83-400: The banded penguins are penguins that belong to the genus Spheniscus . There are four living species, all with similar banded plumage-patterns. They are sometimes also known as "jack-ass penguins" due to their loud locator-calls sounding similar to a donkey braying. Common traits include a band of black that runs around their bodies bordering their black dorsal coloring, black beaks with
166-519: 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
249-454: 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;
332-480: A broad neocortex region of the brain, fur or hair , and three middle ear bones . These characteristics distinguish them from reptiles and birds , from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,400 extant species of mammals have been described and divided into 27 orders . The largest orders of mammals, by number of species , are
415-545: 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
498-401: A different source and filter to produce vocalizations. They use a structure called the syrinx as their source of vibrations and their trachea acts as the filter. The source-filter theory has become increasingly popular to study birds, such as various species of banded penguins. This theory can be used to investigate how acoustic variation and individuality within a set of closely related species
581-462: 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
664-424: 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 ;
747-485: 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
830-535: 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
913-450: A sequence of distinct acoustic syllables that combine to form a complete phrase and are often displayed during their breeding season. Despite the close relatedness of banded penguin species, the ecstatic display calls of African, Humboldt and Magellanic penguins are distinctly recognizable, even to human listeners. Typically, females respond more strongly to ecstatic display calls from their mates than from other conspecifics. Furthermore, there
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#1732780111253996-403: A small vertical white band, distinct spots on their bellies, and a small patch of unfeathered or thinly feathered skin around their eyes and underdeveloped fluff sack that can be either white or pink. All members of this genus lay eggs and raise their young in nests situated in burrows or in natural depressions in the earth. Banded penguins belong to the genus Spheniscus , which was introduced by
1079-512: A social group, to identify ones self and to maintain contact with a mate. Vocal individuality has evolved in banded penguins due to their large social group sizes. Contact calls are frequently used by banded penguins to form large flocks when foraging at sea. It is easy to become separated while diving for food, therefore these penguins use contact calls to stay in contact with each other when they are out of sight. A contact call can relay an excess of information about an individual penguin, including
1162-408: 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
1245-406: Is a framework used for studying the communication of mammalian animals through vocalizations. According to this theory, acoustic calls are produced by a source and then must be filtered to remove certain frequencies or leave others unchanged, which produces vocal individuality. In mammals, the source is the vibrations in the larynx and the filter is the super laryngeal vocal tract. However, birds use
1328-453: Is attributed to distinct morphological differences in their vocal organs. The equivalence of the source-filter theory in humans is the source-filter model of speech production . Penguin For prehistoric genera, see List of penguins#Fossil genera Penguins are a group of aquatic flightless birds from the family Spheniscidae ( / s f ɪ ˈ n ɪ s ɪ d iː , - d aɪ / ) of
1411-511: Is evidence to suggest that ecstatic display songs may convey vocal individuality through the type of syllables the song produces. This vocal individuality can convey information such as body size and weight, since heavier penguins typically emit longer and lower-pitched vocalizations. Mutual display songs are similar to ecstatic display songs in that they are also complex sequences of acoustic syllables. However, mutual display songs are performed by mates at their nesting site. The source-filter theory
1494-460: 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
1577-537: Is now placed in a monotypic genus Inguza . Scientists believe that the genus Spheniscus originated in South America , even though the oldest fossils assigned to the taxon are from Antarctica . The oldest Spheniscus fossils are also the oldest penguin fossils from Antarctica. African, Humboldt, and Magellanic penguins all live in temperate climates . The African penguin lives in South Africa ,
1660-457: 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
1743-572: Is primarily driven by human poaching and habitat destruction , primarily deforestation . Over 70% of mammal species are in the orders Rodentia , Chiroptera , and Eulipotyphla . Mammal classification has been through several revisions since Carl Linnaeus initially defined the class, and at present , no classification system is universally accepted. McKenna & Bell (1997) and Wilson & Reeder (2005) provide useful recent compendiums. Simpson (1945) provides systematics of mammal origins and relationships that had been taught universally until
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#17327801112531826-489: 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
1909-426: Is the viviparous placental mammals , so named for the temporary organ ( placenta ) used by offspring to draw nutrition from the mother during gestation . Most mammals are intelligent , with some possessing large brains, self-awareness , and tool use . Mammals can communicate and vocalize in several ways, including the production of ultrasound , scent marking , alarm signals , singing , echolocation ; and, in
1992-404: 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
2075-643: 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
