|The Tasmanian devil is the largest, native, mammalian predator on Tasmania and the world’s largest carnivorous marsupial. This robust, nocturnal marsupial is endemic to Tasmania and was given its name when early explorers heard its unique, devil-like shrieks and discovered its powerful jaws and teeth.|
Tasmanian devils have a stocky, thick-set, squat build with a relatively low center of mass.
Unusual for a marsupial, the Tasmanian devil’s forelegs are slightly longer than its hind legs. They have five long toes on their forefeet, four pointing to the front and one coming out from the side, which gives the devil the ability to hold food. The hind feet have four toes. Tasmanian devils have non-retractable claws.
The head of the Tasmanian devil is massive and broad with well-developed jaw muscles. Their big, strong molar teeth are heavy and adapted for their role in crushing bone and tearing through muscle and thick skin.
As in many dasyurids, Tasmanian devils store body fat in their tails, and healthy devils have fat tails. The tail is largely non-prehensile and is important to the devil’s physiology, social behavior, and locomotion, acting as a counterbalance to aid stability when the devil is moving quickly. An ano-genital scent gland at the base of its tail is used to mark the ground behind the animal with its strong, pungent scent.
The Tasmanian devil’s fur is usually brownish black with irregular white patches, although approximately 16% of wild devils do not have white patches. They can have white patches on the throat and white spots on their sides and rump. These markings are thought to aid the Tasmanian devil with its nocturnal lifestyle, allowing it to hide amongst the darkness. They’re also believed to draw biting attacks toward less important parts of the body as fighting between devils often leads to a concentration of scars in these regions. The insides of the Tasmanian devil’s ears are often red or pink, as well as the snout.
The Tasmanian devil is the largest surviving carnivorous marsupial. The body size of the Tasmanian devil varies considerably with diet, habitat, and age. Female Tasmanian devils are slightly smaller than males. Large males may reach 12 kilograms (26 pounds) and 30 centimeters (12 inches) at the shoulder. Their total length ranges from 52 to 80 centimeters (20-32 inches) and their tail length ranges from 23-30 centimeters (9-12 inches), about half the devil’s body length. Male weight ranges from 5.5 to 12 kilograms (12-26 pounds), averaging 8 kilograms (18 pounds) and female weight from 4.1 to 8.1 kilograms (9-18 pounds), averaging 6 kilograms (13 pounds). Females tend to have an average head and body length of 57 centimeters (22 inches) and a 24.4 centimeter tail (9.6 inches) tail. Tasmanian devils in western Tasmania tend to be smaller.
Imp, Joey, Pup
S. h. dixonae (Extinct)
S. h. harrisii (Endangered)
The Tasmanian devil got its name from early European settlers who upon hearing far-reaching, mysterious, unearthly screams, coughs, and growls from the bush, decided to investigate further. Finding the dog-like animal with red ears, wide jaws and big, sharp teeth led them to call it The Devil. Beelzebub’s pup was another early explorer vernacular name, in reference to a religious figure who is a prince of Hell and an assistant of Satan.
The Tasmanian devil’s scientific name, Sarcophilus harrisii, translates to Harris’ flesh-lover. Related names that were used in the 19th century were Sarcophilus satanicus (Satanic flesh-lover) and Diabolus ursinus (bear devil), all due to early misconceptions of the devil as implacably vicious.
In 1807, naturalist George Harris wrote the first published description of the Tasmanian devil, naming it Didelphis ursina due to its opossum- and bear-like characteristics, such as rounded ears. He also presented on the species at the Zoological Society of London. However, that particular binomial name had already been given to the common wombat, (later reclassified as Vombatus ursinus) by George Shaw in 1800, and was hence unavailable. In 1838, Richard Owen named a specimen Dasyurus laniarius, but by 1877, h e had relegated it to Sarcophilus. The current scientific name, Sarcophilus harrisii was adopted by French naturalist, Pierre Boitard in 1841.
A later revision of the devil’s taxonomy, published in 1987, attempted to change the species name to Sarcophilus laniarius based on mainland fossil records of only a few animals. However, this was not accepted by the taxonomic community at large. The name S. harrisii has been retained and S. laniarius relegated to a fossil species.
The Tasmanian devil belongs to the family Dasyuridae. The genus Sarcophilus contains two other species, known only from Pleistocene fossils: S. laniarius and S. moomaensis. Phylogenetic analysis shows that the Tasmanian devil is most closely related to quolls.
