80-593: The Andean lapwing ( Vanellus resplendens ) is a species of bird in family Charadriidae , the plovers and their relatives. It is found in Argentina , Bolivia , Chile , Colombia , Ecuador , and Peru . The Andean lapwing was originally described as Charadrius resplendens and has sometimes been placed in genus Ptiloscelys . It is monotypic . The Andean lapwing is about 33 cm (13 in) long and weighs 193 to 230 g (6.8 to 8.1 oz). The sexes are alike and have no seasonal changes in plumage. Adults have
160-519: A leopard seal ) has difficulty distinguishing between a white penguin belly and the reflective water surface. The dark plumage on their backs camouflages them from above. Gentoo penguins are the fastest underwater birds in the world. They are capable of reaching speeds up to 36 km (about 22 miles) per hour while searching for food or escaping from predators. They are also able to dive to depths of 170–200 meters (about 560–660 feet). The small penguins do not usually dive deep; they catch their prey near
240-801: A better sense of smell. A third stage of bird evolution starting with Ornithothoraces (the "bird-chested" avialans) can be associated with the refining of aerodynamics and flight capabilities, and the loss or co-ossification of several skeletal features. Particularly significant are the development of an enlarged, keeled sternum and the alula , and the loss of grasping hands. † Anchiornis † Archaeopteryx † Xiaotingia † Rahonavis † Jeholornis † Jixiangornis † Balaur † Zhongjianornis † Sapeornis † Confuciusornithiformes † Protopteryx † Pengornis Ornithothoraces † Enantiornithes Penguin For prehistoric genera, see List of penguins#Fossil genera Penguins are
320-454: A breeding season, though the rate the same pair recouples varies drastically. Most penguins lay two eggs in a clutch, although the two largest species, the emperor and the king penguins , lay only one. With the exception of the emperor penguin, where the male does it all, all penguins share the incubation duties. These incubation shifts can last days and even weeks as one member of the pair feeds at sea. Penguins generally only lay one brood;
400-535: A continuous circumpolar flow only around 30 mya, on the one hand forcing the Antarctic cooling, and on the other facilitating the eastward expansion of Spheniscus to South America and eventually beyond. Despite this, there is no fossil evidence to support the idea of crown radiation from the Antarctic continent in the Paleogene, although DNA study favors such a radiation. Later, an interspersed period of slight warming
480-444: A creamy gray head and neck with a dark brownish gray patch around the eye. Their upperparts are bronzy green with a purple patch on the wing coverts . Their breast is dark gray and their belly white. Their bill is pinkish orange with a black tip, their eye is reddish, and their legs are also reddish. Juveniles have a brownish head and neck, buff mottling on the breast, and pale buff fringes on the upperparts feathers. The Andean lapwing
560-473: A definition similar to "all theropods closer to birds than to Deinonychus ", with Troodon being sometimes added as a second external specifier in case it is closer to birds than to Deinonychus . Avialae is also occasionally defined as an apomorphy-based clade (that is, one based on physical characteristics). Jacques Gauthier , who named Avialae in 1986, re-defined it in 2001 as all dinosaurs that possessed feathered wings used in flapping flight , and
640-442: A group called Paraves . Some basal members of Deinonychosauria, such as Microraptor , have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small. This evidence raises the possibility that the ancestor of all paravians may have been arboreal , have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, studies suggest that
720-796: A group of aquatic flightless birds from the family Spheniscidae ( / s f ɪ ˈ n ɪ s ɪ d iː , - d aɪ / ) of the order Sphenisciformes ( / s f ɪ ˈ n ɪ s ə f ɔːr m iː z / ). They live almost exclusively in the Southern Hemisphere : only one species , the Galápagos penguin , is found north of the Equator . Highly adapted for life in the ocean water, penguins have countershaded dark and white plumage and flippers for swimming. Most penguins feed on krill , fish , squid and other forms of sea life which they catch with their bills and swallow whole while swimming. A penguin has
800-458: A group of penguins on land is a waddle , and a group of penguins in the water is a raft . Since 1871, the Latin word Pinguinus has been used in scientific classification to name the genus of the great auk ( Pinguinus impennis , meaning "plump or fat without flight feathers "), which became extinct in the mid-19th century. As confirmed by a 2004 genetic study, the genus Pinguinus belongs in
880-424: A maritime context, pen blaen means 'front end or part, bow (of a ship), prow'. An alternative etymology links the word to Latin pinguis , which means 'fat' or 'oil'. Support for this etymology can be found in the alternative Germanic word for penguin, fettgans or 'fat-goose', and the related Dutch word vetgans . Adult male penguins are sometimes called cocks , females sometimes called hens ;