2158-776: 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
2241-472: 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
2324-646: 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
2407-671: 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
2490-473: The Cretaceous . The relationships between these three lineages is contentious, and all three possible hypotheses have been proposed with respect to which group is basal . These hypotheses are Atlantogenata (basal Boreoeutheria), Epitheria (basal Xenarthra) and Exafroplacentalia (basal Afrotheria). Boreoeutheria in turn contains two major lineages— Euarchontoglires and Laurasiatheria . Estimates for
2573-564: The International Union for Conservation of Nature (IUCN) completed a five-year Global Mammal Assessment for its IUCN Red List , which counted 5,488 species. According to research published in the Journal of Mammalogy in 2018, the number of recognized mammal species is 6,495, including 96 recently extinct. The word " mammal " is modern, from the scientific name Mammalia coined by Carl Linnaeus in 1758, derived from
Banded penguin - Misplaced Pages Continue
2656-556: The Latin mamma ("teat, pap"). In an influential 1988 paper, Timothy Rowe defined Mammalia phylogenetically as the crown group of mammals, the clade consisting of the most recent common ancestor of living monotremes ( echidnas and platypuses ) and therian mammals ( marsupials and placentals ) and all descendants of that ancestor. Since this ancestor lived in the Jurassic period, Rowe's definition excludes all animals from
2739-623: 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
2822-606: The biological classification scheme used, are the primates : apes , monkeys , and lemurs ; the Cetartiodactyla : whales and even-toed ungulates ; and the Carnivora which includes cats , dogs , weasels , bears , seals , and allies. According to Mammal Species of the World , 5,416 species were identified in 2006. These were grouped into 1,229 genera , 153 families and 29 orders. In 2008,
2905-406: The dominant terrestrial animal group from 66 million years ago to the present. The basic mammalian body type is quadrupedal , with most mammals using four limbs for terrestrial locomotion ; but in some, the limbs are adapted for life at sea , in the air , in trees or underground . The bipeds have adapted to move using only the two lower limbs, while the rear limbs of cetaceans and
2988-630: 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
3071-494: 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
3154-428: The rodents , bats , and Eulipotyphla (including hedgehogs , moles and shrews ). The next three are the primates (including humans , monkeys and lemurs ), the even-toed ungulates (including pigs , camels , and whales ), and the Carnivora (including cats , dogs , and seals ). Mammals are the only living members of Synapsida ; this clade , together with Sauropsida (reptiles and birds), constitutes
3237-439: The sea cows are mere internal vestiges . Mammals range in size from the 30–40 millimetres (1.2–1.6 in) bumblebee bat to the 30 metres (98 ft) blue whale —possibly the largest animal to have ever lived. Maximum lifespan varies from two years for the shrew to 211 years for the bowhead whale . All modern mammals give birth to live young, except the five species of monotremes , which lay eggs. The most species-rich group
3320-558: The syrinx , located at the bottom of the trachea. These penguins are sometimes referred to as "jack-ass" penguins, since their vocalizations tend to sound similar to a donkey braying. Vocalizations in adult penguins can be classified into 4 distinct categories based on its acoustic properties and the behavioural context in which a vocalization is produced. The 4 categories of vocalizations include contact calls, agonistic calls, ecstatic display songs or mutual display songs. Contact calls are vocalizations used primarily to maintain unity within
3403-579: 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
Banded penguin - Misplaced Pages Continue
3486-726: The French zoologist Mathurin Jacques Brisson in 1760 with the African penguin ( Spheniscus demersus ) as the type species . The genus name Spheniscus is derived from the Ancient Greek word σφήν ( sphẽn ) meaning "wedge" and is a reference to the animal's thin, wedge-shaped flippers. The four extant species of banded penguins ( Spheniscus ) are: [REDACTED] [REDACTED] [REDACTED] [REDACTED] Several extinct species are known from fossils: The former Spheniscus predemersus
3569-795: The Humboldt penguin lives in coastal Peru and Chile while the Magellanic penguin lives in coastal Chile, Argentina , and the Falkland Islands . Humboldt and Magellanic penguins are partially sympatric , since their ranges overlap in southern Chile . The Galápagos penguin is endemic to the Galápagos Islands , making it the most northerly of all penguin species. Banded penguins use vocalizations for localization, socialization and to allow recognition for conspecifics or mates. Vocalizations in birds are produced by vibrations of
3652-526: 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
3735-542: 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
3818-683: 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
3901-542: 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
3984-533: 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
4067-492: The case of humans, complex language . Mammals can organize themselves into fission–fusion societies , harems , and hierarchies —but can also be solitary and territorial . Most mammals are polygynous , but some can be monogamous or polyandrous . Domestication of many types of mammals by humans played a major role in the Neolithic Revolution , and resulted in farming replacing hunting and gathering as
4150-421: 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
