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  • Penguins 

    Penguins are a group of aquatic flightless birds from the family Spheniscidae (/sfɪˈnɪsɪdiː, -daɪ/) of the order Sphenisciformes (/sfɪˈnɪsəfɔːrmiːz/).[4] 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 krillfishsquid and other forms of sea life which they catch with their bills and swallow whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey.[5]

    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):[6] 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 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).[7] 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.[8] There was a great diversity of species in subantarctic regions, and at least one giant species in a region around 2,000 km south of the equator 35 mya, during the Late Eocene, a climate decidedly warmer than today.[9]

    Etymology

    The name penguin was first used in the late 16th century for the Great Auk (pictured here) and was later applied to Southern Hemisphere birds due to their resemblance, though they are not closely related.[10]

    The word penguin first appears in literature at the end of the 16th century as a synonym for the great auk.[11] When European explorers discovered what are today known as penguins in the Southern Hemisphere, they noticed their similar appearance to the great auk of the Northern Hemisphere and named them after this bird, although they are not closely related.[12]

    The etymology of the word penguin is still debated. The English word is not apparently of French,[13] Breton[14] or Spanish[15] origin (the latter two are attributed to the French word pingouin), but first appears in English or Dutch.[13]

    Some dictionaries suggest a derivation from Welsh pen, ‘head’ and gwyn, ‘white’,[16] including the Oxford English Dictionary, the American Heritage Dictionary,[17] the Century Dictionary[17] and Merriam-Webster,[18] on the basis that the name was originally applied to the great auk, either because it was found on White Head Island (WelshPen 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 a maritime context, pen blaen means ‘front end or part, bow (of a ship), prow’.[19]

    An alternative etymology links the word to Latin pinguis, which means ‘fat’ or ‘oil’.[20] 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; a group of penguins on land is a waddle, and a group of penguins in the water is a raft.

    Pinguinus

    Main article: Great auk

    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“),[10] which became extinct in the mid-19th century.[11] As confirmed by a 2004 genetic study, the genus Pinguinus belongs in the family of the auks (Alcidae), within the order of the Charadriiformes.[21][22]

    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.[12][10] They do not belong in the genus Pinguinus, and are not classified in 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.

    Systematics and evolution

    Taxonomy

    Main article: List of penguins

    The family name of Spheniscidae was given by Charles Lucien Bonaparte from the genus Spheniscus,[23] the name of that genus comes from the Greek word σφήν sphēn “wedge” used for the shape of an African penguin‘s swimming flippers.[24]

    Some recent sources[3][25] apply 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,[25] 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 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.[26] The International Ornithologists’ Union recognizes six genera and eighteen species:[27]

    GenusSpeciesImage of type species
    EudyptesMacaroni penguin (E. chrysolophus)Royal penguin (E. schlegeli)Northern rockhopper penguin (E. moseleyi)Southern rockhopper penguin (E. chrysocome)Fiordland penguin (E. pachyrhynchus)Snares penguin (E. robustus)Erect-crested penguin (E. sclateri)
    Southern rockhopper penguin
    SpheniscusGalapagos penguin (S. mendiculus)Humboldt penguin (S. humboldti)Magellanic penguin (S. magellanicus)African penguin (S. demersus)
    African penguin
    PygoscelisAdélie penguin (P. adeliae)Chinstrap penguin (P. antarcticus)Gentoo penguin (P. papua)
    Chinstrap penguin
    AptenodytesKing penguin (A. patagonicus)Emperor penguin (A.forsteri)
    King penguin
    EudyptulaLittle penguin (E. minor)
    Little penguin
    MegadyptesYellow-eyed penguin (M. antipodes)
    Yellow-eyed penguin

    Evolution

    Penguin tracks in the sand on Bruny IslandTasmania

    Although the evolutionary and biogeographic history of Sphenisciformes is well-researched, many prehistoric forms are not fully described. Some seminal articles about the evolutionary history of penguins have been published since 2005.[3][28][29][30][excessive citations]

    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.[3] 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 the CampanianMaastrichtian boundary, around 70–68 mya.[28][30][31]

    Basal fossils

    The oldest known fossil penguin species is Waimanu manneringi, which lived 62 mya in New Zealand.[30] While they were not as well-adapted to aquatic life as modern penguins, Waimanu were flightless, with short wings adapted for deep diving.[30] 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.[32]

    Perudyptes from northern Peru was dated to 42 mya. An unnamed fossil from Argentina proves that, by the Bartonian (Middle Eocene), some 39–38 mya,[33] primitive penguins had spread to South America and were in the process of expanding into Atlantic waters.[25]

    Palaeeudyptines

    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 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 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).[34] It is not known whether 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).[3] 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 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.[28] 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 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.

    Origin and systematics of modern penguins

    Modern penguins constitute two undisputed clades and another two more basal genera with more ambiguous relationships.[29] 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.[35] The origin of 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.[28] Presumably diverging from other penguins around 40 mya,[28] it seems that the Spheniscinae were for quite some time limited to their ancestral area, as the well-researched deposits of 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.[3][36] They have bright yellow-orange neck, breast, and bill patches; incubate by placing their eggs on their feet, and when they hatch 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 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,[37] 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.[28]

    The genera Spheniscus and Eudyptula contain species with 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 the Chattian (Late Oligocene), starting approximately 28 mya.[28] 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.[28]

    The MegadyptesEudyptes 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 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.[28]

    Geography

    The geographical and temporal pattern of spheniscine evolution corresponds closely to two episodes of global cooling documented in the paleoclimatic record.[28] The emergence of 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.[38] Notably, the cold Antarctic Circumpolar Current also started as 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.[28] 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.[38]

    Later, an interspersed period of slight warming 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.

    Relationship to other bird orders

    Penguin ancestry beyond Waimanu remains unknown and not well-resolved by molecular or morphological analyses. The latter tend to be confounded by 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.

    Humboldt penguins in an aquarium. The penguin is an accomplished swimmer, having flippers instead of wings.

