Sarcophilus harrisii (Dasyuromorphia: Dasyuridae)

Sarcophilus harrisii (Dasyuromorphia: Dasyuridae)Sarah E. Magnuson, Nathan Swigart, and Marissa WeidensaulWildlife and Fisheries Science, Pennsylvania State University, Pa 16801, USA; sem5442@psu.eduWildlife and Fisheries Science, Pennsylvania State University, Pa 16801, USA;nms5261@psu.eduAgricultural Science, Pennsylvania State University, Pa 16801, USA;mkw5146@psu.eduAbstract: Sarcophilus harrisii (Boitard 1841) is a small carnivorous marsupial native to Tasmania, an island off the coast of Australia. It is commonly known as the Tasmanian devil. After the extinction of the Tasmanian wolf, the devil became Tasmanias largest predator. Tasmanian devils have a negative reputation because of their loud fierce noises and aggressive behavior. Recently, a disease, known as Devil Facial Tumor Disease, has depleted much of the native populations. Many conservation groups and government agencies now work to find a cure and save the future of this ecologically important species. Keywords: Tasmanian devil, Devil Facial Tumor Disease, Tasmania, marsupial, carnivore, endangered, sclerophyll, scavengerSynonymies Didelphis ursina Harris, 1807 Sarcophilus hariisi Boitard, 1841Context and Content Order Dasyuromorphia, family Dasyuridae, subfamily Dasyurinae, tribe Dasyurini. Sarcophilus harrisii is monotypic. (Mammal Species of the World. 2005).DiagnosisBeing of the same genera, Tasmanian devils share similar traits to koalas. Even with their similarities, Tasmanian devils have quite a few differences that separate them from other marsupials. Compared to the koala, Tasmanian devils tend to have an aggressive personality. Being notorious for their loud screeching noises, Tasmanian devils were named according to their aggressive behavior. Living mainly off meat, these carnivorous creatures are built for this life style. Compared to other carnivorous marsupials in the world, Tasmanian devils are the largest of their kind. Having a large head and thick neck, these mammals can use secodont teeth to sheer through flesh with a bit force of 1,200lbs per square inch. This makes chewing through prey such as snakes, birds, fish, and insects an easy task. Tasmanian devils have a muscular build where much of their strength is generated. These fierce creatures are built for speed and endurance. A Tasmanian devil can reach 15 mph and maintain that pace for up to an hour. The life expectancy of devils are 7-8 years, which, is short compared to the 10-14 years life expectancy of koalas .(Fun Facts about Tasmanian Devils. 2013).(Tasmanian Devils. Department of Primary Industries, Parks, Water, and Enviroment. 2013).Compared to a koala, Tasmanian devils are loud animals, unlike koalas which are quite in nature. Koalas being herbivores, while Tasmanian devils are carnivores. Adults can weigh up to 10 kg and they will eat up to 5 -10 % of their body weight a day, averaging up to 1 kg of food in a day. Tasmanian devil females tend to be smaller than males and only reach 8-9 kg and males reach 10-11 kg. As koalas were built to spend their time mainly in the tree, Tasmanian devils spend most their time on the ground. They stand about 30 centimeters at the shoulder with having big heads that look almost as big as their bodies. (Fun Facts about Koalas. 2013). (Tasmanian Devils. Department of Primary Industries, Parks, Water, and Enviroment. 2013).Being mammals, both animals give placental birth to their young, but as marsupials, the undeveloped young are kept within a pouch that include mammary glands until the young have developed properly. Both Tasmanian devils and koalas have a keen sense of smell, although, devils use this sense for hunting their prey whereas koalas use this sense to smell predators. Physically, both animals have a bear-like appearance even though they are not even related. (Fun Facts About Tasmanian Devils. 2013). (Tasmanian Devils. Department of Primary Industries, Parks, Water, and Enviroment. 2013).CharacteristicsTasmanian devils were discovered by European travelers who gave them their name due to their behavioral issues and loud screeching noise they produce. With their baby bear-like appearance, they have brown to black thick fur. They have white band like markings across their chest and white accents towards their rumps. They can reach the length of 30 inches and a weight of 26lbs, a size of a small dog. Tasmanian devils are very muscular and have a pig-like gate. Their front legs are long while their rear legs are short. When scared or intimidated, devils have the ability to open their mouths very wide. Devils display this behavior when they are faced with predators or want to fight with another devil. Although, devils do not have many predators, small devils may fall into the claws of eagles, owls, and spotted tail quolls.Tasmanian devils are very solitary animals but often eat together. Their eating habits consist of an unusual behavior. They first rip out the digestive system of their prey for its the softest part of the anatomy. Devils store fat in their tails, if their tail appears very skinny and limp, this means the animal is unhealthy. They can consume in one day five to ten percent of their body weight and on occasions if the event transpires they will and can eat up to forty percent of their body weight in thirty minutes. Devils are very open to what they eat and are not, picky eaters, and will consumer anything and will eat all parts of an animal body. They even consume many parts of the body that no other animal would think of such as, hair, bones, and organs.