Tasmanian devil
| Tasmanian devil | ||||||||||||
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Tasmanian devil ( Sarcophilus harrisii ) |
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| Systematics | ||||||||||||
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| Sarcophilus | ||||||||||||
| F. Cuvier , 1837 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Sarcophilus harrisii | ||||||||||||
| Boitard , 1841 |
The Tasmanian Devil ( Sarcophilus harrisii ), and Tasmanian Devil called, is a species from the family of dasyuridae (Dasyuridce) and its greatest living representative. Today it can only be found in Tasmania , on the Australian mainland it was probably already extinct in the 14th century. For the hoped-for protection of the livestock, it was hunted intensively in Tasmania until the 1930s. Since the Tasmanian devil was placed under protection in 1941, the population has recovered. However, the species has been threatened by Devil Facial Tumor Disease (DFTD) since the late 1990s .
Names
The marsupial got its name because of its black fur, its ears that turn red when excited, its very unpleasant body odor, especially when excited, its loud screeching that can be heard from very long distances, and its aggressive and curious behavior towards you defeated prey and everything that it encounters.
Its scientific name has changed several times over the past two hundred years. The natural scientist George Harris described the marsupial devil in 1808 and gave it the scientific name Didelphis ursina . However, this name had already been given to another animal in 1800, the naked-nosed wombat (today Vombatus ursinus ) and is therefore invalid. In 1837 Frédéric Cuvier introduced the new genus Sarcophilus , but still with the invalid specific epithet ursinus . In 1838, Richard Owen described fossil material that was very similar to the Tasmanian devil as Dasyurus laniarius . In 1841 Pierre Boitard named the living species Sarcophilus harrisii . Subsequently, it was long disputed whether the extinct species S. laniarius would be identical to the living S. harrisii or not - if they were identical, S. laniarius would be the valid name of the Tasmanian devil. More recently, there have been increasing voices who consider the fossil record to be a species of its own and therefore consider Sarcophilus harrisii to be a valid scientific name for the marsupial.
The latest phylogenetic investigations show that the marsupial devils are closely related to the sacred martens , as they are classified into the predator family. On the other hand, there is only a distant relationship to the extinct thylacine .
features
The marsupial devil is the largest living predator. The males have an average head body length of 65 centimeters, the tail has an average length of almost 26 centimeters and they weigh about eight kilograms. Females are slightly smaller and lighter: their head body length averages 57 centimeters, their tail is 24 centimeters long, and they weigh about six kilograms.
The physique of the Tasmanian devil is compact and strong. The front legs are slightly longer than the back legs. The head is short and broad, the teeth are very strong and ideal for breaking bones. The fur is black or dark brown, with the exception of a white strip of throat and occasional white spots on the trunk. Tasmanian devils store body fat in their tails. A sick marsupial devil can therefore usually be recognized by a thin tail. When aroused, the marsupial devil gives off a pungent odor that is as unpleasant as that of the skunk . Hearing and smell are very good, but he can see relatively poorly.
A study of the bite force in relation to body size has shown that the Tasmanian devil has the strongest bite of any mammal . It is above all the large head in relation to his body size that makes his jaws so powerful.
distribution
Tasmanian devils now only live in Tasmania , which is why they are sometimes referred to as Tasmanian devils or Tasmanian devils .
Based on fossil finds , it is assumed that the Tasmanian devil did not become extinct on the Australian continent until the 14th century. Its extinction is attributed to competition from dingoes and hunting by Aborigines . Tasmanian devils have survived - like some other predatory baggers - on the thing-free island of Tasmania. The species has also survived the persecution by Europeans there, which has led to the extinction of other predatory baggers such as the thylacine . In the Pleistocene , another species of marsupial ( Sarcophilus laniarius ) occurred in Australia, which was about 25% larger than today's marsupial ( Sarcophilus harrisii ).
Habitat and way of life
Tasmanian devils can be found all over Tasmania and can be considered relatively common. They use almost all habitats on the island and are also found in the outskirts of cities . However, their preferred living quarters are dry forests and the wooded areas along the coast . They prefer to hunt during the night and at dusk and spend the day either in thick bushes or in an underground burrow. Tasmanian devils can swim. Young marsupial devils can also climb trees; as they get older, this becomes more and more difficult for the animals.
Apart from the mating season, they are loners. The action spaces they use are between eight and twenty square kilometers. The action areas of several animals can overlap considerably.