Currently, Tasmanian devils are found only in Tasmania, although widespread fossil evidence suggests that they once occupied much of the Australian mainland.
It is believed the devil became extinct on the mainland some 3,000 years ago, before European settlement. It has been suggested that their absence in many previously occupied areas can be explained by increasing aridity and competition with the introduced dingo (Canis lupus dingo). The dingo was prevented from entering Tasmania by the Bass Strait.
Despite the decline in numbers since the early 1990s, populations of Tasmanian devils remain widespread in Tasmania from the coast to the mountains. Tasmanian devils are numerous throughout Tasmania except in areas where there has been extensive habitat fragmentation and deforestation.
Tasmanian devils are most numerous in coastal heath and rangeland areas where agricultural practices maintain a constant supply of carrion. They also occur in open, dry schlerophyll forest and mixed schlerophyll-rainforest.
Tasmanian devils have been known to take advantage of the interface between native habitat and agricultural paddocks, where their favorite prey species are often found.
Tasmanian devils are generally nocturnal, but they may be seen sunbathing during the day in quiet areas. They typically inhabit their dens and dense bushes throughout the day. Their nocturnal activity may help them avoid some predators, such as thylacines (Thylacinus cynocephalus), historically.
Tasmanian devils are usually solitary. Occasionally, when individuals congregate at food sources, such as carrion, they interact aggressively but they are not territorial. Many of their auditory and display behaviors are bluff and part of a ritual to minimize harmful fighting when feeding communally at a large carcass. There also seems to be a learned dominance hierarchy, at least in captive situations.
The famous gape or yawn of the Tasmanian devil that looks so threatening, can be misleading. This display is performed more from fear and uncertainty than from aggression. Tasmanian devils also produce a strong odor when under stress, but when calm and relaxed they are not smelly. Tasmanian devils are ferocious when attacked, however, and because they are impressively armed with heavy jaw musculature and robust teeth, they are able to protect themselves against larger predators.
Tasmanian devils have keen senses of smell, sight, touch, and taste. They communicate through a wide variety of vocalizations and physical cues, such as yawning and raising their tails.
The Tasmanian devil makes a variety of fierce noises, from harsh coughs and snarls to high pitched screeches. They have an especially impressive and frightening screech. Tasmanian devils also vocalize with growls and vibratos when fighting and are regarded with awe because of the blood-curdling shrieks they use when a group is scavenging a carcass. A sharp sneeze is used as a challenge to other devils, and frequently comes before a fight.
Although Tasmanian devils are not territorial, they stay within relatively small home ranges. Home ranges can be very large if resources are scarce, however. They can roam considerable distances, up to 16 kilometers, along well-defined trails in search of food and average 3.2 kilometers, or 2 miles, traveled in a night in search of food. Both males and female Tasmanian devils make simple nests of bark, grass, and leaves, which they inhabit throughout the day. Their dens are typically located in hollow logs, caves, or burrows.
Tasmanian devils usually amble slowly with a characteristic gait but can gallop quickly with both hind feet together. Devils can run up to 13 kilometers per hour (8.1 miles per hour) for short distances. They tend to forage with a slow, lumbering manner using their sense of smell to find food. Young Tasmanian devils are more agile, however, and can climb trees.
Tasmanian devils are very good swimmers, however if they have young in the pouch, they avoid swimming for more than very short distances. Tasmanian devils actually love water and will wade and splash about, even sitting or lying down in it to stay cool. They will often dabble in water with their front paws, somewhat in the manner of raccoons. Tasmanian devils will sometimes store food in water and can even take a breath and “duck dive”.
Tasmanian devils are carnivorous hunters and mainly scavenge for their food, but will feed on whatever is available, either as carrion or prey. They take most of their large prey in the form of carrion.
Native animals, such as wombats, wallabies, and possums, are favorites, but they also feed on various small birds and mammals, such as sheep (Ovis aries), and rabbits. Seabird colonies, such as short-tailed shearwaters (Ardenna tenuirostris) or muttonbirds (Puffinus tenuirostris) were once thought to have traditionally been preferred by Tasmanian devils, providing an important food source. These colonies are now much reduced along the east coast with some sites remaining along the west coast. Carcasses of sheep and cattle (Bos taurus) provide food in farming areas. Other food items, such as insects, insect larvae, snakes, and small amounts of vegetation, are taken when encountered. Reptiles, amphibians, insects, and even sea squirts have been found in the stomachs of wild devils. Tasmanian devils may have even depended on carrion left from thylacine (Thylacinus cynocephalus) kills in historical times.