(Fun Facts about Tasmanian Devils. 2013). (Tasmanian Devil. National Geographic. 2013).Distribution The Tasmanian devil is found throughout the island of Tasmania on the Southern end of Australia and is listed as an endangered species under the Tasmanian Threatened Species Act 1995. The Tasmanian devil is only found in Tasmania but once lived throughout the Australian mainland approximately 400 years ago. Due to competition with rising populations of dingoes and an increase in arid environments, their numbers declined and they were extirpated from that area (Australian Government. 2009). Tasmanian devils were also thought to be absent from Badger Island, which is located off the North West shore of Tasmania. Extensive research has been conducted to estimate and monitor the Tasmanian devil population on Badger Island and in the mid 1990's it was decided to introduce them to the island. This population of Tasmanian devils was then monitored by using different techniques including hair tubing and spotlight surveys, in 2005 their numbers had decreased significantly and are again thought to be absent from Badger island (Australian Government. 2009). Now Tasmanian devils have a continuous distribution across Tasmania with a range of 10,000-25,000 mature individuals. Tasmanian devils are monitored heavily throughout Tasmania due to their declining numbers and studies show that their densities are extremely low in the south-west part of the island and highest in the eastern half and north-west coast of Tasmania. Researchers believe Tasmanian devil numbers are higher in the eastern half and north-west half because of better suited habitat in the mixed sclerophyll forests (Australian Government. 2009). Form and FunctionForm Tasmanian devils have thin skin that is covered in black fir with white markings across the chest that extend back to the shoulders and a white line that crosses their rump and is perpendicular to their tale (Australian Government. 2009). At first, the Tasmanian devil was thought to be a species of opossum and was categorized as Didelphis ursina because of its bear like resemblance, it was then relegated and categorized under Sarcophilus along with S. laniarius and S. moomaensis from the Pleistocene era. Tasmanian devils were then given the name Sarcophilus harrisii. The Tasmanian devil belongs to the genus Dasyuridae and is believed to be closely related to quolls, which is a carnivorous marsupial native to mainland Australia (devils@cradle. 2008). The Tasmanian devil has a skull with akinetic joints that only allow their mouth to be opened to a certain point, they have a single lower mandible and a complete zygomatic arch. Tasmanian devils have two occipital condyles so they can move their skull independently from the rest of their body and twenty four vertebrae, their scapula is fused to their spine to increase strength. The front legs of Tasmanian devils tend to be unique compared to other marsupials because they are longer than their back legs, they also have five toes and are plantigrade. Tasmanian devils have heterodont teeth which allows them to be a generalist species when it comes to feeding, they will feed on invertebrates, fledgling birds, small mammals, lizards and carrion. They have polyprodont incisors, well developed canines, and usually six or seven sharp cheek teeth for catching and killing prey, their dental formula is I4/3; C1/1; PM 2/2; M4/4 with a total of 20 teeth (Encyclopedia Britanica. 2013). Tasmanian devils are endothermic and have a four chambered heart that circulates enucleated red blood cells throughout their body. The blood is warmed by using energy obtained from food and converted into heat. Blood is then pumped through the heart and is circulated through the lungs where it becomes oxygenated, then flows to the brain and the rest of the body through millions of capillaries (Natural History Collection. 2006). The central nervous system of the Tasmanian devil is not as complex as that of other mammals. Tasmanian devils along with other marsupials lack convolutions in their brain. Their brains appear to be smooth and not "bumpy" like well developed eutherians (Natural History Collection. 2006). Since the central nervous system is less developed the peripheral nervous system, which relays messages from the body to the central nervous system, also tends to be less developed in Tasmanian devils (Natural History Collection. 2006). The Tasmanian devil has a simple digestive system, meaning that it does not regurgitate its food. Tasmanian devils have a single chambered stomach and its intestines and stomach are not particularly enlarged. Food travels from the mouth, through the esophagus and into the stomach where it is broken down by acids. The small intestine receives the food first and nutrients are absorbed into the bloodstream then it is pushed along with villi then into the large intestine. The large intestine lacks villi but it gives more nutrients to the blood stream and then the waste is pushed out of the anus (Grzelewski, D. 2010). The urogenital system of Tasmanian devils is not complex like some other marsupials, instead the females have a single vagina and the males have a single headed penis (National Museum Australia. 