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#1733116212504960-473: A mostly Subantarctic distribution centred on South America ; some, however, range quite far northwards. They all lack carotenoid colouration and the former genus has a conspicuous banded head pattern; they are unique among living penguins by nesting in burrows. This group probably radiated eastwards with the Antarctic Circumpolar Current out of the ancestral range of modern penguins throughout
1040-520: A region around 2,000 km south of the equator 35 mya , during the Late Eocene , a climate decidedly warmer than today. The word penguin first appears in literature at the end of the 16th century as a synonym for the great auk . When European explorers discovered what are today known as penguins in the Southern Hemisphere, they noticed their similar appearance to the great auk of
1120-406: A sister group, the order Crocodilia , contain the only living representatives of the reptile clade Archosauria . During the late 1990s, Aves was most commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica . However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, and
1200-408: A spiny tongue and powerful jaws to grip slippery prey. They spend about half of their lives on land and the other half in the sea. The largest living species is the emperor penguin ( Aptenodytes forsteri ): on average, adults are about 1.1 m (3 ft 7 in) tall and weigh 35 kg (77 lb). The smallest penguin species is the little blue penguin ( Eudyptula minor ), also known as
1280-567: A staccato 'cwi-cwi-cwi...' or more mellow and melodic 'dididi---celeec-celeec-celeec-ce...'." It also makes "a soft querulous 'cow' note...or a low, tremulous 'kwiwiwiwirrr'." The IUCN has assessed the Andean lapwing as being of Least Concern. It has a large range, and its estimated population of under 6700 mature individuals is believed to be stable. No immediate threats have been identified. "Occupation of bleak high-altitude habitats with relatively low densities of humans suggests [that the] species
1360-717: A time, sometimes for years, and rarely for life. Other species have breeding systems that are polygynous (one male with many females) or, rarely, polyandrous (one female with many males). Birds produce offspring by laying eggs which are fertilised through sexual reproduction . They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs, meat, and feathers. Songbirds , parrots, and other species are popular as pets. Guano (bird excrement)
1440-489: Is found as high as 5,000 m (16,000 ft) in Chile and as low as 1,500 m (4,900 ft) in the southern parts of its range. It occasionally reaches the coast during the austral winter. The Andean lapwing is essentially resident in most of its range but moves to lower elevations during the austral winter. Nothing is known about the Andean lapwing's foraging techniques or its diet. The Andean lapwing's breeding season
1520-465: Is found in the Andes from southwestern Colombia south through Ecuador, Peru, and Bolivia into northern Chile and northwestern Argentina. It inhabits a variety of open landscapes including páramo and puna , shore meadows, and open parts of marshes. It is usually found near lakes or rivers but shuns saline waters. In general it ranges between 2,700 and 4,600 m (8,900 and 15,100 ft) of elevation but
1600-429: Is harvested for use as a fertiliser. Birds figure throughout human culture. About 120 to 130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds
1680-406: Is mostly between October and December though occasionally it may extend to February. One nest was a depression in the ground lined with plant material including lichens. The clutch size is three or four. The incubation period and time to fledging are not known. [REDACTED] Like most lapwings, the Andean is noisy. "[U]sually heard are a sharp 'wik' in alarm, a harsh 'criee-criee-cri' call,
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#17331162125041760-460: Is much greater than in air). The emperor penguin has a maximum feather density of about nine feathers per square centimeter which is actually much lower than other birds that live in Antarctic environments. However, they have been identified as having at least four different types of feather: in addition to the traditional feather, the emperor has afterfeathers , plumules , and filoplumes . The afterfeathers are downy plumes that attach directly to
1840-503: Is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor. Over 40% of key traits found in modern birds evolved during the 60 million year transition from the earliest bird-line archosaurs to the first maniraptoromorphs , i.e. the first dinosaurs closer to living birds than to Tyrannosaurus rex . The loss of osteoderms otherwise common in archosaurs and acquisition of primitive feathers might have occurred early during this phase. After
1920-451: Is or includes the paleeudyptines as recognized today – occurred on most Antarctic and Subantarctic coasts. Size plasticity was significant at this initial stage of radiation : on Seymour Island , Antarctica, for example, around 10 known species of penguins ranging in size from medium to large apparently coexisted some 35 mya during the Priabonian (Late Eocene). It is not known whether
