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Tasmanian Devil

2007 Schools Wikipedia Selection. Related subjects: Mammals

                 iTasmanian Devil
   A male Tasmanian Devil.
   A male Tasmanian Devil.

                             Conservation status

   See text
            Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Class:      Mammalia
   Infraclass: Marsupialia
   Order:      Dasyuromorphia
   Family:     Dasyuridae
   Subfamily:  Dasyurinae
   Tribe:      Dasyurini
   Genus:      Sarcophilus
               F.G. Cuvier, 1837
   Species:    S. harrisii

                                Binomial name

   Sarcophilus harrisii
   ( Boitard, 1841)

   The Tasmanian Devil (Sarcophilus harrisii), also referred to simply as
   'the devil', is a carnivorous marsupial now found only in the
   Australian island state of Tasmania. The Tasmanian Devil is the only
   extant member of the genus Sarcophilus. The size of a small dog, but
   stocky and muscular, the Tasmanian Devil is the largest carnivorous
   marsupial in the world. It is characterised by its black fur, offensive
   odour when stressed, extremely loud and disturbing screech, and
   viciousness when feeding. It is known to both hunt prey and scavenge
   carrion and although it is usually solitary, it sometimes eats with
   other devils.

   The Tasmanian Devil became extirpated on the Australian mainland about
   400 years before European settlement in 1788. Because they were seen as
   a threat to livestock in Tasmania, devils were hunted until 1941, when
   they became officially protected. Since the late 1990s devil facial
   tumour disease has reduced the devil population significantly and now
   threatens the survival of the species, which may soon be listed as
   endangered. Programs are currently being undertaken by the Tasmanian
   government to reduce the impact of the disease.

Taxonomy

   Naturalist George Harris wrote the first published description of the
   Tasmanian Devil in 1807, naming it Didelphis ursina. In 1838 the devil
   was renamed Dasyurus laniarius by Richard Owen, before being moved to
   the genus Sarcophilus in 1841 and named Sarcophilus harrisii, or
   "Harris's meat-lover", by Pierre Boitard. A later revision of the
   devil's taxonomy, published in 1987, has changed the species name to
   Sarcophilus laniarius. The name S. harrisii has been retained and S.
   laniarius relegated to fossil species. Phylogenetic analysis shows that
   the devil is most closely related to quolls, and more distantly to the
   extinct Thylacine (Tasmanian Tiger).

Physical description

   The Tasmanian Devil is the largest surviving carnivorous marsupial in
   Australia. It has a squat and thick build, with a large head and a
   short, stubby tail. The devil stores body fat in its tail; an unhealthy
   devil often has a thin tail. Unusually for a marsupial, its forelegs
   are slightly longer than its hind legs. Devils can run in bursts at the
   impressive speed of 13 kilometres per hour (8.1 miles per hour). The
   fur is usually black, although irregular white patches on the chest and
   rump are common. Males are usually larger than females, having an
   average head and body length of 652 mm, with a 258 mm tail, and an
   average weight of 8 kg. Females have an average head and body length of
   570 mm, with a 244 mm tail, and an average weight of 6 kg. The average
   life expectancy of a Tasmanian Devil in the wild is estimated at six
   years, although it may live longer in captivity.

   The devil has long whiskers on its face and in clumps on the top of the
   head. These help the devil locate prey when foraging in the dark, and
   aid in detecting the closeness of other devils during feeding. When
   agitated, the devil can produce a strong odour, its pungency rivalling
   even the skunk. Hearing is its dominant sense, and it also has an
   excellent sense of smell. Since devils hunt at night, their vision
   seems to be strongest in black and white. In these conditions they can
   detect moving objects readily, but have difficulty seeing stationary
   objects. An analysis of mammalian bite force, corrected for body size,
   shows that the devil has the strongest bite of any living mammal. The
   power of the jaw is in part due to its comparatively large head. A
   Tasmanian Devil also has one set of teeth that grows slowly throughout
   its life.