2013). FunctionMetabolic rate of Tasmanian devils show a constant increase and decrease over a period of six hours at 15 and 10C during sleep state. The metabolic rate of Tasmanian devils starts at ~3.0W/kg then drops to ~2.0W/kg at 15C then the animal starts to shiver to bring its body temperature back up to 35.7C. When the temperatures were dropped to 10C the metabolic rate of the Tasmanian devils increased and had more prolonged times when their metabolic rate was higher. The highest metabolic rate recorded at 10C was ~4.0W/kg and it dropped to ~2.0W/kg very infrequently during the testing time (Nicol, S. 1980). Tasmanian devils are endothermic and maintain an average body temperature of 35.7C through the use of energy obtained by food and using the energy to raise their metabolic rate when needed. Tasmanian devils have a lower critical temperature of 28.5C and an upper critical temperature of 37C. When Tasmanian devils reach or go below their lower critical Temperature they increase their metabolic rate by shivering to increase their body temperature, Tasmanian devils cool themselves by evaporative cooling through panting when they reach or go past their upper critical temperature. Tasmanian devils obtain their water mainly from their prey since living mammals are composed primarily of water. Tasmanian devils store fat in their tails and this is where they store water as well (Nicol, S. and M., Maskrey. 1980). Tasmanian devils do not show any sign of torpor or hibernation even in severe winter weather conditions. Tasmanian devils are just as active during times of severe weather throughout the entire year, although it is believed they spend more time in burrows during hard times. Tasmanian devils also have a daily flux in body temperature in which their body temperature increases in the evening and through the night and decreases during the day (Nicol, S. and M., Maskrey. 1980). Female Tasmanian devils come into heat around March and April, they will be able to find plenty of food due to abundant prey during the spring and summer months. During the breeding season females will ovulate in a 21 day period and copulation can take 5 days (Guiler. 2013). Tasmanian devil's eyes are located toward the front of their heads so they have greater binocular area and a small field of view compared to their prey species which have eyes located on the sides of their head. The eyes of the Tasmanian devil are primarily composed of cones and they see in black and white. As a result they have increased eye sight during night time hours. Tasmanian devils do not echolocate but have a great sense of hearing to which they use primarily to detect their prey along with their predators (Encyclopedia Britanica. 2013). Ontogeny and ReproductionOntogenyTasmanian devils are mammals and give birth to live young. Tasmanian devils are also marsupials so they give birth early in the gestation process. Tasmanian devils have a short gestation period of only three weeks. When the young is born, they are hairless and lack facial features. Only its arms are developed enough to be used. The young weigh about 0.2 grams. When Tasmanian devils are born they climb up the mother's stomach and go into her marsupium where her nipples are located. The young stay in the marsupium for 100 days, during this time they finish their development (Guiler. 2013). During the second week the nose starts to become defined and the ears start to grow after fifteen days, at sixteen days the eyelids start to form and at seventeen days whiskers grow and at twenty days lips start to develop. After eight weeks the young start to make squeaking noises. Then, at ten weeks, they are able to open their lips. The young are still pink at this point but they start growing fur around forty nine days and have a full coat around ninety days. After their fur coat develops their eyes open between eighty seven and ninety three days, they then relax their grip on the nipple at one hundred days and are ejected out by the mother after one hundred and five days after birth. The young stay in the den for three month with the mother. Then after six months they begin to disperse. Tasmanian devils become sexually mature when they are two years old and start reproducing in the spring of their second year (Guiler. 2013). Reproduction Female Tasmanian devils have a twenty one day period in which they come into estrous during March or April in which they can copulate three times. Males begin spermatogenesis in mid February (Scientific Amaerican. 2011). During conception, a male and female Tasmanian devil will go into their den for five days to impregnate the female. Female Tasmanian devils have a three week gestation period in which the young begin to develop. After the three weeks, the female gives birth to 20-30 young while standing up in the den (Guiler 2013).EcologyPopulation characteristics Devils can be seen in all native terrestrial habitats in Tasmania. Tasmanian devils can be found from sea level all the way up to some of the highest peaks (Jones and Rose 1996). Before the discovery of DFTD population densities were the lowest in the plains of the south west and the highest in the forests in the eastern and north western side of the island. While many populations can be found just about everywhere in Tasmania, population densities tend to be the highest in mixed patches of grassland used for grazing and forest (Jones and Rose 