2000-442: Is probably secure at present." Bird Birds are a group of warm-blooded vertebrates constituting the class Aves ( Latin: [ˈaveːs] ), characterised by feathers , toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart , and a strong yet lightweight skeleton . Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to
2080-482: Is sometimes called " higher waterbirds " to distinguish them from the more ancient waterfowl . This group contains such birds as storks , rails , and the seabirds , with the possible exception of the Charadriiformes . Inside this group, penguin relationships are far less clear. Depending on the analysis and dataset, a close relationship to Ciconiiformes or to Procellariiformes has been suggested. Some think
2160-516: Is synonymous to Avifilopluma. † Scansoriopterygidae † Eosinopteryx † Jinfengopteryx † Aurornis † Dromaeosauridae † Troodontidae Avialae Based on fossil and biological evidence, most scientists accept that birds are a specialised subgroup of theropod dinosaurs and, more specifically, members of Maniraptora , a group of theropods which includes dromaeosaurids and oviraptorosaurs , among others. As scientists have discovered more theropods closely related to birds,
2240-530: Is used by many scientists including adherents to the PhyloCode . Gauthier defined Aves to include only the crown group of the set of modern birds. This was done by excluding most groups known only from fossils , and assigning them, instead, to the broader group Avialae, on the principle that a clade based on extant species should be limited to those extant species and their closest extinct relatives. Gauthier and de Queiroz identified four different definitions for
2320-404: Is used by parents and chicks to locate one another in crowded colonies . Their eyes are adapted for underwater vision and are their primary means of locating prey and avoiding predators; in air it has been suggested that they are nearsighted , although research has not supported this hypothesis. Penguins have a thick layer of insulating feathers that keeps them warm in water (heat loss in water
2400-643: Is well-researched, many prehistoric forms are not fully described . Some seminal articles about the evolutionary history of penguins have been published since 2005. The basal penguins lived around the time of the Cretaceous–Paleogene extinction event in the general area of southern New Zealand and Byrd Land , Antarctica. Due to plate tectonics , these areas were at that time less than 1,500 kilometres (930 mi) apart rather than 4,000 kilometres (2,500 mi). The most recent common ancestor of penguins and Procellariiformes can be roughly dated to
2480-735: The Oxford English Dictionary , the American Heritage Dictionary , the Century Dictionary and Merriam-Webster , on the basis that the name was originally applied to the great auk, either because it was found on White Head Island ( Welsh : Pen Gwyn ) in Newfoundland, or because it had white circles around its eyes (though the head was black). However, the Welsh word pen can also be used to mean 'front' and, in
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2560-463: The Antarctic Peninsula and Patagonia have not yielded Paleogene fossils of the subfamily. Also, the earliest spheniscine lineages are those with the most southern distribution. The genus Aptenodytes appears to be the basalmost divergence among living penguins. They have bright yellow-orange neck, breast, and bill patches; incubate by placing their eggs on their feet, and when they hatch
2640-635: The Campanian – Maastrichtian boundary, around 70–68 mya. The oldest known fossil penguin species is Waimanu manneringi , which lived 62 mya in New Zealand. While they were not as well-adapted to aquatic life as modern penguins, Waimanu were flightless, with short wings adapted for deep diving. They swam on the surface using mainly their feet, but the wings were – as opposed to most other diving birds (both living and extinct) – already adapting to underwater locomotion. Perudyptes from northern Peru
2720-610: The Chattian (Late Oligocene), starting approximately 28 mya. While the two genera separated during this time, the present-day diversity is the result of a Pliocene radiation, taking place some 4–2 mya. The Megadyptes – Eudyptes clade occurs at similar latitudes (though not as far north as the Galápagos penguin ), has its highest diversity in the New Zealand region, and represents a westward dispersal. They are characterized by hairy yellow ornamental head feathers; their bills are at least partly red. These two genera diverged apparently in
2800-605: The Northern Hemisphere and named them after this bird, although they are not closely related. The etymology of the word penguin is still debated. The English word is not apparently of French , Breton or Spanish origin (the latter two are attributed to the French word pingouin ), but first appears in English or Dutch. Some dictionaries suggest a derivation from Welsh pen , 'head' and gwyn , 'white', including