4233-812: The clade originating with the last common ancestor of Sinoconodon and living mammals. The earliest-known synapsid satisfying Kemp's definitions is Tikitherium , dated 225 Ma , so the appearance of mammals in this broader sense can be given this Late Triassic date. However, this animal may have actually evolved during the Neogene. As of the early 21st century, molecular studies based on DNA analysis have suggested new relationships among mammal families. Most of these findings have been independently validated by retrotransposon presence/absence data . Classification systems based on molecular studies reveal three major groups or lineages of placental mammals— Afrotheria , Xenarthra and Boreoeutheria —which diverged in
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#17327801112534316-444: The closest thing to an official classification of mammals, despite its known issues. Most mammals, including the six most species-rich orders , belong to the placental group. The three largest orders in numbers of species are Rodentia : mice , rats , porcupines , beavers , capybaras , and other gnawing mammals; Chiroptera : bats; and Eulipotyphla : shrews , moles , and solenodons . The next three biggest orders, depending on
4399-585: The earlier Triassic , despite the fact that Triassic fossils in the Haramiyida have been referred to the Mammalia since the mid-19th century. If Mammalia is considered as the crown group, its origin can be roughly dated as the first known appearance of animals more closely related to some extant mammals than to others. Ambondro is more closely related to monotremes than to therian mammals while Amphilestes and Amphitherium are more closely related to
4482-517: 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
4565-600: 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
4648-451: The end of the 20th century. However, since 1945, a large amount of new and more detailed information has gradually been found: The paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself, partly through the new concept of cladistics . Though fieldwork and lab work progressively outdated Simpson's classification, it remains
4731-402: 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
4814-475: 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
4897-472: 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
4980-442: 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
5063-400: 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
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#17327801112535146-612: The larger Amniota clade. Early synapsids are referred to as " pelycosaurs ." The more advanced therapsids became dominant during the Guadalupian . Mammals originated from cynodonts , an advanced group of therapsids, during the Late Triassic to Early Jurassic . Mammals achieved their modern diversity in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs , and have been
5229-414: 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
5312-451: The mating pair and their offspring are the only individuals allowed on their nest. Thus, any conspecific from the large colony that intrudes this territory will be a threat and an agonistic call will be produced. There are two types of display songs vocalized by banded penguins; ecstatic display songs and mutual display songs. Ecstatic display songs are the loudest and most complex vocalization performed by banded penguins. They are composed of
5395-607: 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
5478-652: 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
5561-473: 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
5644-414: The penguins sex, age, social status within a group and emotional state. Agonistic calls are vocalizations used when a banded penguin is demonstrating agonistic behaviour , which is characterized by aggressive interactions or fighting. Typically, banded penguins vocalize agonistic calls when defending a territory, such as their nest, against conspecifics. For nesting penguin species, such as banded penguins,
5727-408: 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
5810-594: 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
5893-400: 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
5976-716: The primary source of food for humans. This led to a major restructuring of human societies from nomadic to sedentary, with more co-operation among larger and larger groups, and ultimately the development of the first civilizations . Domesticated mammals provided, and continue to provide, power for transport and agriculture, as well as food ( meat and dairy products ), fur , and leather . Mammals are also hunted and raced for sport, kept as pets and working animals of various types, and are used as model organisms in science. Mammals have been depicted in art since Paleolithic times, and appear in literature, film, mythology, and religion. Decline in numbers and extinction of many mammals
6059-518: 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
6142-544: 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
6225-641: 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
6308-548: The therians; as fossils of all three genera are dated about 167 million years ago in the Middle Jurassic , this is a reasonable estimate for the appearance of the crown group. T. S. Kemp has provided a more traditional definition: " Synapsids that possess a dentary – squamosal jaw articulation and occlusion between upper and lower molars with a transverse component to the movement" or, equivalently in Kemp's view,
6391-556: 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
6474-446: The vicinity assist the defending mother in keeping her chick. In some species, such as emperor and king penguins, the chicks assemble in large groups called crèches . Mammal A mammal (from Latin mamma 'breast') is a vertebrate animal of the class Mammalia ( / m ə ˈ m eɪ l i . ə / ). Mammals are characterized by the presence of milk -producing mammary glands for feeding their young,
6557-491: 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
6640-417: 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
6723-645: 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
6806-770: 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
6889-606: 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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