1996). It seems that the devils tend to use lowlands for travel but avoid steep slopes are rocky areas because they do not tend to have efficient food sources.Space use No matter where a group or individual Tasmanian devil is found, they all exploit the environment the same. One single devil tends to have a moderately sized home range as long as it has efficient resources for their lifestyle (Nowak 1991). Many Tasmanian devils may have home ranges that overlap. A typical home range size ranges from about 4 km2 to 27 km2 (Pemberton 1990). Within these home ranges are the Tasmanian devils dens. In some cases devils have been known to exploit old wombat burrow (Owen and Pemberton 2005). They prefer for their dens to be in dense forest with thick grasses, however if near settled areas they will build dens under buildings. Unknown to many, devils stay faithful to their dens for their entire life, going back to the same den to raise their young. While not using those dens, typically they will make small nests of bark, grasses, and leaves to use throughout the day (Tasmanian 2012).Tasmanian devils are nocturnal mammals, meaning they travel at night but other than that it does not seem that the devils movements are based on season. It does seem that movement is reduced when the females have young to protect in the dens (Owen and Pemberton 2005). However, longer range movements are seen in winter. Diet Tasmanian devils are carnivores but more importantly scavengers (Tasmanian 2012). Historically, people blamed the devils for eating livestock. However, the main part of a devils diet is carcasses of dead animals such as sheep, rabbits, and wombats (DPIWE 2005). When eating the carcasses, devils do not only eat the animal flesh, but the whole carcass including the bones and fur. If a carcass is no available, they will resort to eating insects, snakes, and sometimes even small amount of vegetation. Tasmanian devils are not fast foragers, but extremely slow foragers. They do this so they can use their keen sense of smell to detect where food may be (DPIWE 2005). Normally the devils will move slowly in a typical gait but can run quickly when both hind feet are together. When they do forage it is very typical for it to be done in small groups. However if a carcass cannot be found, devils have been known to even hunt prey. When they hunt they tend to use ambush techniques done at moderate speeds for a short period of time (Jones 1996).Disease and parasites Unfortunately for this species, a disease has caused much of the native Tasmanian devil to perish. Devil Facial Tumor Disease is an infectious disease that is very easily transmitted (McCallum et al 2007). It is believed that if a devil is bitten by another devil that is carrying the disease when fighting over food or during breeding season that the disease will be transmitted. Other than transmission through biting, cannibalism is very common in this species, which causes a lot of concern because the disease will be transmitted if ingested (Pfennig 1998). This disease has caused a huge loss of the older adults which means many populations are comprised of younger devils. It is believed that due to this disease many females may not live to see sexual maturity at two years old (Lachish et al 2007). Other than disease, Tasmanian devils happen to be very important for a parasite. Devils are the only known host to the currently the only threatened invertebrate, a tapeworm called Dasyurotaenia robusta, which is listed as rare. Interspecific interactionsTasmanian devils do not have to deal with much competition from other species, because they have very few natural predators. Historically the Tasmanian wolf was the main predator of the devils but since they have gone extinct very few species will challenge a devil. Adult Tasmanian devils tend to stay unchallenged, however young devils can fall prey to eagles, owls, and even tiger quolls (DPIWE 2005). Young devils are not completely terrestrial, it has been documented that young devils are quite agile and because of this are able to climb trees (Tasmanian 2012). This characteristic could help them avoid predation. When attacked, devils act very aggressively. They use their jaws and teeth are their main weapons due to the fact that they tend to have a jaw stronger than most carnivores of equal size. It is believed that because of the presence of the Tasmanian wolves that the devils became nocturnal to avoid predation. Miscellaneous Many techniques used to observe other carnivores have also been employed with Tasmanian devils such as radio collars, camera traps, and spool and line tracking. Spool and line tracking is an inexpensive way to track and record the movements of small mammals in a variety of different habitats (Steinwald et al 2006). Tasmanian devils tend to show the same reactions and perform the same actions in captivity as they do in the wild. They will still battle over food just like they do in the wild (Nowak 2001). However in captivity, it has appeared that some groups have started to use a learned dominance hierarchy which is not present in wild species. Along with these things, longevity also tends to be longer in captivity. This could be mainly due to the control of transmission of DFTD done in captivity. BehaviorGrouping behavior Tasmanian devils have been known for their seemingly aggressive behavior. However, Tasmanian devils tend to only be aggressive