2880-660: The Tiaojishan Formation of China, which has been dated to the late Jurassic period ( Oxfordian stage), about 160 million years ago. The avialan species from this time period include Anchiornis huxleyi , Xiaotingia zhengi , and Aurornis xui . The well-known probable early avialan, Archaeopteryx , dates from slightly later Jurassic rocks (about 155 million years old) from Germany . Many of these early avialans shared unusual anatomical features that may be ancestral to modern birds but were later lost during bird evolution. These features include enlarged claws on
2960-422: The loss of flight in some birds , including ratites , penguins , and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds , have further evolved for swimming. The study of birds is called ornithology . Birds are feathered theropod dinosaurs and constitute
3040-561: The only known living dinosaurs . Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians . Birds are descendants of the primitive avialans (whose members include Archaeopteryx ) which first appeared during the Late Jurassic . According to recent estimates, modern birds ( Neornithes ) evolved in the Late Cretaceous and diversified dramatically around
3120-489: The phylogenetic taxon Spheniscidae to what here is referred to as Spheniscinae. Furthermore, they restrict the phylogenetic taxon Sphenisciformes to flightless taxa, and establish the phylogenetic taxon Pansphenisciformes as equivalent to the Linnean taxon Sphenisciformes, i.e., including any flying basal "proto-penguins" to be discovered eventually. Given that neither the relationships of the penguin subfamilies to each other nor
3200-573: The "heterothermic loophole" that penguins utilize in order to survive in Antarctica. All extant penguins, even those that live in warmer climates, have a counter-current heat exchanger called the humeral plexus. The flippers of penguins have at least three branches of the axillary artery, which allows cold blood to be heated by blood that has already been warmed and limits heat loss from the flippers. This system allows penguins to efficiently use their body heat and explains why such small animals can survive in
3280-440: The 2.8 m (9 ft 2 in) common ostrich . There are over 11,000 living species and they are split into 44 orders . More than half are passerine or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds . Wings, which are modified forelimbs , gave birds the ability to fly, although further evolution has led to
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3360-514: The Middle Miocene ( Langhian , roughly 15–14 mya), although the living species of Eudyptes are the product of a later radiation, stretching from about the late Tortonian (Late Miocene, 8 mya) to the end of the Pliocene. The geographical and temporal pattern of spheniscine evolution corresponds closely to two episodes of global cooling documented in the paleoclimatic record . The emergence of
3440-527: The Spheniscinae lies probably in the latest Paleogene and, geographically, it must have been much the same as the general area in which the order evolved: the oceans between the Australia-New Zealand region and the Antarctic. Presumably diverging from other penguins around 40 mya, it seems that the Spheniscinae were for quite some time limited to their ancestral area, as the well-researched deposits of
3520-665: The Spheniscinae, as Aptenodytes ' autapomorphies are, in most cases, fairly pronounced adaptations related to that genus' extreme habitat conditions. As the former genus, Pygoscelis seems to have diverged during the Bartonian, but the range expansion and radiation that led to the present-day diversity probably did not occur until much later; around the Burdigalian stage of the Early Miocene , roughly 20–15 mya. The genera Spheniscus and Eudyptula contain species with
3600-530: The Subantarctic lineage at the end of the Bartonian corresponds with the onset of the slow period of cooling that eventually led to the ice ages some 35 million years later. With habitat on the Antarctic coasts declining, by the Priabonian more hospitable conditions for most penguins existed in the Subantarctic regions rather than in Antarctica itself. Notably, the cold Antarctic Circumpolar Current also started as
3680-533: The air. In the water, however, penguins are astonishingly agile. Penguins' swimming looks very similar to birds' flight in the air. Within the smooth plumage a layer of air is preserved, ensuring buoyancy. The air layer also helps insulate the birds in cold waters. On land, penguins use their tails and wings to maintain balance for their upright stance. All penguins are countershaded for camouflage – that is, they have black backs and wings with white fronts. A predator looking up from below (such as an orca or
3760-428: The appearance of Maniraptoromorpha, the next 40 million years marked a continuous reduction of body size and the accumulation of neotenic (juvenile-like) characteristics. Hypercarnivory became increasingly less common while braincases enlarged and forelimbs became longer. The integument evolved into complex, pennaceous feathers . The oldest known paravian (and probably the earliest avialan) fossils come from