    What seems clear is that penguins belong to a clade of Neoaves (living birds except for paleognaths and fowl) that comprises what is sometimes called “higher waterbirds” to distinguish them from the more ancient waterfowl. This group contains such birds as storksrails, and the seabirds, with the possible exception of the Charadriiformes.[39]

    Inside this group, penguin relationships are far less clear. Depending on the analysis and dataset, a close relationship to Ciconiiformes[30] or to Procellariiformes[28] has been suggested. Some think 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 the traditional Pelecaniformes into three.[40]

    A 2014 analysis of whole genomes of 48 representative bird species has concluded that penguins are the sister group of Procellariiformes,[41] from which they diverged about 60 million years ago (95% CI, 56.8–62.7).[42]

    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 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.[43]

    Anatomy and physiology

    Penguin wings have the same general bone structure as flighted birds, but the bones are shorter and stouter to allow them to serve as fins. 1). Humerus 2). Sesamoid Bone 3). Radius 4). Ulna 5). Radial Carpal bone 6). Carpometacarpus 7). Phalanges
    Taxidermized penguin skin

    Penguins are superbly adapted to aquatic life. Their wings have evolved to become flippers, useless for flight in the air. In the water, however, penguins are astonishingly agile. Penguins’ swimming looks very similar to birds’ flight in the air.[44] 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.[45] A predator looking up from below (such as an orca or 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).[46] The small penguins do not usually dive deep; they catch their prey near 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.[47]

    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;[48] this is used by parents and chicks to locate one another in crowded colonies.[49] 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.[50]

    Gentoo penguin swimming underwater at the Nagasaki Penguin Aquarium

    Penguins have a thick layer of insulating feathers that keeps them warm in water (heat loss in water 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 afterfeathersplumules, and filoplumes. The afterfeathers are downy plumes that attach directly to 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 was and whether or not it needed preening, so their presence in penguins may seem inconsistent, but penguins also preen extensively.[51]

    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 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[52] suggest that most extant penguins are too small to survive in such cold environments.[53] In 2007, Thomas and Fordyce wrote about the “heterothermic loophole” that penguins utilize in order to survive in Antarctica.[54] 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 the extreme cold.[55]

    They can drink salt water because their supraorbital gland filters excess salt from the bloodstream.[56][57][58] 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 the penguins, but are an example of convergent evolution.[59]

    An isabelline Adélie penguin on Gourdin Island

    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.

    Behaviour

    Duration: 49 seconds.0:49Chinstrap penguins in Antarctica

    Breeding

    Gentoo penguin watching over a sleeping chick at Brown Bluff

    Gentoo penguin watching over a sleeping chick at Brown Bluff

    Penguins for 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.[60] 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.[61] Agonistic displays are those intended to confront or drive off, or alternately appease and avoid conflict with, other individuals.[61]

    Penguins form monogamous pairs for 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.[62] With the exception of the emperor penguin, where the male does it all, all penguins share the incubation duties.[63] These incubation shifts can last days and even weeks as one member of the pair feeds at sea.

    Penguins generally only lay one brood; the exception is the little penguin, which can raise two or three broods in a season.[64]

    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%.[62] The relatively thick shell forms between 10 and 16% of 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.[65] 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.[66]

    When emperor penguin mothers lose a chick, they sometimes attempt to “steal” another mother’s chick, usually unsuccessfully as other females in the vicinity assist the defending mother in keeping her chick.[67] In some species, such as emperor and king penguins, the chicks assemble in large groups called crèches.

    Distribution and habitat

    See also: List of Sphenisciformes by population

    Although almost all penguin species are native to the Southern Hemisphere, they are not found only in cold climates, such as Antarctica. In fact, only a few species of penguin actually live so far south. Several species live in the temperate zone;[68][failed verification] one, the Galápagos penguin, lives as far north as the Galápagos Islands, but this is only made possible by the cold, rich waters of the Antarctic Humboldt Current that flows around these islands.[69] Also, though the climate of the Arctic and Antarctic regions is similar, there are no penguins found in the Arctic.[70]

    Gálapagos Penguins near Isabela Island

    Several authors have suggested that penguins are a good example of Bergmann’s Rule[71][72] where larger-bodied populations live at higher latitudes than smaller-bodied populations. There is some disagreement about this and several other authors have noted that there are fossil penguin species that contradict this hypothesis and that ocean currents and upwellings are likely to have had a greater effect on species diversity than latitude alone.[73][74]

    Major populations of penguins are found in AngolaAntarcticaArgentinaAustraliaChileNamibiaNew Zealand, and South Africa.[75][76] Satellite images and photos released in 2018 show the population of 2 million in France‘s remote Ile aux Cochons has collapsed, with barely 200,000 remaining, according to a study published in Antarctic Science.[77]

    Conservation status

    The majority of living penguin species have declining populations. According to the IUCN Red List, their conservation statuses range from Least Concern through to Endangered.

    SpeciesIUCN Red List StatusTrendMature IndividualsLast assessment
    Emperor penguinAptenodytes forsteriNear ThreatenedUnknown2018[78]
    King penguinAptenodytes patagonicusLeast ConcernIncreasing2018[79]
    Little penguinEudyptula minorLeast ConcernStable469,7602018[80]
    Southern rockhopper penguinEudyptes chrysocomeVulnerableDecreasing2,500,0002018[81]
    Macaroni penguinEudyptes chrysolophusVulnerableDecreasing2018[82]
    Northern rockhopper penguinEudyptes moseleyiEndangeredDecreasing480,6002018[83]
    Fiordland penguinEudyptes pachyrynchusVulnerableDecreasing2,500–9,9992018[84]
    Snares penguinEudyptes robustusVulnerableStable63,0002018[85]
    Royal penguinEudyptes schlegeli (disputed)Near ThreatenedStable1,700,0002018[86]
    Erect-crested penguinEudyptes sclateriEndangeredDecreasing150,0002016[87]
    Yellow-eyed penguinMegadyptes antipodesEndangeredDecreasing2,528–3,4802018[88]
    Adélie penguinPygoscelis adeliaeLeast ConcernIncreasing7,580,0002018[89]
    Chinstrap penguinPygoscelis antarcticaLeast ConcernDecreasing8,000,0002018[90]
    Gentoo penguinPygoscelis papuaLeast ConcernStable774,0002018[91]
    African penguinSpheniscus demersusCritically EndangeredDecreasing19,8002024[92]
    Humboldt penguinSpheniscus humboldtiVulnerableDecreasing32,0002018[93]
    Magellanic penguinSpheniscus magellanicusNear ThreatenedDecreasing2018[94]
    Galápagos penguinSpheniscus mendiculusEndangeredDecreasing1,2002018[95]