Tasmanian devils are efficient scavengers with powerful jaws and teeth that enable them to completely devour their prey, eating even bones and fur. They are famous for their rowdy communal feeding, which is accompanied by aggression and loud vocalizations.
The mating system of the Tasmanian devil is polygynandrous. Male Tasmanian devils compete for access to breeding females while females mate with multiple males in order to improve their chances of producing healthy offspring. There is no longer term association of males and females. Tasmanian devils are monestrous and breeding takes place within February and March with most mating taking place in March.
During the breeding season, a female will invite a male into her den to signal that she’s ready to mate. The male will drag the female into the den by the neck, but the female’s neck has thickened to protect her from the male’s vicious teeth. Once inside the den, the female will become completely submissive, appearing sedated and allowing the male to position her by the neck wherever he pleases. Unlike many other dasyurids, the Tasmanian devil’s marsupial pouch is completely closed when breeding.
Most Tasmanian devil young are born a month or two after mating, usually in April, after a gestation period of 21 days. Although a Tasmanian devil can give birth to up to 40 young, only a maximum of four can survive per litter because of the limited number of mammae in her pouch. Each female Tasmanian devil has four teats inside her pouch, so only the first four young that firmly attach to one will survive while the rest will starve. Although four Tasmanian devil pouch-young sometimes survive, the average number is two or three per litter. Because Tasmanian devils are marsupials, their young are born as external embryos, just the size of a grain of rice, and must find their own way into the mother’s pouch. Once in the pouch, they remain and continue developing for three-four months. The mother Tasmianian devil will nurse and protect the offspring in the pouch during most of their development.
At two weeks, ears begin to form on the embryos. At seven weeks, they begin to grow hair and fur. At around three months old, the young can open their eyes for the first time and emerge from the mother’s pouch. At this time, they are left in a simple den. By five-six months old, usually around late December, the young are completely weaned and able to become independent and disperse from their natal range and out into the bush. Tasmanian devils probably become sexually mature and start breeding at the end of their second year. Most young die immediately after dispersing out of their natal range as a result of food scarcity or competition.
The value of Tasmanian devils as important members of functioning ecosystems and as scavengers probably outweighs any negative effect of these animals on humans. Tasmanian devils are important top, apex predators in native, Tasmanian ecosystems. As scavengers, they are important in removing carcasses, maintaining bush and farm hygiene by cleaning them up. This can help reduce the risk of blowfly strike to sheep (Ovis aries) by removing food for maggots.
Adult Tasmanian devils have few natural predators, although Thylacines (Thylacinus cynocephalus) may have preyed on them occasionally. Small Tasmanian devils may fall prey to eagles (Accipitridae), owls (Strigiformes), and spotted-tailed quolls (Dasyurus maculatus). Their nocturnal activity may help them avoid some predators, such as thylacines, historically.
Each year, reports estimate about 50 Tasmanian devils killed by poorly controlled dogs. These reports tend to come from about 20 different dog owners, in which there is no obligation or incentive for such reports. This, combined with general hesitance in reporting Tasmanian devil deaths, suggest that the real figures are probably more close to several hundred devils killed by dogs each year.
There have been spasmodic, small-scale introductions of the red fox (Vulpes vulpes) into Tasmania since early European colonization. Early incursions were sometimes efforts at acclimatization and others for short-term hunting. More recently, there has been at least one accidental incursion, from a container ship in 1998, and credible reports of a concerted, malicious campaign of introduction. Hard evidence, such as confirmed scats and carcasses of foxes, has been found in the north-west and northern and southern midlands. Credible sighting reports have come from most of the eastern half of the State including the central highlands and the far north-west, mostly areas where Tasmanian devil populations are suppressed by DFTD. It is possible that foxes have been present in Tasmania for many decades at sub-detectable levels, and that a degree of ecological release has occurred due to DFTD, with foxes increasing to detectable numbers. Based on modelling of habitat preferences and densities in south-east mainland Australia, Tasmania has the potential to hold up to 250,000 foxes, which could replace most medium- to large-sized marsupial carnivores.