Food and subsistence
Tasmanian devils are able to kill animals up to the size of a small wallaby , but most of their prey is dying animals or carrion . Their food spectrum includes smaller mammals , preferably wombats , as well as birds , insects , frogs and reptiles , but also domestic animals such as sheep .
The diet of the Tasmanian devil is thus variable and depends on which food sources are available to him. On average, he consumes around 15 percent of his body weight in food per meal. If given the opportunity, however, he is also able to eat amounts within 30 minutes that correspond to around 40 percent of his body weight.
Tasmanian devils devour their prey completely - that is, in addition to the meat and internal organs, they also consume the bones and fur of a prey. Some Tasmanian farmers therefore value Tasmanian devils for their ecological role. The speed with which they clear carcasses prevents insects from multiplying, which could otherwise adversely affect the rest of the livestock.
Although the marsupial devil is a solitary creature, several can appear around a large carcass. Tasmanian devils fight fiercely with each other and the screeching sounds they utter during these rough communal meals can be heard over several kilometers. Studies of the feeding behavior of the Tasmanian devil have shown that twenty different postures can be identified. The characteristic aggressive, threatening yawn is also one of the typical behavioral features. Eleven different vocalizations can be made out. The ranking among the animals is usually determined by utterances and threatening postures. However, fights are also very common. Adult males are usually more aggressive and almost always have scars that they get when fighting for food and sexual partners.
Reproduction
Female marsupial devils are sexually mature in their second year of life and from then on they begin to reproduce.
Mating mostly takes place in March. The males fight for the females in heat , who can be mated by the dominant male. For pairing occurs both at night and during the day. Tasmanian devils are not monogamous and a female can be mated by several males unless her last sexual partner actively prevents this.
The development of the embryos takes 31 days. Female marsupials give birth to between twenty and thirty completely naked and limited mobility cubs. Each young animal weighs only between 0.18 and 0.24 grams. Immediately after birth, they crawl from the vagina to the pouch of the mother that is open to the rear. If they are in the bag, they attach to one of the mammary glands, where they remain for the next 100 days. Despite the large number of young that a female marsupial devil usually has, it only has four mammary glands, so that a litter can grow to a maximum of four young. On average, more females than males manage to attach themselves to one of the mammary glands. The kittens in a litter that fail to find a mammary gland are usually eaten by their mother.
Similar to the wombat , the mother cannot interact with the young because the pouch is open to the rear. The young in the pouch develop very quickly. From the 15th day the ears become visible, eyelids are visible on the 16th day and the whiskers appear on the 17th day. The lips can be seen on the 20th day. The young animals develop their fur at 49 days. The fur development is completed on the 90th day of life. Their eyes open between the 87th and 93rd day of life and around the 100th day of life they loosen their hold on the mammary gland. An average of 105 days after they have made their way from the vagina to the pouch, the 200 gram pups leave it. Unlike kangaroos , young devils do not return to the pouch. For the next three months they will remain in the mother's den. They leave this for the first time between October and December. In January they will be completely independent. Except for the six weeks between when their offspring become independent and when they mate again in March, female marsupial devils are almost exclusively engaged in reproductive activities.
Duration
Population development after Tasmania was settled by European settlers
Europeans settled Australia from 1788 and soon settled in Tasmania. Similar to the Aborigines, they also ate marsupial devils, the taste of which they compared to that of calves. Since the European settlers were convinced that marsupial devils represented a threat to their livestock, a bonus system was established as early as 1830, which rewarded the shooting of marsupial devils. Over the next hundred years, trapping and poisoning operations reduced the number of marsupial devils so much that they were on the verge of extinction. The fact that the last Tasmanian tiger died in 1936 contributed to their protection . Tasmanian devils have been under protection since 1941 and their numbers have recovered.
Current inventory
In addition to hunting, at least two disease epidemics have significantly reduced the numbers of Tasmanian devils. The first took place in 1909 and the second in 1950. For 1999, 100,000 to 150,000 individuals were assumed, which means that every 20 Tasmanian devils colonize an area of ten to 20 square kilometers each. Tasmania and Australia regulate the export of marsupial devils very strictly and so currently live in Copenhagen Zoo , in some US zoos, such as B. since 2013 in the San Diego Zoo , and since the end of March 2017 in the Duisburg Zoo, Tasmanian devil outside Australia.
Recently, however, another epidemic has led to a drastic decline in the population. It is a cancer that mainly affects parts of the face.
The DFTD threat
The outbreak of DFTD
The disease that afflicts Tasmanian devils is called Devil Facial Tumor Disease (DFTD), which can be translated as facial cancer typical of the Tasmanian devil . The causative agent of Devil Facial Tumor Disease is an infectious tumor . The common English abbreviation DFTD is used for this in the following.