    Penguins and humans

    The cook on the Endurance preparing an emperor penguin for consumption.
    An Adélie penguin encountering a human during the Antarctic summer

    Penguins have no special fear of humans and will often approach groups of people. This is probably because penguins have no land predators in Antarctica or the nearby offshore islands. They are preyed upon by other birds like skuas, especially in eggs and as fledglings. Other birds like petrels, sheathbills, and gulls also eat the chicks. Dogs preyed upon penguins while they were allowed in Antarctica during the age of early human exploration as sled dogs, but dogs have long since been banned from Antarctica.[96] Instead, adult penguins are at risk at sea from predators such as sharksorcas, and leopard seals. Typically, penguins do not approach closer than around 9 feet (2.7 meters), at which point they appear to become nervous.[97]

    In June 2011, an emperor penguin came ashore on New Zealand’s Peka Peka Beach, 3,200 kilometres (2,000 mi) off course on its journey to Antarctica.[98] Nicknamed Happy Feet, after the film of the same name, it was suffering from heat exhaustion and had to undergo a number of operations to remove objects like driftwood and sand from its stomach.[99] Happy Feet was a media sensation, with extensive coverage on TV and the web, including a live stream that had thousands of views[100] and a visit from English actor Stephen Fry.[101] Once he had recovered, Happy Feet was released back into the water south of New Zealand.[102]

    Main article: Cultural depictions of penguins

    Tux, the mascot of the Linux kernel

    Penguins are widely considered endearing for their unusually upright, waddling gait, swimming ability and (compared to other birds) lack of fear of humans. Their black-and-white plumage is often likened to a white tie suit. Some writers and artists have penguins based at the North Pole, but there are no wild penguins in the Arctic. The cartoon series Chilly Willy helped perpetuate this myth, as the title penguin would interact with Arctic or sub-Arctic species, such as polar bears and walruses.

    Penguins have been the subject of many books and films, such as Happy FeetSurf’s Up and Penguins of Madagascar, all CGI films; March of the Penguins, a documentary based on the migration process of the emperor penguin; and Farce of the Penguins, a parody of the documentary. Mr. Popper’s Penguins is a children’s book written by Richard and Florence Atwater; it was named a Newbery Honor Book in 1939. Penguins have also appeared in a number of cartoons and television dramas, including Pingu, co-created by Otmar Gutmann and Erika Brueggemann in 1990 and covering more than 100 short episodes. At the end of 2009, Entertainment Weekly put it on its end-of-the-decade “best-of” list, saying, “Whether they were walking (March of the Penguins), dancing (Happy Feet), or hanging ten (Surf’s Up), these oddly adorable birds took flight at the box office all decade long.”[103]

    A video game called Pengo was released by Sega in 1982. Set in Antarctica, the player controls a penguin character who must navigate mazes of ice cubes. The player is rewarded with cut-scenes of animated penguins marching, dancing, saluting and playing peekaboo. Several remakes and enhanced editions have followed, most recently in 2012. Penguins are also sometimes depicted in music.[104]

    In 1941, DC Comics introduced the avian-themed character of the Penguin as a supervillain adversary of the superhero Batman (Detective Comics #58). He became one of the most enduring enemies in Batman’s rogues gallery. In the 60s Batman TV series, as played by Burgess Meredith, he was one of the most popular characters, and in Tim Burton‘s reimagining of the story, the character played by Danny Devito in the 1992 film Batman Returns, employed an actual army of penguins (mostly African penguins and king penguins).

    Several pro, minor, college and high school sport teams in the United States have named themselves after the species, including the Pittsburgh Penguins team in the National Hockey League and the Youngstown State Penguins in college athletics.

    Penguins featured regularly in the cartoons of U.K. cartoonist Steve Bell in his strip in The Guardian newspaper, particularly during and following the Falklands WarOpus the Penguin, from the cartoons of Berkeley Breathed, is also described as hailing from the Falklands. Opus was a comical, “existentialist” penguin character in the cartoons Bloom CountyOutland and Opus. He was also the star in the animated Christmas TV special A Wish for Wings That Work.

    In the mid-2000s, penguins became one of the most publicized species of animals that form lasting homosexual couples. A children’s bookAnd Tango Makes Three, was written about one such penguin family in the New York Zoo.

  • Panda

    The giant panda (Ailuropoda melanoleuca), also known as the panda bear or simply panda, is a bear species endemic to China. It is characterised by its white coat with black patches around the eyes, ears, legs and shoulders. Its body is rotund; adult individuals weigh 100 to 115 kg (220 to 254 lb) and are typically 1.2 to 1.9 m (3 ft 11 in to 6 ft 3 in) long. It is sexually dimorphic, with males being typically 10 to 20% larger than females. A thumb is visible on its forepaw, which helps in holding bamboo in place for feeding. It has large molar teeth and expanded temporal fossa to meet its dietary requirements. It can digest starch and is mostly herbivorous with a diet consisting almost entirely of bamboo and bamboo shoots.

    The giant panda lives exclusively in six montane regions in a few Chinese provinces at elevations of up to 3,000 m (9,800 ft). It is solitary and gathers only in mating seasons. It relies on olfactory communication to communicate and uses scent marks as chemical cues and on landmarks like rocks or trees. Females rear cubs for an average of 18 to 24 months. The oldest known giant panda was 38 years old.

    As a result of farming, deforestation and infrastructural development, the giant panda has been driven out of the lowland areas where it once lived. The wild population has increased again to 1,864 individuals as of March 2015. Since 2016, it has been listed as Vulnerable on the IUCN Red List. In July 2021, Chinese authorities also classified the giant panda as vulnerable. It is a conservation-reliant species. By 2007, the captive population comprised 239 giant pandas in China and another 27 outside the country. It has often served as China’s national symbol, appeared on Chinese Gold Panda coins since 1982 and as one of the five Fuwa mascots of the 2008 Summer Olympics held in Beijing.