3840-509: The birds that descended from them. Despite being currently one of the most widely used, the crown-group definition of Aves has been criticised by some researchers. Lee and Spencer (1997) argued that, contrary to what Gauthier defended, this definition would not increase the stability of the clade and the exact content of Aves will always be uncertain because any defined clade (either crown or not) will have few synapomorphies distinguishing it from its closest relatives. Their alternative definition
3920-421: The chicks are almost naked. This genus has a distribution centred on the Antarctic coasts and barely extends to some Subantarctic islands today. Pygoscelis contains species with a fairly simple black-and-white head pattern; their distribution is intermediate, centred on Antarctic coasts but extending somewhat northwards from there. In external morphology , these apparently still resemble the common ancestor of
4000-665: The earliest members of Aves, is removed from this group, becoming a non-avian dinosaur instead. These proposals have been adopted by many researchers in the field of palaeontology and bird evolution , though the exact definitions applied have been inconsistent. Avialae, initially proposed to replace the traditional fossil content of Aves, is often used synonymously with the vernacular term "bird" by these researchers. † Coelurus † Ornitholestes † Ornithomimosauria † Alvarezsauridae † Oviraptorosauria Paraves Most researchers define Avialae as branch-based clade, though definitions vary. Many authors have used
4080-517: The emergence of another morphotype in the same area, the similarly sized but more gracile Palaeospheniscinae , as well as the radiation that gave rise to the current biodiversity of penguins. Modern penguins constitute two undisputed clades and another two more basal genera with more ambiguous relationships. To help resolve the evolution of this order , 19 high-coverage genomes that, together with two previously published genomes, encompass all extant penguin species have been sequenced. The origin of
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#17331162125044160-581: The end of the Paleogene , around 25 mya. Their decline and disappearance coincided with the spread of the Squalodontidae and other primitive, fish-eating toothed whales , which competed with them for food and were ultimately more successful. A new lineage, the Paraptenodytes , which includes smaller and stout-legged forms, had already arisen in southernmost South America by that time. The early Neogene saw
4240-402: The exception is the little penguin, which can raise two or three broods in a season. Penguin eggs are smaller than any other bird species when compared proportionally to the weight of the parent birds; at 52 g (2 oz), the little penguin egg is 4.7% of its mothers' weight, and the 450 g (1 lb) emperor penguin egg is 2.3%. The relatively thick shell forms between 10 and 16% of
4320-475: The extreme cold of the Antarctic winter, the females are at sea fishing for food, leaving the males to brave the weather by themselves. They often huddle together to keep warm and rotate positions to make sure that each penguin gets a turn in the centre of the heat pack. Calculations of the heat loss and retention ability of marine endotherms suggest that most extant penguins are too small to survive in such cold environments. In 2007, Thomas and Fordyce wrote about
4400-463: The extreme cold. They can drink salt water because their supraorbital gland filters excess salt from the bloodstream. The salt is excreted in a concentrated fluid from the nasal passages. The great auk of the Northern Hemisphere, now extinct, was superficially similar to penguins, and the word penguin was originally used for that bird centuries ago. They are only distantly related to
4480-442: The fairy penguin, which stands around 30–33 cm (12–13 in) tall and weighs 1.2–1.3 kg (2.6–2.9 lb). Today, larger penguins generally inhabit colder regions, and smaller penguins inhabit regions with temperate or tropical climates . Some prehistoric penguin species were enormous: as tall or heavy as an adult human. There was a great diversity of species in subantarctic regions, and at least one giant species in
4560-400: The family of the auks (Alcidae), within the order of the Charadriiformes . The birds currently known as penguins were discovered later and were so named by sailors because of their physical resemblance to the great auk. Despite this resemblance, however, they are not auks, and are not closely related to the great auk. They do not belong in the genus Pinguinus , and are not classified in
4640-451: The first avialans were omnivores . The Late Jurassic Archaeopteryx is well known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to display both clearly traditional reptilian characteristics—teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It
