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Penguin

2007 Schools Wikipedia Selection. Related subjects: Birds

   iPenguins

                       Fossil range: Paleocene-Recent

   Chinstrap Penguin, Pygoscelis antarctica
   Chinstrap Penguin, Pygoscelis antarctica
               Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Aves
   Order:   Sphenisciformes
            Sharpe, 1891
   Family:  Spheniscidae
            Bonaparte, 1831

                                Modern Genera

     * Aptenodytes
     * Eudyptes
     * Eudyptula
     * Megadyptes
     * Pygoscelis
     * Spheniscus
     * For extinct genera, see Systematics

   Penguins (order Sphenisciformes, family Spheniscidae) are an order of
   aquatic, flightless birds living exclusively in the Southern
   Hemisphere.

Species and habitats

   The number of penguin species has been and still is a matter of debate.
   The numbers of penguin species listed in the literature varies between
   16 and 19 species. Some sources consider the White-Flippered Penguin a
   separate Eudyptula species, although today it is generally considered a
   subspecies of the Little Penguin (e.g. Williams, 1995; Davis & Renner,
   2003). Similarly, it is still unclear whether the Royal Penguin is
   merely a colour morph of the Macaroni penguin. Also possibly eligible
   to be treated as a separate species is the Northern population of
   Rockhopper penguins (Davis & Renner, 2003). Although all penguin
   species are native to the southern hemisphere, they are not, contrary
   to popular belief, found only in cold climates, such as Antarctica. In
   fact, only a few species of penguin actually live so far south. Three
   species live in the tropics; one lives as far north as the Galápagos
   Islands (the Galápagos Penguin).

   The largest living species is the Emperor Penguin (Aptenodytes
   forsteri): adults average about 1.1 m (3 ft 7 in) tall and weigh 35 kg
   (75 lb) or more. The smallest penguin species is the Little Blue
   Penguin (also known as the Fairy Penguin), which stands around 40 cm
   tall (16 in) and weighs 1 kg (2.2 lb). Generally larger penguins retain
   heat better, and thus inhabit colder regions, while smaller penguins
   are found in temperate or even tropical climates (see also Bergmann's
   Rule). Some prehistoric species attained enormous sizes, becoming as
   high as an adult human; see below for more.

   Most penguins feed on krill, fish, squid, and other forms of sealife
   caught while swimming underwater. They spend half of their life on land
   and half in the oceans.

   When 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.

   Penguins seem to have no fear of humans and have approached groups of
   explorers without hesitation. This is probably on account of there
   being no land predators in Antarctica or the nearby offshore islands
   that prey on or attack penguins. Instead, penguins are at risk at sea
   from such predators as the leopard seal.

Evolution

   The evolutionary history of penguins is poorly understood, as penguin
   fossils are rare. The oldest known fossil penguin species are the
   Waimanu, which lived in the early Paleocene epoch of New Zealand, about
   62 million years ago. While they were not as well adapted to aquatic
   life as modern penguins (which first emerged in the Eocene epoch 40
   million years ago), Waimanu were flightless and loon-like, with short
   wings adapted for deep diving. These fossils prove that prehistoric
   penguins were already flightless and seagoing, so their origins
   probably reach as far back as 65 million years ago, before the
   extinction of the dinosaurs. Penguin ancestry beyond Waimanu is not
   well known, though some scientists (Mayr, 2005) think the penguin-like
   plotopterids (usually considered relatives of anhingas and cormorants)
   may actually be an early sister group of the penguins, and that
   penguins may have ultimately shared a common ancestor with the
   Pelecaniformes.

   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 (6 feet) tall. The heaviest
   known species was with at least 80 kg the New Zealand Giant Penguin.
   Both were found on New Zealand, the former also in the Antarctic.

   Palaeeudyptines
   Traditionally, most extinct species of penguins, giant or small, have
   been placed in the paraphyletic sub-family called Palaeeudyptinae. More
   recently, it is becoming accepted that there were at least 2 major
   extinct lineages, one or two closely related ones from Patagonia and at
   least one other with pan- Antarctic and subantarctic distribution. For
   a complete list of these generarations, see below.