    Etymology

    The word panda was borrowed into English from French, but no conclusive explanation of the origin of the French word panda has been found.[3] The closest candidate is the Nepali word ponya, possibly referring to the adapted wrist bone of the red panda, which is native to Nepal. In many older sources, the name “panda” or “common panda” refers to the red panda (Ailurus fulgens),[4] which was described some 40 years earlier and over that period was the only animal known as a panda.[5] The binomial name Ailuropoda melanoleuca means black and white (melanoleuca) cat-foot (ailuropoda).[6]

    Since the earliest collection of Chinese writings, the Chinese language has given the bear many different names, including  (貘, ancient Chinese name for giant panda),[7] huāxióng (花熊; “spotted bear”) and zhúxióng (竹熊; “bamboo bear”).[8] The most popular names in China today are dàxióngmāo (大熊貓; lit. ’giant bear cat’), or simply xióngmāo (熊貓; lit. ’bear cat’). As with the word panda in English, xióngmāo (熊貓) was originally used to describe just the red panda, but dàxióngmāo (大熊貓) and xiǎoxióngmāo (小熊猫; lit. ’little bear cat’) were coined to differentiate between the species.[8]

    In Taiwan, another popular name for panda is the inverted dàmāoxióng (大貓熊; lit. ’giant cat bear’), though many encyclopedias and dictionaries in Taiwan still use the “bear cat” form as the correct name. Some linguists argue, in this construction, “bear” instead of “cat” is the base noun, making the name more grammatically and logically correct, which have led to the popular choice despite official writings.[8] This name did not gain its popularity until 1988, when a private zoo in Tainan painted a sun bear black and white and created the Tainan fake panda incident.[9][10]

    Taxonomy

    For many decades, the precise taxonomic classification of the giant panda was under debate because it shares characteristics with both bears and raccoons.[11] In 1985, molecular studies indicated that the giant panda is a true bear, part of the family Ursidae.[12][13] These studies show it diverged about 19 million years ago from the common ancestor of the Ursidae;[14] it is the most basal member of this family and equidistant from all other extant bear species.[14][15]

    Subspecies

    The Qinling panda has a light brown-and-white pattern

    Two subspecies of giant panda have been recognized on the basis of distinct cranial measurements, colour patterns, and population genetics.[16]

    • The nominate subspeciesA. m. melanoleuca, consists of most extant populations of the giant panda. These animals are principally found in Sichuan and display the typical stark black and white contrasting colours.[17]
    • The Qinling pandaA. m. qinlingensis,[18] is restricted to the Qinling Mountains in Shaanxi at elevations of 1,300–3,000 m (4,300–9,800 ft). The typical black and white pattern of Sichuan giant pandas is replaced with a light brown and white pattern.[16] The skull of A. m. qinlingensis is smaller than its relatives, and it has larger molars.[19]

    A detailed study of the giant panda’s genetic history from 2012 confirms that the separation of the Qinling population occurred about 300,000 years ago, and reveals that the non-Qinling population further diverged into two groups, named the Minshan and the QionglaiDaxianglingXiaoxianglingLiangshan group respectively, about 2,800 years ago.[20]

    Phylogeny

    Of the eight extant species in the bear family Ursidae, the giant panda’s lineage branched off the earliest.[21][22]

    UrsidaeGiant panda (Ailuropoda melanoleucaSpectacled bear (Tremarctos ornatusUrsinae (black, brown, sloth, sun, and polar bears) 

    Distribution and habitat

    The giant panda is endemic to China. It is found in small, fragmented populations in six mountainous regions in the country, mainly in Sichuan, and also in neighbouring Shaanxi and Gansu.[23] Successful habitat preservation has seen a rise in panda numbers, though loss of habitat due to human activities remains its biggest threat. In areas with a high concentration of medium-to-large-sized mammals—such as domestic cattle, a species known to degrade the landscape—the giant panda population is generally low. This is mainly attributed to the panda’s avoidance of interspecific competition.[24][25]

    The species has been located at elevations of 2,400 to 3,000 m (7,900 to 9,800 ft) above sea level.[26] They frequent habitats with a healthy concentration of bamboos, typically old-growth forests, but may also venture into secondary forest habitats.[27] The Daxiangling Mountain population inhabits both coniferous and broadleaf forests.[28] Additionally, the Qinling population often selects evergreen broadleaf and conifer forests, while pandas in the Qionglai mountainous region exclusively select upland conifer forests. The remaining two populations, namely those occurring in the Liangshan and Xiaoxiangling mountains, predominantly occur in broadleaf evergreen and conifer forests.[12]: 137–148 

    Giant pandas once roamed across Southeast Asia from Myanmar to northern Vietnam. Their range in China spanned much of the southeast region. By the Pleistocene, climate change affected panda populations, and the subsequent domination of modern humans led to large-scale habitat loss.[29][30] In 2001, it was estimated that the range of the giant panda had declined by about 99% of its range in earlier millenniums.[31]

    Description

    The skull of a giant panda at the Smithsonian Museum of Natural History

    Close-up of giant panda at ZooParc in Beauval, France

    The giant panda has a body shape typical of bears. It has black fur on its ears, limbs, shoulders and around the eyes. The rest of the animal’s coat is white.[32] The bear’s distinctive coloration appears to serve as camouflage in both winter and summer environments as they do not hibernate. The white areas serve as camouflage in snow, while the black shoulders and legs conceal them in shade.[33] Studies in the wild have found that when viewed from a distance, the panda displays disruptive coloration, while up close, they rely more on blending in.[34] The black ears may be used to display aggression,[33] while the eye patches might facilitate them identifying one another.[33][35] The giant panda’s thick, woolly coat keeps it warm in the cool forests of its habitat.[32]