Reproduction

   Developmental steps in the maturation of Tasmanian Devil young. The
   diagonal lines indicate the amount of time the changes take; for
   example, it takes 41 days for a devil to develop fur over all its body.
   Enlarge
   Developmental steps in the maturation of Tasmanian Devil young. The
   diagonal lines indicate the amount of time the changes take; for
   example, it takes 41 days for a devil to develop fur over all its body.

   Females start to breed when they reach sexual maturity, typically in
   their second year. At this point, they become fertile once a year,
   producing multiple ova while in heat. Mating occurs in March, in
   sheltered locations during both day and night. Males fight over females
   in the breeding season, and female devils will mate with the dominant
   male. Devils are not monogamous, and females will mate with several
   males if not guarded after mating. Gestation lasts 31 days, and devils
   give birth to 20–30 young, each weighing approximately 0.18–0.24 grams.
   When the young are born, they move from the vagina to the pouch. Once
   inside the pouch, they each remain attached to a nipple for the next
   100 days. The female Tasmanian Devil's pouch, like that of the wombat,
   opens to the rear, so it is physically difficult for the female to
   interact with young inside the pouch. Despite the large litter at
   birth, the female has only four nipples, so that no more than four
   young can survive birth. On average, more females survive than males.
   Those who do not procure a nipple are typically eaten by the mother.

   Inside the pouch, the nourished young develop quickly. At 15 days the
   external parts of the ear are visible. Eyelids are apparent at 16 days,
   whiskers at 17 days, and the lips at 20 days. The young start to grow
   fur at 49 days and have a full coat by 90 days. Their eyes open shortly
   after their fur coat develops—between 87 and 93 days—and their mouths
   can relax their hold of the nipple at 100 days. They leave the pouch
   105 days after birth, appearing as small copies of the parent and
   weighing approximately 200 grams. Unlike kangaroo joeys, young devils
   do not return to the pouch; instead, they remain in the den for another
   three months, first venturing outside the den between October and
   December before becoming independent in January. Female devils are
   occupied with raising their young for all but approximately six weeks
   of the year.

Ecology and behaviour

   Although Tasmanian Devils are nocturnal, they like to rest in the sun.
   Scarring from fighting is visible next to this devil's left eye.
   Enlarge
   Although Tasmanian Devils are nocturnal, they like to rest in the sun.
   Scarring from fighting is visible next to this devil's left eye.

   Tasmanian Devils are widespread and fairly common throughout Tasmania.
   Found in all habitats on the island, including the outskirts of urban
   areas, they particularly like dry sclerophyll forests and coastal
   woodlands. The Tasmanian Devil is a nocturnal and crepuscular hunter,
   spending the days in dense bush or in a hole. Young devils can climb
   trees, but this becomes more difficult as they grow larger. Devils can
   also swim. They are predominantly solitary animals and do not form
   packs. They occupy territories of 8–20 km², which can overlap
   considerably amongst different animals.
   A devil eating a wallaby killed by a car earlier that day
   Enlarge
   A devil eating a wallaby killed by a car earlier that day

   Tasmanian Devils can take prey up to the size of a small wallaby, but
   in practice they are opportunistic and eat carrion more often than they
   hunt live prey. Although the devil favours wombats, it will eat all
   small native mammals, domestic mammals (including sheep), birds, fish,
   insects, frogs and reptiles. Their diet is largely varied and depends
   on the food available. On average, they eat about 15% of their body
   weight each day; however, they can eat up to 40% of their body weight
   in 30 minutes if the opportunity arises. Tasmanian Devils eliminate all
   traces of a carcass, devouring the bones and fur in addition to the
   meat and internal organs. In this respect, the devil has earned the
   gratitude of Tasmanian farmers, as the speed at which they clean a
   carcass helps prevent the spread of insects that might otherwise harm
   livestock.