A commonly held view has been that the abundance of Tasmanian devils has prevented fox establishment through interference competition, either aggressive exclusion or predation on denned juveniles. Red foxes and Tasmanian devils share preferences for den sites and habitat and are of a similar size. As such, Tasmanian devils abundance is likely to slow, if not prevent, fox establishment. The current impact of the Red fox has been quantified and it is unlikely that fox numbers are currently at a level to impose a measurable impact. A decline in Tasmanian devil numbers may create a short- to medium-term surplus of food, such as carrion, ideal for fox establishment.
Fox establishment may cause both direct and indirect effects on Tasmanian devils. Direct effects include reciprocal killing by foxes of juvenile devils at dens while the female forages. Fox establishment may also cause ecosystem disruptions through changes in other species, a feature of foxes on mainland Australia and something that might then also indirectly affect Tasmanian devils.
Today, the Tasmanian devil is a Tasmanian icon, but they were once considered nuisance animals by early European settlers of Hobart Town who complained of raids on poultry yards.
In 1830, the Van Diemen’s Land Company introduced a bounty scheme to remove Tasmanian devils, as well as thylacines and wild dogs, from their northwest properties. They offered 2/6 (25 cents) for male devils and 3/6 (35 cents) for females. For more than a century, Tasmanian devils were trapped and poisoned. They became very rare, seemingly headed for extinction, but the population gradually increased after they were protected by law in June 1941. Populations stabilized and may have also increased due to the increased availability of carrion in rangelands.
Tasmanian devils have also been considered livestock predators, especially on animals such as sheep. Although this is unlikely, they have been known to kill poultry. In reality, these carnivorous marsupials take most of their large prey in the form of carrion.
Tasmanian devils are now protected wholly in Tasmania, but if this apex predator does become extinct, all wildlife in Tasmania will be affected.
In May 2009, the Federal Government up-listed the Tasmanian devil to the Endangered category under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999. The Tasmanian devil’s status was formally upgraded to Endangered under Tasmania’s Threatened Species Protection Act 1995 in May 2008. In late 2008, the Tasmanian devil was also up-listed to Endangered on the International Union for the Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species – widely considered the most authoritative system for classifying species in terms of their risk of extinction.
Traditionally their numbers were controlled by food availability, competition with other devils and quolls, loss of habitat, persecution and vehicular strike, but the greatest recent threat to devils across Tasmania is the Devil Facial Tumor Disease (DFTD).
The greatest recent threat to Tasmanian devils across Tasmania is Devil Facial Tumor Disease (DFTD).
In 1996, many populations of Tasmanian devils were first recorded to be devastated by a new, usually lethal, cancer-like disease called Devil Facial Tumor Disease that was spreading rapidly throughout Tasmania. This transferrable cancer had a female origin and evolved different strains to quickly spread throughout the state. In 2014, a second type of DFTD was first recorded in the Channel area, this time having male origination. There is some evidence that this disease is not new, but it is endemic to Tasmanian devils. Historical record and epidemiological modeling suggest that this epidemic may cycle through Tasmanian devil populations at 77-146 year intervals. Today, nearly all devils of mating age or over are infected.
While there are differences between the two types of cancer, both DFTD 1 and 2 are contagious and fatal. Once infected, devils usually die within a few months of the cancer becoming visible. The tumors are first noticed in and around the mouth as small lesions or lumps, then develop into large tumors around the face and neck and sometimes even in other parts of the body. Badly affected devils have many tumors throughout the body. Sometimes, the tumors grow inside the mouth and push out the teeth, making it difficult for the devil to eat. The live tumor cells aren’t rejected by the devil’s immune system because of the cancer’s ability to hide from the immune system. Death results from starvation and the breakdown of organs and body functions as a result of the cancer.
Devil Facial Tumor Disease is extremely unusual as it is only one of six recorded cancers than can spread like a contagious disease. Currently, we know of transmissible cancers spreading through natural animal populations in seven species across vertebrate and invertebrate organisms and in both terrestrial and marine ecosystems. It is expected further study will likely uncover more examples. Of the known transmissible cancers, two are found in Tasmanian devils, three in five different species of bivalves, and one in dogs.
Devil Facial Tumor Disease (DFTD) is passed from Tasmanian devil to Tasmanian devil through physical contact, including biting associated with copulation and fighting. Because this transferrable cancer is passed through biting, it is mostly passed on during the breeding season.