    The panda’s skull shape is typical of durophagous carnivorans. It has evolved from previous ancestors to exhibit larger molars with increased complexity and expanded temporal fossa.[36][37] A study revealed that a 117.5 kg (259 lb) giant panda had a bite force of 1298.9 Newton (BFQ 151.4) at canine teeth and 1815.9 Newton (BFQ 141.8) at carnassial teeth.[38] Adults measure around 1.2 to 1.9 m (3 ft 11 in to 6 ft 3 in) long, including a tail of about 10–15 cm (3.9–5.9 in), and 60 to 90 cm (24 to 35 in) tall at the shoulder.[39][40] Males can weigh up to 160 kg (350 lb).[41] Females are generally 10–20% smaller than males.[42] They weigh between 70 kg (150 lb) and 125 kg (276 lb).[43][39][44] The average weight for adults is 100 to 115 kg (220 to 254 lb).[45]

    The giant panda’s paw has a digit similar to a thumb and five fingers; the thumb-like digit – actually a modified sesamoid bone – helps it to hold bamboo while eating.[46][47] The giant panda’s tail, measuring 10 to 15 cm (3.9 to 5.9 in), is the second-longest in the bear family, behind the sloth bear.[42]

    Ecology

    Diet

    Pandas eating bamboo

    Duration: 34 seconds.0:34Subtitles available.CCPandas eating, standing, and playing

    Despite its taxonomic classification as a carnivoran, the giant panda’s diet is primarily herbivorous, with approximately 99% of its diet consisting of bamboo.[48] However, the giant panda still has the digestive system of a carnivore, as well as carnivore-specific genes,[49] and thus derives little energy and little protein from the consumption of bamboo. The ability to break down cellulose and lignin is very weak, and their main source of nutrients comes from starch and hemicelluloses. The most important part of their bamboo diet is the shoots, that are rich in starch and have up to 32% protein content. Accordingly, pandas have evolved a higher capability to digest starches than strict carnivores.[50] Raw bamboo is toxic, containing cyanide compounds. Pandas’ body tissues are less able than herbivores to detoxify cyanide, but their gut microbiomes are significantly enriched in putative genes coding for enzymes related to cyanide degradation, suggesting that they have cyanide-digesting gut microbes.[51] It has been estimated that an adult panda absorbs 54.8–66.1 mg (0.846–1.020 gr) of cyanide a day through its diet. To prevent poisoning, they have evolved anti-toxic mechanisms to protect themselves. About 80% of the cyanide is metabolized to less toxic thiocyanate and discharged in urine, while the remaining 20% is detoxified by other minor pathways.[52]

    During the shoot season (April–August), pandas store a large amount of food in preparation for the months succeeding this seasonal period, in which pandas live off a diet of bamboo leaves.[53] The giant panda is a highly specialised animal with unique adaptations, and has lived in bamboo forests for millions of years.[54] The average giant panda eats as much as 9 to 14 kg (20 to 31 lb) of bamboo shoots a day to compensate for the limited energy content of its diet. Ingestion of such a large quantity of material is possible and necessary because of the rapid passage of large amounts of indigestible plant material through the short, straight digestive tract.[55][56] It is also noted, however, that such rapid passage of digesta limits the potential of microbial digestion in the gastrointestinal tract,[55] limiting alternative forms of digestion. Given this voluminous diet, the giant panda defecates up to 40 times a day.[57] The limited energy input imposed on it by its diet has affected the panda’s behavior. The giant panda tends to limit its social interactions and avoids steeply sloping terrain to limit its energy expenditures.[58]

    Two of the panda’s most distinctive features, its large size and round face, are adaptations to its bamboo diet. Anthropologist Russell Ciochon observed: “[much] like the vegetarian gorilla, the low body surface area to body volume [of the giant panda] is indicative of a lower metabolic rate. This lower metabolic rate and a more sedentary lifestyle allows the giant panda to subsist on nutrient poor resources such as bamboo.”[58] The giant panda’s round face is the result of powerful jaw muscles, which attach from the top of the head to the jaw.[58] Large molars crush and grind fibrous plant material.[59]

    A panda feeding on bamboo

    The morphological characteristics of extinct relatives of the giant panda suggest that while the ancient giant panda was omnivorous 7 million years ago (mya), it only became herbivorous some 2–2.4 mya with the emergence of A. microta.[59][60] Genome sequencing of the giant panda suggests that the dietary switch could have initiated from the loss of the sole umami taste receptor, encoded by the genes TAS1R1 and TAS1R3 (also known as T1R1 and T1R3), resulting from two frameshift mutations within the T1R1 exons.[49] Umami taste corresponds to high levels of glutamate as found in meat and may have thus altered the food choice of the giant panda.[61] Although the pseudogenisation (conversion into a pseudogene) of the umami taste receptor in Ailuropoda coincides with the dietary switch to herbivory, it is likely a result of, and not the reason for, the dietary change.[59][49][61] The mutation time for the T1R1 gene in the giant panda is estimated to 4.2 mya[59] while fossil evidence indicates bamboo consumption in the giant panda species at least 7 mya,[60] signifying that although complete herbivory occurred around 2 mya, the dietary switch was initiated prior to T1R1 loss-of-function.[62]

    Pandas eat any of 25 bamboo species in the wild, with the most common including Fargesia dracocephala[62] and Fargesia rufa.[63] Only a few bamboo species are widespread at the high altitudes pandas now inhabit. Bamboo leaves contain the highest protein levels; stems have less.[64] Because of the synchronous flowering, death, and regeneration of all bamboo within a species, the giant panda must have at least two different species available in its range to avoid starvation. While primarily herbivorous, the giant panda still retains decidedly ursine teeth and will eat meat, fish, and eggs when available. In captivity, zoos typically maintain the giant panda’s bamboo diet, though some will provide specially formulated biscuits or other dietary supplements.[65]

    Pandas will travel between different habitats if they need to, so they can get the nutrients that they need and to balance their diet for reproduction.[66]

    Interspecific interactions

    Although adult giant pandas have few natural predators other than humans, young cubs are vulnerable to attacks by snow leopardsyellow-throated martens,[67] eagles, feral dogs, and the Asian black bear. Sub-adults weighing up to 50 kg (110 lb) may be vulnerable to predation by leopards.[68]