DFTD was first detected in Northeast Tasmania in 1996. Since then, the disease has been rampant among the Tasmanian devil population. Up to 2005, half of the area where the Tasmanian devil is spread was affected and the population collapse is estimated at up to 85 percent. In regions densely populated with marsupial devils, all marsupial devils died within a period of twelve to eighteen months. So far, the outbreak of the disease has been concentrated in eastern Tasmania. In early 2005, however, three cases were reported in the south of the island. If DFTD continues to spread at this rate, it could cause the Tasmanian devil to become extinct within the next 20 to 30 years.
According to recent findings, the cause of the rapid spread of the disease is the low genetic diversity in the total population of the Tasmanian devil and thus the lack of variable immune reactions. According to research by Australian scientists, measures that should actually lead to containment of the disease were counterproductive and favored an evolution of the disease due to the presence of two different tumor strains.
Course of disease
The first symptoms of DFTD are swellings and lumps around the mouth . These nodes develop into tumors that spread from the head and across the body. The tumors prevent the animals from eating and the affected animals eventually starve to death because they are no longer able to take in food.
Studies on infected tissue have shown that the cancer has neuroendocrine ( hormone- producing) properties and that identical chromosome changes can be found in all cancer cells.
Initially, it was believed that a virus was the cause of DFTD. However, no viruses could be detected in the cancer cells. It is currently being investigated whether the cancer cells are directly responsible for the transmission. Since the marsupial devils occasionally fight fiercely for food and bite each other, it is assumed that the cancer cells spread through the saliva of the conspecifics. In fact, they resemble a canine cancer of the genitals known as sticker sarcoma , which is spread through body contact.
A main problem of the disease is that the MHC proteins of the tumor cells hardly differ from those of healthy cells, which is why the immune system of the animals does not recognize and fight them as tumor cells. Scientists from the University of Sydney reported in February 2010 the discovery of an MHC gene group in a population of healthy marsupial devils, in which clear differences compared to the otherwise usual MHC gene group were found. The researchers hope that this genetic variability will cause resistance to DFTD.
In March 2013, researchers at Cambridge University found a starting point for a vaccine: “If you treat tumor cells with interferon and then inject them into the Tasmanian devils in a deactivated form, their immune system recognizes them as foreign - and remembers them next to the 'label' of the MHC -Complex also other tell-tale proteins on the cell surface. If unmanipulated DFTD cells then get into the bag's body through a bite, the defense has a chance to recognize and fight them despite the lack of an MHC label on these proteins. The nice thing about it: Once this happens, the immune system produces interferon gamma by itself and thus also forces the newly invaded tumor cells to give themselves away, as the researchers report. Further tests and research are still necessary, but the new findings could open up a possibility for the first time to protect the last big predator on our planet from the ultimate end. "
Countermeasures
Tasmanian devil populations are currently being closely monitored to determine the spread of the disease and changes in the clinical picture. Among the scientific studies repeatedly capture part of all Tasmanian Devil in a marked out area. This is to help determine how the disease is spreading over time. What is certain is that the disease can kill all animals in an area. The observation periods are still too short to say whether these regions will be repopulated by other marsupial devils. It is also being tested whether catching and removing sick animals can slow the spread of the disease.
Great hope was placed in the so-called culling , i.e. the precautionary killing of infected or even all animals of an affected population. However, recent research shows that this method is not an appropriate measure to prevent the spread of the disease.
In the north of Tasmania there are two wildlife parks, Trowunna Wildlife Park and Devils at Cradle Wildlife Park , which are dedicated to the rearing of healthy animals and which have already achieved a number of successes with reintroduction in some places (Maria Island, Peninsula Devil Conservation Project and Wild Devil Recovery in Narawntapu). This is done as part of the Tasmanian Devil Rescue Program , Save the Tasmanian Devil Program (STDP), which is under the care of the Tasmanian and Australian governments.
The Tasmanian Peninsula is home to the Tasmanian Devil Conservation Park , which is home to an isolated population, and since the peninsula is only connected to the mainland by a land bridge, there is a good chance these animals will not become infected.
The breeding programs of zoos located on mainland Australia could also prevent this species from becoming extinct if the wild population collapses due to DFTD.
Red fox and marsupial devil
The decline in the numbers of Tasmanian devils is also of concern for another reason. Unlike Australia , Tasmania was free of red foxes until the turn of the millennium . Red foxes have been shown to be aggressive invasive neozoa in Australia , the presence of which can have a dramatic impact on native wildlife.