when it comes to feeding. When a group of individuals congregate around a food source such as a carcass, they will act aggressively towards each other (DPIWE 2005). Typically, however, that is the only time aggression is seen, because the species does not tend to be territorial (Guiler 1970). While there are times that devils will travel in groups, the species as a whole has been documented to be relatively solitary. Unfortunately, not many studies have been performed to look at the social organization and behavior of Tasmanian devils. However, it has been documented that even though the devils are not territorial, they will fight each other over food and mates. When they do so, fighting can get very aggressive leaving one of the animals injured (Nowak 1991). Another view on this is that the Tasmanian devils have aggressive displays such as a yawn that is not done out of aggression but fear and uncertainty. However this action can be mistaken as aggression (Tasmanian 2012). It is believed that Tasmanian devils will let out a lot of fierce noises which is discussed further in the communication section. A sharp sneeze can be used to challenge another devil however it is thought that all the aggressive behavior and noises are just bluff to avoid harmful fighting (Tasmanian 2012). Tasmanian devils are quite misunderstood and always considered aggressive, but they can be seen sunbathing during the day in very quiet areas this action shows that they also have a calmer side (Nowak 1991).Reproductive behaviorThe Tasmanian devil is known as a promiscuous species, meaning that they do not have one specific mate their entire lives but different mates every breeding season. The males will mate with many females in one season. It has also been observed that females are extremely selective of what females they chose for mating (Owen and Pemberton 2005). Females have been known to choose a mate based on who is the strongest and has the most experience. To determine this, males will engage in two different types of displays. One way is through a physical battle with one another which often result in injuries. Another way is through a ritual battle which often if a fight with not actual harm to either competitor (Owen and Pemberton 2005). Once the female picks a male, the male will then grab the female by the neck and physically drag them back to their den and mate with them. Tasmanian devils have very unconventional mating techniques. For example, males will keep the females subdued and held captive in their dens for long periods of time with no food or water. While doing this, he will continue to guard her from other potential mates. Males will mate with this female until out competed by another male or until the female drives him away (Owen and Pemberton 2005). Communication Tasmanian devils have been well known for their extensive communication repertoire. They are able to communicate through vocalizations such as growling and physical cues such as raising their tails. Tasmanian devils use many different types of vocalizations. When battling over a food source, they are known to let out high pitched blood curdling shrieks and low pitched growls (DPIWE 2005). Physically they have been known to raise their tails to show aggression and yawn to show fear. One prominent vocalization is when a devil produces a sharp sneeze; this usually indicates a challenge to other devils. However, many people believe that all these vocalizations and physical cues are a bluff to make other predators and other devils believe that they are bigger and tougher than actual reality (Tasmanian 2012). Another action that normally gets overlooked is the fact that devils produce a very strong odor when they become stressed but immediately after they are no longer under stress the smell disappears. ConservationSince May of 2008, the Tasmanian devil has been listed as an Endangered Species under the Tasmanian Governments Threatened Species Protection Act 1995 and as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999. Many other programs have been put into place to save the devils, for example the Save the Tasmanian Devil Program which focuses on further research of Devil Facial Tumor Disease. They hope to find a cure for this disease in hopes to save further populations from perishing to this awful disease. Other than the disease taking a toll on the species, it used to be believed that the devils are in danger due to persecution by local people and by destruction of their habitats (Bradshaw and Brook 2005). The best ways to ensure the future of this species is to control the disease but also educate the local people about these animals to ensure they are not being killed and their environment is not being destroyed.Tasmanian devils have both positive and negative ecological importance to humans. One positive ecological importance to humans is that the devil is the top predator to native Tasmania. Another positive ecological effect is that they are very important for removing unwanted carcasses (Nowak 1991). A negative effect on ecology however that they play to humans is that they have been known to kill livestock and poultry, which has been proved to be false, but because of this the devils are known as a nuisance (DPIWE 2005). Due to this, it is still believed that the positive effects greatly outweigh the negative effects between humans and the Tasmanian devil populations.