    Giant pandas are sympatric with other large mammals and bamboo feeders, such as the takin (Budorcas taxicolor). The takin and giant panda share a similar ecological niche, and they consume the same resources. When competition for food is fierce, pandas disperse to the outskirts of takin distribution. Other possible competitors include but is not limited to, the Eurasian wild pig (Sus scrofa), Chinese goral (Naemorhedus griseus) and the Asian black bear (Ursus thibetanus). Giant pandas avoid areas with a mid-to-high density of livestock, as they depress the vegetation.[69] The Tibetan Plateau is the only known area where both giant and red pandas can be found. Although sharing near-identical ecological niches, competition between the two species has rarely been observed. Nearly 50% of their respective distribution overlaps, and successful coexistence is achieved through distinct habitat selection.[70]

    Pathogens and parasites

    A captive female died from toxoplasmosis, a disease caused by an obligate intracellular parasitic protozoan known as Toxoplasma gondii that infects most warm-blooded animals, including humans.[71] They are likely susceptible to diseases from Baylisascaris schroederi, a parasitic nematode known to infect giant panda intestines. This nematode species is known to give pandas baylisascariasi, a deadly disease that kills more wild pandas than any other cause. Additionally, the population is threatened by canine distemper virus (CDV)canine parvovirusrotaviruscanine adenovirus, and canine coronavirus. Bacteria, such as Clostridium welchiiProteus mirabilisKlebsiella pneumoniae, and Escherichia coli, may also be lethal.[72]

    Behavior

    The giant panda is a terrestrial animal and primarily spends its life roaming and feeding in the bamboo forests of the Qinling Mountains and in the hilly province of Sichuan.[73] Giant pandas are generally solitary.[54] Each adult has a defined territory and a female is not tolerant of other females in her range. Social encounters occur primarily during the brief breeding season in which pandas in proximity to one another will gather.[74] After mating, the male leaves the female alone to raise the cub.[32] Pandas were thought to fall into the crepuscular category, those who are active twice a day, at dawn and dusk; however, pandas may belong to a category all of their own, with activity peaks in the morning, afternoon and midnight. The low nutrition quality of bamboo means pandas need to eat more frequently, and due to their lack of major predators they can be active at any time of the day.[75] Activity is highest in June and decreases in late summer to autumn with an increase from November through the following March.[76] Activity is also directly related to the amount of sunlight during colder days.[76] There is a significant interaction of solar radiation, such that solar radiation has a stronger positive effect on activity levels of panda bears.[76]

    Pandas communicate through vocalisation and scent marking such as clawing trees or spraying urine.[43] They are able to climb and take shelter in hollow trees or rock crevices, but do not establish permanent dens. For this reason, pandas do not hibernate, which is similar to other subtropical mammals, and will instead move to elevations with warmer temperatures.[77] Pandas rely primarily on spatial memory rather than visual memory.[78] Though the panda is often assumed to be docile, it has been known to attack humans on rare occasions.[79][80][81] Pandas have been known to cover themselves in horse manure to protect themselves against cold temperatures.[82]

    The species communicates foremost through a blatting sound; they achieve peaceful interactions through the emission of this sound. When in oestrus, a female emits a chirp. In hostile confrontations or during fights, the giant panda emits vocalizations such as a roar or growl. On the other hand, squeals typically indicate inferiority and submission in a dispute. Other vocalizations include honks and moans.[83]

    Olfactory communication

    Giant pandas heavily rely on olfactory communication to communicate with one another. Scent marks are used to spread these chemical cues and are placed on landmarks like rocks or trees.[84] Chemical communication in giant pandas plays many roles in their social situations. Scent marks and odors are used to spread information about sexual status, whether a female is in estrus or not, age, gender, individuality, dominance over territory, and choice of settlement.[84] Giant pandas communicate by excreting volatile compounds, or scent marks, through the anogenital gland.[84][85] Giant pandas have unique positions in which they will scent mark. Males deposit scent marks or urine by lifting their hind leg, rubbing their backside, or standing in order to rub the anogenital gland onto a landmark. Females, however, exercise squatting or simply rubbing their genitals onto a landmark.[84][86]

    The season plays a major role in mediating chemical communication.[87] Depending on the season, mainly whether it is breeding season or not, may influence which odors are prioritized. Chemical signals can have different functions in different seasons. During the non-breeding season, females prefer the odors of other females because reproduction is not their primary motivation. However, during breeding season, odors from the opposite sex will be more attractive.[87][88] Because they are solitary mammals and their breeding season is so brief, female pandas secrete chemical cues in order to let males know their sexual status.[88] The chemical cues female pandas secrete can be considered to be pheromones for sexual reproduction.[88] Females deposit scent marks through their urine which induces an increase in androgen levels in males.[88] Androgen is a sex hormone found in both males and females; testosterone is the major androgen produced by males. Civetone and decanoic acid are chemicals found in female urine which promote behavioral responses in males; both chemicals are considered giant panda pheromones.[88] Male pandas also secrete chemical signals that include information about their sexual reproductivity and age, which is beneficial for a female when choosing a mate.[84][87] For example, age can be useful for a female to determine sexual maturity and sperm quality.[89] Pandas are also able to determine when the signal was placed, further aiding in the quest to find a potential mate.[89] However, chemical cues are not just used for communication between males and females, pandas can determine individuality from chemical signals. This allows them to be able to differentiate between a potential partner or someone of the same sex, which could be a potential competitor.[89]

    Chemical cues, or odors, play an important role in how a panda chooses their habitat. Pandas look for odors that tell them not only the identity of another panda, but if they should avoid them or not.[89] Pandas tend to avoid their species for most of the year, breeding season being the brief time of major interaction.[89] Chemical signaling allows for avoidance and competition.[86][87] Pandas whose habitats are in similar locations will collectively leave scent marks in a unique location which is termed “scent stations”.[89] When pandas come across these scent stations, they are able to identify a specific panda and the scope of their habitat. This allows pandas to be able to pursue a potential mate or avoid a potential competitor.[89]