Systematics

   (updated after Marples, 1962, and Acosta Hospitaleche, 2004)

   ORDER SPHENISCIFORMES
     * Waimanu
     * Family Spheniscidae
          + Subfamily Palaeeudyptinae (Giant penguins, fossil)
               o Palaeeudyptes
               o Archaeospheniscus
               o Anthropornis
                    # Nordenskjoeld's Giant Penguin, Anthropornis
                      nordenskjoeldi
               o Crossvallia (tentatively assigned to this subfamily)
               o Delphinornis
               o Pachydyptes
               o Platydyptes
               o Anthropodyptes (tentatively assigned to this subfamily)
          + Subfamily Paraptenodytinae (Patagonian stout-legged penguins,
            fossil)
               o Paraptenodytes
               o Arthrodytes
          + Subfamily Palaeospheniscinae (Patagonian slender-legged
            penguins, fossil)
               o Palaeospheniscus - includes Chubutodyptes
          + Subfamily Spheniscinae (modern penguins)
               o Aptenodytes
                    # King Penguin, Aptenodytes patagonicus
                    # Emperor Penguin, Aptenodytes forsteri
                    # Ridgen's Penguin, Aptenodytes ridgeni (fossil)
               o Pygoscelis
                    # Gentoo Penguin, Pygoscelis papua
                    # Tyree's Penguin, Pygoscelis tyreei (fossil)
                    # Adelie Penguin, Pygoscelis adeliae
                    # Chinstrap Penguin, Pygoscelis antarctica
                    # Pygoscelis grandis (fossil)
                    #  ?Pygoscelis small sp. (fossil, may be different
                      genus)
               o Eudyptes
                    # Rockhopper Penguin, Eudyptes chrysocome
                    # Fiordland Penguin, Eudyptes pachyrhynchus
                    # Snares Penguin, Eudyptes robustus
                    # Royal Penguin, Eudyptes schlegeli
                    # Erect-crested Penguin, Eudyptes sclateri
                    # Macaroni Penguin, Eudyptes chrysolophus
                    # Chatham Islands Penguin, Eudyptes sp. (
                      prehistoric?)
               o Megadyptes
                    # Yellow-eyed Penguin, Megadyptes antipodes
               o Eudyptula
                    # Little Penguin (Blue or Fairy Penguin), Eudyptula
                      minor
                    # White-Flippered Penguin, Eudyptula albosignata
               o Spheniscus
                    # Spheniscus predemersus (fossil)
                    # African Penguin (Jackass or Blackfooted Penguin),
                      Spheniscus demersus
                    # Spheniscus chilensis (fossil)
                    # Spheniscus megaramphus (fossil)
                    # Spheniscus urbinai (fossil)
                    # Magellanic Penguin, Spheniscus magellanicus
                    # Humboldt Penguin, Spheniscus humboldti
                    # Galápagos Penguin, Spheniscus mendiculus

     *
          + Not assigned to a subfamily (all fossil)
               o Dege
               o Duntroonornis
               o Eretiscus
               o Insuza
               o Korora
               o Marplesornis
               o Marambiornis
               o Mesetaornis
               o Nucleornis
               o Pseudaptenodytes
               o Tonniornis
               o Wimanornis

Anatomy

   Penguins are superbly adapted to an aquatic life. Their wings have
   become flippers, useless for flight in the air. In the water, however,
   penguins are astonishingly agile. 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 - that is, they have a white underside
   and a dark (mostly black) upperside. This is for camouflage. 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.

   Diving penguins reach 6 to 12 km/h (3.7 to 7.5 mph), though there are
   reports of velocities of 27 km/h (17 mph) (which are more realistic in
   the case of startled flight). 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. Dives of the large Emperor Penguin have been recorded which reach
   a depth of 565 m (1870 ft) and last up to 20 minutes.

   Penguins either waddle on their feet or slide on their bellies across
   the snow, a movement called "tobogganing", which allows them to
   conserve energy and move relatively fast at the same time.

   Penguins have an excellent sense of hearing. Their eyes are adapted for
   underwater vision, and are their primary means of locating prey and
   avoiding predators; in air, conversely, they are nearsighted. Their
   sense of smell has not been researched so far.

   They are able to drink salt water safely because their supraorbital
   gland filters excess salt from the bloodstream. The salt is excreted in
   a concentrated fluid from the nasal passages.

Mating habits

   Some penguins mate for life, while others for just one season. They
   generally raise a small brood, and the parents cooperate in caring for
   the clutch and for the young. During the cold season on the other hand
   the mates separate for several months to protect the egg. The male
   stays with the egg and keeps it warm, and the female goes out to sea
   and finds food so that when it comes home, the baby will have food to
   eat. Once the female comes back, they switch.