In 2001 the red fox was illegally released in Tasmania. The fact that, unlike in Australia, it was not immediately able to establish itself in this new habitat was attributed, among other things, to the presence of the aggressive marsupial devils. However, it cannot be ruled out that marsupial devils will find it difficult to re-establish themselves in a territory once foxes have conquered a territory free of marsupial devils.
Tasmanian devil and human
The Tasmanian devil is the symbol of the Tasmanian National Park and Wildlife Services and the Tasmanian football team is called The Devils, based on this animal . The Tasmanian devil is also one of six animals native to Australia and Tasmania featured on the two hundred dollar coins issued between 1989 and 1994.
Tasmanian devils have been the subject of documentaries and non-fiction books for children on several occasions because of their way of life. An Australian documentary called Terror of Tasmania was released by David Parer and Elizabeth Parer-Cook in 2005. The documentary follows a female marsupial named Manganinnie through the mating season, the birth and the rearing of the young, and also deals with the effects of DFTD and the protective measures that are intended to ensure the continued existence of the species. The documentary appeared on the National Geographic Channel in both North America and Australia. The two German animal filmmakers Hans Schweiger and Ernst Arendt ( animals in front of the camera ) also made a film about the Tasmanian devil.
The restrictions on the export of marsupial devils mean that, with a few exceptions, marsupial devils can currently only be seen in captivity in Australia and Tasmania. The Tasmanian government gave four animals to Copenhagen Zoo as a present for the birth of the Danish Prince Christian, as Christian’s mother, Princess Mary , comes from Tasmania. Offspring of these animals can be seen in the zoos of Mechelen, Brugelette and Duisburg. The previously last living outside of Australia Tasmanian devils died in 2004 at the zoo in Fort Wayne in the US state of Indiana , also to DFTD.
Probably the most famous marsupial devil is the character of the Tasmanian devil Taz in the animated series Looney Tunes . The only similarity between the cartoon character and the actual Tasmanian devil, however, is their appetite.
Tasmanian devils do not usually attack humans, but when attacked or caught they will defend themselves with powerful bites and can pose a threat to young children.
The mascot Tux the Linux -Project was in the kernel version 2.6.29 for 3 months by 2009 Tuz replaced, a Tasmanian devil with attached yellow Pappschnabel. Linus Torvalds wanted to draw attention to the situation of the bag devil.
literature
- Diana O. Fisher, Ian PF Owens, Christopher N. Johnson: The ecological basis of life history variation in marsupials. In: Ecology. Vol. 82, 2001, pp. 3531-3540, doi : 10.2307 / 2680170 .
- Colin Groves : Antechinus subtropicus. In: Don E. Wilson , DeeAnn M. Reeder (Eds.): Mammal Species of the World . A Taxonomic and Geographic Reference. Volume 1. 3rd edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-801-88221-4 .
- Robert K. Rose, David A. Pemberton, Nick J. Mooney, Menna E. Jones: Sarcophilus harrisii (Dasyuromorphia: Dasyuridae). Mammalian Species 49 (942), May 1, 2017; Pp. 1-17. doi : 10.1093 / mspecies / sex001
- Eric R. Guiler: Observations on the Tasmanian Devil, Sarcophilus harrisii (Marsupialia: Dasyuridae). II. Reproduction, Breeding and Growth of Pouch Young. In: Australian Journal of Zoology. Vol. 18, 1970, ISSN 0004-959X , pp. 63-70.
- George P. Harris: Description of two species of Didelphis for Van Diemen's Land. In: The Transactions of the Linnean Society of London. Vol. 9, 1808, pp. 174-178 .
- Christopher N. Johnson, Stephen Wroe: Causes of extinction of vertebrates during the Holocene of mainland Australia, arrival of the dingo, or human impact? In: The Holocene. Vol. 13, No. 6, 2003, pp. 941-948, doi : 10.1191 / 0959683603hl682fa .
- Carey Krajewski, Amy C. Driskell, Peter R. Baverstock , Michael J. Braun: Phylogenetic relationships of the thylacine (Mammalia: Thylacinidae) among dasyuroid marsupials: evidence from cytochrome b DNA sequences. In: Proceedings of the Royal Society of London . Series B: Biological Sciences. Vol. 250, No. 1327, 1992, pp. 19-27, PMID 1361058 , doi : 10.1098 / rspb.1992.0125 .