    Pandas can assess an individual’s dominance status, including their age and size, via odor cues and may choose to avoid a scent mark if the signaler’s competitive ability outweighs their own.[86] A panda’s size can be conveyed through the height of the scent mark.[86][90] Since larger animals can place higher scent marks, an elevated scent mark advertises a higher competitive ability. Age must also be taken into consideration when assessing a competitor’s fighting ability. For example, a mature panda will be larger than a younger, immature panda and possess an advantage during a fight.[86]

    Reproduction

    A giant panda cub

    Giant pandas reach sexual maturity between the ages of four and eight, and may be reproductive until age 20.[91] The mating season is between March and May, when a female goes into estrus, which lasts for two or three days and only occurs once a year.[92] When mating, the female is in a crouching, head-down position as the male mounts her from behind. Copulation time ranges from 30 seconds to five minutes, but the male may mount her repeatedly to ensure successful fertilisation. The gestation period is somewhere between 95 and 160 days – the variability is due to the fact that the fertilized egg may linger in the reproductive system for a while before implanting on the uterine wall.[92] Giant pandas give birth to twins in about half of pregnancies.[93] If twins are born, usually only one survives in the wild. The mother will select the stronger of the cubs, and the weaker cub will die due to starvation. The mother is thought to be unable to produce enough milk for two cubs since she does not store fat.[94] The father has no part in helping raise the cub.[32]

    When the cub is first born, it is pink, blind, and toothless,[32] weighing only 90 to 130 g (3.2 to 4.6 oz), or about ⁠1/800⁠ of the mother’s weight,[11] proportionally the smallest baby of any placental mammal.[95] It nurses from its mother’s breast six to 14 times a day for up to 30 minutes at a time. For three to four hours, the mother may leave the den to feed, which leaves the cub defenseless. One to two weeks after birth, the cub’s skin turns grey where its hair will eventually become black. Slight pink colour may appear on the cub’s fur, as a result of a chemical reaction between the fur and its mother’s saliva. A month after birth, the colour pattern of the cub’s fur is fully developed. Its fur is very soft and coarsens with age. The cub begins to crawl at 75 to 80 days;[11] mothers play with their cubs by rolling and wrestling with them. The cubs can eat small quantities of bamboo after six months, though mother’s milk remains the primary food source for most of the first year. Giant panda cubs weigh 45 kg (99 lb) at one year and live with their mothers until they are 18 months to two years old. The interval between births in the wild is generally two years.[96]

    Initially, the primary method of breeding giant pandas in captivity was by artificial insemination, as they seemed to lose their interest in mating once they were captured.[97] This led some scientists to trying methods such as showing them videos of giant pandas mating[98] and giving the males sildenafil (commonly known as Viagra).[99] In the 2000s, researchers started having success with captive breeding programs, and they have now determined giant pandas have comparable breeding to some populations of the American black bear, a thriving bear species.[100][73]

    In July 2009, Chinese scientists confirmed the birth of the first cub to be successfully conceived through artificial insemination using frozen sperm.[101] The technique for freezing the sperm in liquid nitrogen was first developed in 1980 and the first birth was hailed as a solution to the dwindling availability of giant panda semen, which had led to inbreeding.[102][103] Panda semen, which can be frozen for decades, could be shared between different zoos to save the species.[101][104] As of 2009, it is expected that zoos in destinations such as San Diego in the United States and Mexico City will be able to provide their own semen to inseminate more giant pandas.[103]

    Attempts have also been made to reproduce giant pandas by interspecific pregnancy where cloned panda embryos were implanted into the uterus of an animal of another species. This has resulted in panda fetuses, but no live births.[105]

    Human interaction

    Early references

    Main article: Mo (Chinese zoology)

    In Ancient China, people thought pandas to be rare and noble creatures – the Empress Dowager Bo was buried with a panda skull in her vault. The grandson of Emperor Taizong of Tang is said to have given Japan two pandas and a sheet of panda skin as a sign of goodwill. Unlike many other animals in Ancient China, pandas were rarely thought to have medical uses. The few known uses include the Sichuan tribal peoples’ use of panda urine to melt accidentally swallowed needles, and the use of panda pelts to control menstruation as described in the Qin dynasty encyclopedia Erya.[106]

    The creature named mo (貘) mentioned in some ancient books has been interpreted as giant panda.[106] The dictionary Shuowen Jiezi (Eastern Han Dynasty) says that the mo, from Shu (Sichuan), is bear-like, but yellow-and-black,[107] although the older Erya describes mo simply as a “white leopard”.[108] The interpretation of the legendary fierce creature pixiu (貔貅) as referring to the giant panda is also common.[109]

    During the reign of the Yongle Emperor (early 15th century), his relative from Kaifeng sent him a captured zouyu (騶虞), and another zouyu was sighted in ShandongZouyu is a legendary “righteous” animal, which, similarly to a qilin, only appears during the rule of a benevolent and sincere monarch.[110]

    In captivity

    Main articles: Giant pandas around the worldList of giant pandas, and Panda diplomacy

    See also: Category:Individual giant pandas

    Pandas have been kept in zoos as early as the Western Han Dynasty in China, where the writer Sima Xiangru noted that the panda was the most treasured animal in the emperor’s garden of exotic animals in the capital Chang’an (present Xi’an). Not until the 1950s were pandas again recorded to have been exhibited in China’s zoos.[111] Chi Chi at the London Zoo became very popular. This influenced the World Wildlife Fund to use a panda as its symbol.[112] A 2006 New York Times article outlined the economics of keeping pandas,[113] which costs five times more than keeping the next most expensive animal, an elephant. American zoos generally pay the Chinese government $1 million a year in fees, as part of a typical ten-year contract. San Diego’s contract with China was to expire in 2008, but got a five-year extension at about half of the previous yearly cost.[114] The last contract, with the Memphis Zoo in Memphis, Tennessee, ended in 2013.[113]