4720-414: The main feathers and were once believed to account for the bird's ability to conserve heat when under water; the plumules are small down feathers that attach directly to the skin, and are much more dense in penguins than other birds; lastly the filoplumes are small (less than 1 cm long) naked shafts that end in a splay of fibers— filoplumes were believed to give flying birds a sense of where their plumage
4800-607: The most part breed in large colonies, the exceptions being the yellow-eyed and Fiordland species; these colonies may range in size from as few as 100 pairs for gentoo penguins to several hundred thousand in the case of king, macaroni and chinstrap penguins. Living in colonies results in a high level of social interaction between birds, which has led to a large repertoire of visual as well as vocal displays in all penguin species. Agonistic displays are those intended to confront or drive off, or alternately appease and avoid conflict with, other individuals. Penguins form monogamous pairs for
4880-402: The outermost half) can be seen in the evolution of maniraptoromorphs, and this process culminated in the appearance of the pygostyle , an ossification of fused tail vertebrae. In the late Cretaceous, about 100 million years ago, the ancestors of all modern birds evolved a more open pelvis, allowing them to lay larger eggs compared to body size. Around 95 million years ago, they evolved
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#17331162125044960-637: The palaeeudyptines constitute a monophyletic lineage, or whether gigantism was evolved independently in a restricted Palaeeudyptinae and the Anthropornithinae – whether they were considered valid, or whether there was a wide size range present in the Palaeeudyptinae as delimited (i.e., including Anthropornis nordenskjoeldi ). The oldest well-described giant penguin, the 5-foot (1.5 m)-tall Icadyptes salasi , existed as far north as northern Peru about 36 mya. Gigantic penguins had disappeared by
5040-466: The penguin-like plotopterids (usually considered relatives of cormorants and anhingas ) may actually be a sister group of the penguins and those penguins may have ultimately shared a common ancestor with the Pelecaniformes and consequently would have to be included in that order, or that the plotopterids were not as close to other pelecaniforms as generally assumed, which would necessitate splitting
5120-408: The penguins, but are an example of convergent evolution . Around one in 50,000 penguins (of most species) are born with brown rather than black plumage. These are called isabelline penguins. Isabellinism is different from albinism. Isabelline penguins tend to live shorter lives than normal penguins, as they are not well-camouflaged against the deep and are often passed over as mates. Penguins for
5200-594: The penguins, puffins have a white chest, black back and short stubby wings providing excellent swimming ability in icy water. But, unlike penguins, puffins can fly, as flightless birds would not survive alongside land-based predators such as polar bears and foxes; there are no such predators in the Antarctic. Their similarities indicate that similar environments, although at great distances, can result in similar evolutionary developments, i.e. convergent evolution . Penguins are superbly adapted to aquatic life. Their wings have evolved to become flippers, useless for flight in
5280-400: The placement of the penguins in the avian phylogeny is presently resolved, this is confusing, so the established Linnean system is followed here. The number of penguin species is typically listed as between seventeen and nineteen. The International Ornithologists' Union recognizes six genera and eighteen species: Although the evolutionary and biogeographic history of Sphenisciformes
5360-528: The previously clear distinction between non-birds and birds has become blurred. By the 2000s, discoveries in the Liaoning Province of northeast China, which demonstrated many small theropod feathered dinosaurs , contributed to this ambiguity. The consensus view in contemporary palaeontology is that the flying theropods, or avialans , are the closest relatives of the deinonychosaurs , which include dromaeosaurids and troodontids . Together, these form
5440-452: The same biological name "Aves", which is a problem. The authors proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below. They assigned other names to the other groups. Lizards & snakes Turtles Crocodiles Birds Under the fourth definition Archaeopteryx , traditionally considered one of
5520-514: The same family and order as the great auk. They were classified in 1831 by Charles Lucien Bonaparte in several distinct genera within the family Spheniscidae and order Sphenisciformes . The family name of Spheniscidae was given by Charles Lucien Bonaparte from the genus Spheniscus , the name of that genus comes from the Greek word σφήν sphēn " wedge " used for the shape of an African penguin 's swimming flippers. Some recent sources apply
5600-545: The second toe which may have been held clear of the ground in life, and long feathers or "hind wings" covering the hind limbs and feet, which may have been used in aerial maneuvering. Avialans diversified into a wide variety of forms during the Cretaceous period. Many groups retained primitive characteristics , such as clawed wings and teeth, though the latter were lost independently in a number of avialan groups, including modern birds (Aves). Increasingly stiff tails (especially