In diseased areas, nearly all sexually mature Tasmanian devils, older than two years of age, become infected and succumb to the disease. Juveniles as young as one year old can also be infected. This is resulting in populations with a very young age-structure in which females have only one breeding event, whereas they would normally have three. Populations in which DFTD has been observed for several years have declined by up to 80% (approximate, due to low sample size in recent years). There is no evidence to date of the decline in devils stopping or the prevalence of the disease decreasing, but monitoring teams continue to assess Tasmanian devil populations as DFTD spreads.
Although this disease has not resulted in extinction in the past, the effect of additional, human-associated threats may pose a grave threat to the persistence of Tasmanian devil populations. There’s a real fear that Tasmanian devils could become extinct. The identification of a second type of DFTD highlights the importance of ongoing monitoring of wild populations and disease investigations as part of assisting the ongoing survival of the Tasmanian devil in the wild.
Tasmanian devils are now protected wholly in Tasmania. In September 2006, the Tasmanian devil disease was gazetted under the Animal Health Act as a List B notifiable disease.
At the end of 2003, the Tasmanian State Government’s Department of Primary Industries, Water and Environment (now Department of Primary Industries and Water) launched the Tasmanian Devil Disease Program to investigate and respond to the threat of Devil Facial Tumor Disease. This program, now called the Save the Tasmanian Devil Program, has attracted many collaborative researchers. A forum exclusive to those directly involved in DFTD research in February 2007 was attended by approximately 80 people. The mission of the Save the Tasmanian Devil Program is “to maintain the Tasmanian Devil as an ecologically functional species in the wild”.
Conservation actions, including research directed towards improving conservation management, are driven by three future scenarios that have the potential to turn the epidemic around and bring devils back into the landscape as an ecologically functional species. These are extinction in the wild and reintroduction, the evolution of resistance, and the broad-scale application of a vaccine. Four management actions can therefore potentially be employed: establishing insurance populations; disease suppression in wild populations; selection for disease resistance; and development of a vaccine. Each of these is included in the current Strategic Plan of the Save the Tasmanian Devil Program.
The highest priority is to establish insurance populations of healthy devils in places isolated from the disease, firstly to avoid total extinction and, secondly, as a source for reintroduction to the wild if devils, and therefore also the disease, become extinct. Because these populations will possibly carry the species for 25-50 years and because devils already have low genetic diversity, a conservative retention of genetic diversity of 95% is recommended. A large founder base of 150 individuals is recommended to be built up to an effective population size of 500 individuals. This would mean maintaining an actual population size of about 1700 individuals, if they were all maintained in captivity where breeding is closely managed, or 5,000 individuals if they were all wild-living.
Insurance populations would ideally be managed as a metapopulation of multiple captive and wild populations with managed migration between populations to maintain genetic diversity. Maintenance of wild, as well as captive, insurance populations is important because wild-living animals retain natural behaviors and natural suites of parasites, pathogens and commensals, all of which are progressively lost in captive animals. The options for wild insurance populations are offshore islands, and fenced enclosures on mainland Australia and disease free areas on mainland Tasmania. There are a number of issues to be considered with these possible types of insurance populations, including the number of potential sites, the number of devils that could be held, balancing the conservation value of the sites for other purposes, ecological functionality, biosecurity risk, whether the site is currently disease-free or whether disease eradication would be required, cost of establishment and maintenance, stakeholders and timescale.
To date, there have been three intakes of founders for captive insurance populations from the wild: 26 devils from eastern and north-western genetic provenances in 2005, 25 north-western founders in 2007, and 63 north-western founders in 2008. Founders were collected from as wide a geographic area, as assurity of disease-free status permitted at the time, established though intensive and extensive surveys and including a buffer zone. This intake area gets smaller each year as DFTD spreads and is currently the north-west corner and a strip down the west coast. Founder devils were accepted for collection according to a strict set of protocols: recently weaned and likely to be predispersal, no biting injuries and no signs of sexual maturity/oestrus in females. The first two intakes were maintained in quarantine in Tasmania for 20 months and 8 months, respectively, in facilities where there were no wild devils on the outside (suburban, island). The current intake will be maintained in quarantine for a shorter period. Afterward, these founder devils are transferred to mainland zoos where they are managed by the Australasian Regional Association of Zoological Parks and Aquariums (ARAZPA).