    Adult male giant panda at the San Diego Zoo in 2004

    In the 1970s, gifts of giant pandas to American and Japanese zoos formed an important part of the diplomacy of the People’s Republic of China (PRC), as it marked some of the first cultural exchanges between China and the West. This practice has been termed “panda diplomacy“.[115] By 1984, however, pandas were no longer given as gifts. Instead, China began to offer pandas to other nations only on 10-year loans for a fee of up to US$1,000,000 per year and with the provision that any cubs born during the loan are the property of China. As a result of this change in policy, nearly all the pandas in the world are owned by China, and pandas leased to foreign zoos and all cubs are eventually returned to China.[116][117] As of 2022, Xin Xin at the Chapultepec Zoo in Mexico City, was the last living descendant of the gifted pandas.[118]

    Since 1998, because of a WWF lawsuit, the United States Fish and Wildlife Service only allows US zoos to import a panda if the zoo can ensure China channels more than half of its loan fee into conservation efforts for giant pandas and their habitat.[119][120] In May 2005, China offered a breeding pair to Taiwan. The issue became embroiled in cross-Strait relations – due to both the underlying symbolism and technical issues such as whether the transfer would be considered “domestic” or “international” or whether any true conservation purpose would be served by the exchange.[121] A contest in 2006 to name the pandas was held in the mainland, resulting in the politically charged names Tuan Tuan and Yuan Yuan (from simplified Chinese: 团圆; traditional Chinese: 團圓; pinyintuanyuanlit. ‘reunion’, implying reunification). China’s offer was initially rejected by Chen Shui-bian, then President of Taiwan. However, when Ma Ying-jeou assumed the presidency in 2008, the offer was accepted and the pandas arrived in December of that year.[122]

    In the 2020s, certain “celebrity pandas” have gained a cult following amongst internet users, with dedicated fan accounts existing to keep tabs on the animals. Known as “giant panda fever” or “panda-monium”, individual pandas are known to get billions of views and engagements on social media, as well as product lines specifically emulating them.[123] At Chengdu Research Base of Giant Panda Breeding, certain of these “celebrity pandas” are known to garner hours-long lines specifically to see them.[123][124]

    Conservation

    The giant panda is a vulnerable species, threatened by continued habitat loss and fragmentation,[31][125] and by a very low birthrate, both in the wild and in captivity.[48] Its range is confined to a small portion on the western edge of its historical range, which stretched through southern and eastern China, northern Myanmar, and northern Vietnam. The species is scattered into more than 30 subpopulations of relatively few animals. Building of roads and human settlement near panda habitat, result in population declines. Diseases from domesticated pets and livestock is another threat. By 2100, it is estimated that the distribution of giant pandas will shrink by up to 100%, mainly due to the effects of climate change.[1] The giant panda is listed on CITES Appendix I, meaning trade of their parts is prohibited and that they require this protection to avoid extinction.[126] They have been protected and placed in category 1, by the 1988 Wildlife Protection Act.[127]

    The giant panda has been a target of poaching by locals since ancient times and by foreigners since it was introduced to the West. Starting in the 1930s, foreigners were unable to poach giant pandas in China because of the Second Sino-Japanese War and the Chinese Civil War, but pandas remained a source of soft furs for the locals. The population boom in China after 1949 created stress on the pandas’ habitat and the subsequent famines led to the increased hunting of wildlife, including pandas. After the Chinese economic reform, demand for panda skins from Hong Kong and Japan led to illegal poaching for the black market, acts generally ignored by the local officials at the time. In 1963, the PRC government set up Wolong National Nature Reserve to save the declining panda population.[128]

    Close-up of a seven-month-old panda cub

    The giant panda is among the world’s most adored and protected rare animals, and is one of the few in the world whose natural inhabitant status was able to gain a UNESCO World Heritage Site designation. The Sichuan Giant Panda Sanctuaries, located in the southwest province of Sichuan and covering seven natural reserves, were inscribed onto the World Heritage List in 2006.[129][130][131] A 2015 paper found that the giant panda can serve as an umbrella species as the preservation of their habitat also helps other endemic species in China, including 70% of the country’s forest birds, 70% of mammals and 31% of amphibians.[132]

    In 2012, Earthwatch Institute, a global nonprofit that teams volunteers with scientists to conduct important environmental research, launched a program called “On the Trail of Giant Panda”. This program, based in the Wolong National Nature Reserve, allows volunteers to work up close with pandas cared for in captivity, and help them adapt to life in the wild, so that they may breed, and live longer and healthier lives.[133] Efforts to preserve the panda bear populations in China have come at the expense of other animals in the region, including snow leopards, wolves, and dholes.[134] In order to improve living and mating conditions for the fragmented populations of pandas, nearly 70 natural reserves have been combined to form the Giant Panda National Park in 2020. With a size of 10,500 square miles, the park is roughly three times as large as Yellowstone National Park and incorporates the Wolong National Nature Reserve. Small, isolated populations run the risk of inbreeding and smaller genetic variety makes the individuals more vulnerable to various defects and genetic mutation.[135]

    Population

    In 2006, scientists reported that the number of pandas living in the wild may have been underestimated at about 1,000. Previous population surveys had used conventional methods to estimate the size of the wild panda population, but using a new method that analyzes DNA from panda droppings, scientists believed the wild population were as large as 3,000.[48] In 2006, there were 40 panda reserves in China, compared to just 13 reserves in 1998.[136] As the species has been reclassified from “endangered” to “vulnerable” since 2016, the conservation efforts are thought to be working. Furthermore, in response to this reclassification, the State Forestry Administration of China announced that they would not accordingly lower the conservation level for panda, and would instead reinforce the conservation efforts.[137]

    In 2020, the panda population of the new national park was already above 1,800 individuals, which is roughly 80 percent of the entire panda population in China. Establishing the new protected area in the Sichuan Province also gives various other endangered or threatened species, like the Siberian tiger, the possibility to improve their living conditions by offering them a habitat.[138] Other species who benefit from the protection of their habitat include the snow leopard, the golden snub-nosed monkey, the red panda and the complex-toothed flying squirrel.[139]

    In July 2021, Chinese conservation authorities announced that giant pandas are no longer endangered in the wild following years of conservation efforts, with a population in the wild exceeding 1,800.[139][140] China has received international praise for its conservation of the species, which has also helped the country establish itself as a leader in endangered species conservation.[141]: 8