Male bonding behaviour

   In early February 2004 the New York Times reported a male pair of
   Chinstrap penguins in the Central Park Zoo in New York City were
   partnered, and when given an egg which needed incubation, successfully
   hatched it. Other penguins in New York have also been reported to be
   forming same-sex pairs.

   This was the basis for the children's picture book And Tango Makes
   Three. The couple about whom the book was based, Roy and Silo, would
   see further interesting developments in their relationship when in
   September 2005, Silo left Roy for a female penguin.

   Zoos in Japan and Germany have also documented male penguin couples.
   The couples have been shown to build nests together and use a stone to
   replace an egg in the nest. Researchers at Rikkyo University in Tokyo,
   found twenty such pairs at sixteen major aquariums and zoos in Japan.
   Bremerhaven Zoo in Germany attempted to break up the male couples by
   importing female penguins from Sweden and separating the male couples;
   they were unsuccessful. The zoo director stated the relationships were
   too strong between the older couples.

Name

   Penguin is thought by some to derive from the Welsh words pen (head)
   and gwyn (white), applied to the Great Auk, which had a conspicuous
   white patch between the bill and the eye (although its head was black),
   or from an island off Newfoundland known as "White Head" due to a large
   white rock. This may be, however, a false etymology created by Dr. John
   Dee in his book on Prince Madoc of Wales, supposedly one of the
   discoverers of America. By this Dee hoped to cement Queen Elizabeth I's
   claim, as a Tudor, to the New World. Penguins live nowhere near
   Newfoundland, nor do they generally have white heads, however Great
   Auks did look remarkably like penguins. According to another theory,
   the original name was pen-wing, with reference to the rudimentary wings
   of both Great Auks and penguins. A third theory is that penguin comes
   from the Latin pinguis (fat). This has added credibility because in two
   other Germanic languages, Dutch 'pinguïn' and German, 'Pinguin' both
   have the 'i' vowel too. While it has been replaced by an 'e' in the
   English spelling, it can still be heard. By simply looking at the
   word's pronunciation and comparing that to the Dutch and German words,
   one could assume a common Latin root - after the first Germanic sound
   shift (500-200 BC) that makes a PIE 'p' into a 'f', of course. However,
   a Welsh 'i' is often mutated to an 'e' in the English language so the
   Welsh origin is still arguable..

Penguins in popular culture

   Tux the Linux mascot
   Enlarge
   Tux the Linux mascot

   Penguins are popular around the world primarily for their unusually
   upright, waddling pace and (compared to other birds) lack of fear
   towards humans. Their striking black and white plumage is often likened
   to a tuxedo suit and generates humorous remarks about the bird being
   "well dressed".

   Perhaps in reaction to this cutesy stereotype, fictional penguins are
   occasionally presented as grouchy or even sinister. The popular Sanrio
   character Badtz Maru is an example, being cute yet somewhat surly.

   The documentary March of the Penguins (2005) details a year in the life
   of a colony of Emperor Penguins mating, giving birth, and hunting for
   food in the harsh continent of Antarctica. It won the 2005 Academy
   Award for Documentary Feature.

   More recently, the animated film Happy Feet applies a musical treatment
   and a modified version of the ugly duckling fable to the lifecycle of
   the Emperor Penguins, with an additional plotline about the impact of
   human fishing activities on penguin (and other arctic animal) food
   sources. The fable theme plays against the high visual similarity of
   penguins of the same species to one another (at least from a human
   perspective) in emphasizing how one individual may stand out from the
   crowd.

Penguins and polar bears

   Despite what commercials and other sources may show, the likelihood of
   a meeting between a penguin and a polar bear without human intervention
   is vanishingly small. This is because the two species are found on
   opposite hemispheres. Polar bears inhabit the northern hemisphere,
   while penguins mainly inhabit the southern hemisphere. This is a
   misconception that is fueled by popular culture such as movies and
   television. A prominent example of this takes place in a holiday 2005
   ad campaign by Coca-Cola featuring the partying penguins and the polar
   bears watching from afar.

Gallery

   Adelie penguin in Antarctica

   African Penguin

   Chinstrap Penguin hunting for krill

   Humboldt Penguin at the Milwaukee County Zoological Gardens

   Magellanic Penguin

   Gentoo Penguin

   Little Penguin - also called "Fairy Penguin"

   Emperor Penguins

   Gentoo Penguin at polish Arctowski base

   Retrieved from " http://en.wikipedia.org/wiki/Penguin"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