- Paul S. Martin , Richard G. Klein (Eds.): Quaternary Extinctions. A Prehistoric Revolution. The University of Arizona Press, Tucson AZ 1984, ISBN 0-8165-1100-4 .
- David Pemberton, Deane Renouf: A field-study of communication and social behavior of Tasmanian Devils at feeding sites. In: Australian Journal of Zoology. Vol. 41, 1993, pp. 507-526.
- Lars Werdelin: Some observations on Sarcophilus laniarius and the evolution of Sarcophilus. in: Records of the Queen Victoria Museum. Vol. 90, 1987, ISSN 0085-5278 , pp. 1-27.
Documentary film
- Animals in front of the camera: The nights of the Tasmanian Devils . German television documentary by Ernst Arendt and Hans Schweiger . Bayerischer Rundfunk 1988, approx. 43 minutes
- Tasmania, sympathy for the devil . 360 ° geo report. arte, Germany, France 2014 [1]
Web links
- Sarcophilus harrisii in the Red List of Threatened Species of the IUCN 2011. Posted by: Hawkins, CE, McCallum, H. Mooney, N., Jones, M. & Holdsworth, M., 2008. Accessed September 8, 2011th
Individual evidence
- ↑ Don E. Wilson, DeeAnn M. Reeder (Ed.): Mammal Species of the World. Volume 1. 3rd edition. 2005.
- ↑ Eric R. Guiler: Tasmanian Devil. In: Ronald Strahan (Ed.): Complete Book of Australian Mammals. The national photographic index of Australian wildlife. Angus & Robertson, London 1983, ISBN 0-207-14454-0 , pp. 27-28.
- ↑ Stephen Wroe, Colin McHenry, Jeffrey Thomason: Bite club: comparative bite force in big biting mammals and the prediction of predatory behavior in fossil taxa. In: Proceedings of the Royal Society of London . Series B: Biological Sciences. Vol. 272, No. 1563, 2005, pp. 619-625, PMID 15817436 , doi : 10.1098 / rspb.2004.2986 .
- ↑ Hamish McCallum, Menna Jones: To Lose Both Would Look Like Carelessness: Tasmanian Devil Facial Tumor Disease. In: PLOS Biology . Vol. 4, No. 10, 2006, e342, doi : 10.1371 / journal.pbio.0040342 .
- ↑ Bjarne Braun: Devil Facial Tumor Disease - a contagious cancer . August 13, 2012.
- ↑ Webb Miller, inter alia: Genetic diversity and population structure of the endangered marsupial Sarcophilus harrisii (Tasmanian devil). In: Proceedings of the National Academy of Sciences of the United States of America . Vol. 108, No. 30, 2011, pp. 12348-12353, doi : 10.1073 / pnas.1102838108 .
- ↑ Rachel Sullivan: Human intervention speeds up devil cancer evolution. ABC News of March 17, 2014.
- ↑ Tasmanian Devil: Evidence of resistance to deadly disease discovered. Spiegel ONLINE from March 10, 2010.
- ↑ Nadja Podbregar: Devilish Tumors. On: Wissenschaft.de on March 11, 2013. Accessed on September 8, 2019.
- ↑ Nick Beeton, Hamish McCallum: Models predict that culling is not a feasible strategy to prevent extinction of Tasmanian devils from facial tumor disease . In: Journal of Applied Ecology . Vol. 48, No. 5, 2011, pp. 1315-1323. doi : 10.1111 / j.1365-2664.2011.02060.x .
- ↑ Martin Vieweg: Fear for a devil. On: Wissenschaft.de on October 6, 2011. Accessed on September 8, 2019.
- ↑ Save the Tasmanian Devil Program acknowledges 10 years of support , website of the "Save the Tasmanian Devil Program" (a project of the Australian and Tasmanian governments), online at: tassiedevil.com.au / ...
- ↑ Wild Devil Recovery , website of the "Save the Tasmanian Devil Program" (a project of the Australian and Tasmanian governments), online at: tassiedevil.com.au /.../ wild ...
- ↑ Tasmanian Devil Insurance Population , Report of the Zoo and Aquarium Association (ZAA), https://www.zooaquarium.org.au/index.php/tasmanian-devil-insurance-population/
- ^ Information on Tasmanian Devil Conservation Park ( Memento from February 11, 2009 in the Internet Archive ). Retrieved July 18, 2015.
- ↑ Tasmanian devil - Frequently Asked Questions ( Memento from February 20, 2007 in the Internet Archive )
- ↑ Linus Torvald's Blog - New Logo