5680-537: The strong adaptive autapomorphies of the Sphenisciformes; a sometimes perceived fairly close relationship between penguins and grebes is almost certainly an error based on both groups' strong diving adaptations, which are homoplasies . On the other hand, different DNA sequence datasets do not agree in detail with each other either. What seems clear is that penguins belong to a clade of Neoaves (living birds except for paleognaths and fowl ) that comprises what
5760-641: The surface in dives that normally last only one or two minutes. Larger penguins can dive deep in case of need. Emperor penguins are the world's deepest-diving birds. They can dive to depths of approximately 550 meters (1,800 feet) while searching for food. Penguins either waddle on their feet or slide on their bellies across the snow while using their feet to propel and steer themselves, a movement called "tobogganing", which conserves energy while moving quickly. They also jump with both feet together if they want to move more quickly or cross steep or rocky terrain. Penguins have an average sense of hearing for birds; this
5840-538: The time of the Cretaceous–Paleogene extinction event 66 million years ago, which killed off the pterosaurs and all non- ornithuran dinosaurs. Many social species preserve knowledge across generations ( culture ). Birds are social, communicating with visual signals, calls, and songs , and participating in such behaviour as cooperative breeding and hunting, flocking , and mobbing of predators. The vast majority of bird species are socially (but not necessarily sexually) monogamous , usually for one breeding season at
5920-545: The traditional Pelecaniformes into three. A 2014 analysis of whole genomes of 48 representative bird species has concluded that penguins are the sister group of Procellariiformes, from which they diverged about 60 million years ago (95% CI, 56.8–62.7). The distantly related Puffins , which live in the North Pacific and North Atlantic, developed similar characteristics to survive in the Arctic and sub-Arctic environments. Like
6000-491: The weight of a penguin egg, presumably to reduce the effects of dehydration and to minimize the risk of breakage in an adverse nesting environment. The yolk, too, is large and comprises 22–31% of the egg. Some yolk often remains when a chick is born, and is thought to help sustain the chick if the parents are delayed in returning with food. When emperor penguin mothers lose a chick, they sometimes attempt to "steal" another mother's chick, usually unsuccessfully as other females in
6080-417: Was and whether or not it needed preening, so their presence in penguins may seem inconsistent, but penguins also preen extensively. The emperor penguin has the largest body mass of all penguins, which further reduces relative surface area and heat loss. They also are able to control blood flow to their extremities, reducing the amount of blood that gets cold, but still keeping the extremities from freezing. In
6160-627: Was dated to 42 mya. An unnamed fossil from Argentina proves that, by the Bartonian (Middle Eocene), some 39–38 mya, primitive penguins had spread to South America and were in the process of expanding into Atlantic waters. During the Late Eocene and the Early Oligocene (40–30 mya), some lineages of gigantic penguins existed. Nordenskjoeld's giant penguin was the tallest, growing nearly 1.80 meters (5.9 feet) tall. The New Zealand giant penguin
6240-461: Was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae . Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use. Birds are categorised as the biological class Aves in Linnaean taxonomy . Phylogenetic taxonomy places Aves in the clade Theropoda as an infraclass or a subclass, more recently a subclass. Aves and
6320-747: Was ended by the Middle Miocene Climate Transition , a sharp drop in global average temperature from 14 to 12 mya, and similar abrupt cooling events followed at 8 mya and 4 mya; by the end of the Tortonian, the Antarctic ice sheet was already much like today in volume and extent. The emergence of most of today's Subantarctic penguin species almost certainly was caused by this sequence of Neogene climate shifts. Penguin ancestry beyond Waimanu remains unknown and not well-resolved by molecular or morphological analyses. The latter tend to be confounded by
6400-601: Was probably the heaviest, weighing 80 kilograms (180 lb) or more. Both were found on New Zealand, the former also in the Antarctic farther eastwards. Traditionally, most extinct species of penguins, giant or small, had been placed in the paraphyletic subfamily called Palaeeudyptinae . More recently, with new taxa being discovered and placed in the phylogeny if possible, it is becoming accepted that there were at least two major extinct lineages. One or two closely related ones occurred in Patagonia , and at least one other—which
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