Figures

Figure 1: Shows the distribution and range map of the Tasmanian devil represented in red. (Australian Government. 2009)

Figure 2: Live photo of a wild Sarcophilus harrisii (IUCN 2008)

Figure 3a: This figure shows the dorsal view of the skull of Sarcophilus harrisii (Forbes 1994)

Figure 3b: This figure shows the ventral view of the skull of Sarcophilus harrisii (Forbes 1994)

Figures 3c: This figure shows the side view of the entire skull of Sarcophilus harrisii (Forbes 1994)Literature CitedAustralian Government. 2009. Biodiversity Species Profile and Threats Database. Sacrophilus harrissii-Tasmanian Devil. Accessed 17 March 2013.Bradshaw, C., B. Brook. 2005. Disease and the devil: density-dependent epidemiological processes explain historical population fluctuations in the Tasmanian devil.Ecography, 28: 181-190.Devils@cradle. 2008. tasmanian devil sanctuary, cradle mountain, tasmania. devil facts, tasmanian devil sacrophilus harrissii. Accessed 14 March 2013. Don E., Wilson, and Deeann M., Reeder . 2005. Mammal Speciesof the World. A Taxonomic and Geographic Reference (3rd ed), Johns Hopkins University Press, 2,142 pp. http://www.press.jhu.edu, accessed 30 March 2013.

DPIWE, Nature Conservation Branch, 2005. "Tasmanian Devil Facial Tumour Disease" (On-line). Department of Parks, Industries, Water, and Environment, Tasmania. Accessed June 24, 2005 at http://www.dpiwe.tas.gov.au/inter.nsf/WebPages/JCOK-65X2Y6?open.

Encyclopedia Britannica. 2013. Britannica online Encyclopedia. Tasmanian devil. < http://www.britannica.com/EBchecked/topic/583942/Tasmanian-devil>. Accessed 15 March 2013.Forbes, R.B. Sarcophilus Harrisii - #1283-#1285. 1994. Photograph. American Society of Mammalogists. American Society of Mammalogists. Web. 30 Mar. 2013. .Fun Facts About Tasmanian Devil. 25 Feb. 2013. LiveScience. www.livescience.com/27440-tasmanian-devils.html, accessed 30 March 2013.

Fun Facts About Koalas. 25 Feb. 2013. LiveScience. www.livescience.com/27401-koalas-facts.html, accessed 30 March 2013.

