take turns incubating the egg. In others, such as the cassowaries , only the male incubates. The male mountain plover incubates
1936-495: Was sometimes considered an anserine. It is now recognized as a primitive cormorant . The middle Eocene Eonessa was formerly thought to belong to Anatidae, however reexamination of the holotype in 1978 resulted in the genus being placed as Aves incertae sedis . Family (biology) Family ( Latin : familia , pl. : familiae ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy . It
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