   Eating is a social event for the Tasmanian Devil, and much of the noise
   attributed to the animal is a result of raucous communal eating, at
   which up to 12 individuals can gather and which can often be heard
   several kilometers away. A study of feeding devils identified 20
   physical postures, including their characteristic vicious yawn, and 11
   different vocal sounds that devils use to communicate as they feed.
   They usually establish dominance by sound and physical posturing,
   although fighting does occur. Adult males are the most aggressive, and
   scarring is common from fighting over food and mates.

Conservation status

   For some time, Tasmania was the last refuge of large marsupial
   carnivores. All of the larger carnivorous marsupials became extinct in
   mainland Australia shortly after humans arrived. Only the smallest and
   most adaptable survived. Fossil evidence from western Victoria shows
   that Tasmanian Devils retained a place on the Australian mainland until
   around 600 years ago (about 400 years before European colonisation).
   Their extinction is attributed to predation by dingoes and hunting by
   indigenous Australians. In dingo-free Tasmania, carnivorous marsupials
   were still active when Europeans arrived. The extermination of the
   Thylacine after the arrival of the Europeans is well known, but the
   Tasmanian Devil was threatened as well.

   The first Tasmanian settlers ate Tasmanian Devil, which they described
   as tasting like veal. As it was believed devils would hunt and kill
   livestock, a bounty scheme to remove the devil from rural properties
   was introduced as early as 1830. Over the next 100 years, trapping and
   poisoning brought them to the brink of extinction. After the death of
   the last Thylacine in 1936, the threat to the devils was recognized.
   The Tasmanian Devil was protected by law in 1941, and the population
   slowly recovered.

   At least two major population declines, possibly due to a disease
   epidemic, have occurred in recorded history: in 1909 and 1950. The
   Tasmanian Devil's current population is thought to be in the range of
   100,000 to 150,000, a density of approximately 20 devils per 10–20 km^2
   area. Tasmania and Australia prohibit the export of Tasmanian Devils.

Devil facial tumour disease

   First seen in 1996, devil facial tumour disease (DFTD) has ravaged
   Tasmania's wild devils, and estimates of the impact range from 20% to
   as much as a 50% decline in the devil population with over 65% of the
   State affected. Affected high-density populations suffer up to 100%
   mortality in 12–18 months. The species was listed as vulnerable under
   the Tasmanian Threatened Species Protection Act 1995 and the Australian
   Environment Protection and Biodiversity Conservation Act 1999 in 2006
   which means that it is at risk of extinction in the "medium term". The
   IUCN does not regard the species as threatened; when this species was
   last evaluated for the IUCN is 1996, it was listed as lower risk/least
   concern.

   Wild Tasmanian Devil populations are being monitored to track the
   spread of the disease and to identify changes in disease prevalence.
   Field monitoring involves trapping devils within a defined area to
   check for the presence of the disease and determine the number of
   affected animals. The same area is visited repeatedly to characterise
   the spread of the disease over time. So far, it has been established
   that the short-term effects of the disease in an area can be severe.
   Long-term monitoring at replicated sites will be essential to assess
   whether these effects remain, or whether populations can recover. Field
   workers are also testing the effectiveness of disease suppression by
   trapping and removing diseased devils. It is hoped that the removal of
   diseased devils from wild populations should decrease disease
   prevalence and allow more devils to survive beyond their juvenile years
   and breed.

   Two 'insurance' populations of disease-free devils are being
   established at an urban facility in the Hobart suburb of Taroona and on
   Maria Island off the east coast of Tasmania. Captive breeding in
   mainland zoos is also a possibility. The decline in devil numbers is
   also seen as an ecological problem, since its presence in the Tasmanian
   forest ecosystem is believed to have prevented the establishment of the
   Red Fox, illegally introduced to Tasmania in 2001. Foxes are a
   problematic invasive species in all other Australian States, and the
   establishment of foxes in Tasmania would hinder the recovery of the
   Tasmanian Devil.
   Retrieved from " http://en.wikipedia.org/wiki/Tasmanian_Devil"
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   with only minor checks and changes (see www.wikipedia.org for details
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