Grzelewski, D. 2010. Dining with the Tasmanian devil. Australian Geographic 70:26-29. < http://www.australiangeographic.com.au/journal/dining-with-the-tassie-devil.htm> Accessed 18 March 2013.Guiler, ER (1970) . Obsevations on the Tasmanian Devil, Sarcophilus harrisii (Marsupialia : Dasyuridae) I. Numbers, home, range, movements and food in two populations. Australian Journal of Zoology 18 , 4962.Guiler, E. R. 1982. Temporal and spatial distribution of the Tasmanian Devil,Sarcophilus harrisii(Dasyuridae: Marsupialia).Papers and Proceedings of the Royal Society of Tasmania116: 153-163.Jones, M. E. 2001. Large Marsupial Carnivores. In: D. Macdonlad (ed.),The New Encyclopedia of Mammals, Oxford University Press, Oxford, UKJones, M. E. and Rose, R. K. 1996. Preliminary assessment of distribution and habitat associations of the spotted-tailed quoll (Dasyurus maculatus maculatus) and eastern quoll (D. viverrinus) in Tasmania to determine conservation and reservation status. Report to the Tasmanian Regional Forest Agreement Environment and Heritage Technical Committee. Tasmanian Public Land Use Commission, Hobart, Tasmania.Lachish, S., Jones, M. and McCallum, H. 2007. The impact of devil facial tumour disease on the survival and population growth rate of the Tasmanian devil.Journal of Animal Ecology76: 926-936.McCallum, H., Tompkins, D. M., Jones, M., Lachish, S., Marvanek, S., Lazenby, B., Hocking, G., Wiersma, J. and Hawkins, C. E. 2007. Distribution and impacts of Tasmanian Devil Facial Tumour Disease.Ecohealth4: 318-325National Museum Australia. 2013. Collection Service. Wet specimen-Tasmanian Devil-reproductive system. < http://www.nma.gov.au/collections-search/display?irn=64958> Accessed 15 March 2013.Natural History Collection. 2006. Natural History Collections online. Dasyurids Marsupial carnivores. < http://www.nhc.ed.ac.uk/index.php?page=24.134>. Accessed 10 March 2013.Nicol, S. and M., Maskrey. 1980. Thermoregulation, respiration and sleep in the Tasmanian devil, Sacrophilus harrissii (Marsupialia: Dasyuridae). Journal of comparative physiology 140(3): 241-248. Accessed 15 March 2013.Nowak, R. 1991. Walkers Mammals of the World.Baltimore: Johns Hopkins University Press.Owen, D. and Pemberton, D. 2005.The Tasmanian devil: a unique and threatened animal. Allen & Unwin, Australia.Pemberton, D. 1990. Social organisation and behaviour of the Tasmanian devil,Sarcophilus harrisii. University of Tasmania.Pfennig, D. W., Ho, S. G. and Hoffman, E. A. 1998. Pathogen transmission as a selective force against cannibalism.Animal Behaviour55: 1255-1261Scandizzo, V. and Chris, C. 2005. Husbandry Manual of Tasmanian Devil Sacrophilus harrissii (Mammalia: Dasyuridae). Western Sydney Institute of TAFE, Richmond College. Accessed 13 March 2013.Scientific Amaerican. 2011. Blog. Sperm Bank and Reproductive Research Could Help Save Tasmanian Devils from Extinction. < http://blogs.scientificamerican.com/extinction-countdown/2011/12/14/sperm-bank-could-save-tasmanian-devils-from-extinction/> Accessed 13 March 2013. Steinwald, Mary C., Swanson Bradley J., et al. 2006. Effects of Spool- and- line Tracking on small desert mammals. The Southwestern Naturalist. 51, 71-78.Tasmanian Devil. Department of Primary Industries, Parks, Water, and Enviroment.Web. 4 April.2013..

Tasmanian Devil. 2013. 2013. National Geographic. http://animals.nationalgeographic.com/animals/mammals/tasmanian-devil, accessed 30 March 2013.

Tasmanian devil, Sarcophilus harrisii. 2012.Tasmania Parks and Wildlife Service. http://www.parks.tas.gov.au/index.aspx?base=387, accessed 21 March 2013.