Dasyurus

Quolls (; genus ''Dasyurus'') are carnivorous marsupials native to Australia and New Guinea. They are primarily nocturnal and spend most of the day in a den. Of the six species of quoll, four are found in Australia and two in New Guinea. Another two species are known from fossil remains in Pliocene deposits in Queensland. Genetic evidence indicates that quolls evolved around 15 million years ago in the Miocene, and that the ancestors of the six species had all diverged by around four million years ago. The six species vary in weight and size, from to . They have brown or black fur and pink noses. They are largely solitary, but come together for a few social interactions such as mating which occurs during the winter season. A female gives birth to up to 18 pups, of which only six survive because she only has six teats with which to feed them. They have a life span from 2 to 4 years.

Quolls eat smaller mammals, small birds, lizards, and insects. All species have drastically declined in numbers since Australasia was colonised by Europeans, with one species, the eastern quoll, becoming extinct on the Australian mainland, now found only in Tasmania. Major threats to their survival include the toxic cane toad, predators such as feral cats and foxes, urban development, and poison baiting. Conservation efforts include breeding programs in captivity, one of which is taking place in Tasmania with support from Rewilding Australia and Conjour.

Taxonomy

The name ''Dasyurus'' (from Greek δασύουρος, ''dasyouros'') means "hairy-tail", and was coined by Étienne Geoffroy Saint-Hilaire in 1796.

In 1770, Captain Cook collected quolls on his exploration of the east coast of Australia, adopting an Aboriginal name for the animals. Although the origin of Cook's specimens are unclear, the word and its variants ''je-quoll'', ''jaquol'' or ''taquol'' are derived from the word '' dhigul'' in the language of the Guugu Yimithirr people of far north Queensland. No evidence indicates the local indigenous people used the word in the Sydney area. They were likened in appearance to a polecat or marten in the earliest reports, the tiger quoll being called "spotted marten" and eastern quoll "spotted opossum", but by 1804, the names "native fox", "native cat" and "tiger cat" had been adopted by early settlers; quolls are still called "marsupial foxes" or "marsupial cats".

In the 1960s, noted naturalist David Fleay pushed for the revival of the term "quoll" to replace the then-current vernacular names that he felt were misleading. They are very well known animals in Australia.

Four species have been recovered from Pleistocene cave deposits from Mount Etna Caves National Park near Rockhampton in central Queensland. Remains of the tiger quoll and the northern quoll, and a species either identical or very similar to the eastern quoll, as well as a prehistoric species as yet undescribed, all lived in what was a rainforest climate. The northern quoll is still found in the region. The fossil species ''D. dunmalli'', described by Bartholomai in 1971, is the oldest species recovered to date. Its remains were found in Pliocene in southeastern Queensland. Known only from a lower jaw and some teeth, it was a relative of the tiger quoll.

The first species described, the eastern quoll, was originally placed in the American opossum genus '' Didelphis'' by an anonymous author, and named ''Didelphis maculata''. This name is no longer considered valid, and the second part of the name is now given to a different species, the tiger quoll, ''Dasyurus maculatus'', while the eastern quoll was renamed ''Dasyurus viverrinus'' by George Shaw in 1800.

The tribe Dasyurini, to which quolls belong, also includes the Tasmanian devil, the antechinus, the kowari, and the mulgara. Genetic analysis of cytochrome b DNA and 12S rRNA
of the mitochondria indicates the quolls evolved and diversified in the late Miocene between 15 and 5 million years ago, a time of great diversification in marsupials. The ancestors of all current species had diverged by the early Pliocene, around 4 million years ago.

The genus ''Dasyurus'' consists of six species of quoll:
*The bronze quoll (''D. spartacus'') is the only mammal found in the Trans-Fly ecoregion, but not in northern Australia. It is found in the southern part of New Guinea south of the Fly River. Rising sea levels due to an increase in global temperature caused a land bridge that once connected Australia and New Guinea to be covered up with water. A 2007 study conducted by the University of New South Wales suggests the bronze quoll is closely related to the western quoll, their ancestors diverging with the separation of land masses.
*The western quoll or ''chuditch'' (''Dasyurus geoffroii'') is restricted to the Jarrah Forest and the central and southern Australian Wheatbelt. The western quoll is believed to have once occupied 70% of Australia, but because of cane toads, predators, habitat destruction, and poison baiting, it is now less abundant.
*The New Guinean quoll (''Dasyurus albopunctatus'') is found throughout most of New Guinea. It tends to live at an elevation of about , and is not found in the south-western lowlands, although it can found on Yapen Island.
*The eastern quoll (''Dasyurus viverrinus'') is now considered extinct on mainland Australia; the last sighting there was in the 1960s, but it does inhabit much of nearby Tasmania, where it can be found in rainforests, heathland, alpine areas, and scrubs. It can be found near farms, as it eats pasture food. The eastern quoll can also be seen in the Mount Field National Park.
*The tiger quoll or spotted-tail quoll (''Dasyurus maculatus''), lives in south-eastern Australia. It tends to prefer rock dens more than dens made out of wood. In a study submitted by Belcher and Darrant in 2006, the habitats of tiger quoll were directly related to the amount of prey found in the area. Gullies and drainage ditches were used quite often by the quolls, and ridges with rocky outcrops were used to make the rock dens the animals enjoy. The species in Queensland has declined rapidly and is now absent from the Brisbane region. Important strongholds for the population occur in the Blackall/Conondale ranges, Main Range, Lamington Plateau and the McPherson and Border ranges.
*The northern quoll (''Dasyurus hallucatus'') could be found in the northern third of Australia a century ago. Presently, it resides in high rocky areas and areas with heavy rainfall. It is abundant on the minor islands surrounding northern Australia. In 2003, northern quolls were translocated to Astell and Pobassoo Islands to isolate them from the toxic invasive cane toad. Genetic analysis indicates it is the earliest offshoot from the ancestors of other quolls.

The following is a phylogenetic tree based on mitochondrial genome sequences:

Description

Adults are between long, with hairy tails about long. Females have six nipples and develop a pouch during the breeding season, which opens toward the tail (with the exception of the tiger quoll, which has a true pouch) when they are rearing young. Their coats are brown or black, with a sparse scattering of white spots. They have bright pink noses and long snouts. Their natural lifespans are between two and five years; the larger species tend to live longer than the smaller. Quolls are solitary, nocturnal animals. The average weight differs greatly depending on the species; male western and eastern quolls weigh about and females . The tiger quoll is the largest, with the male weighing about and the female . The northern quoll is the smallest, and the male weighs on average , and the female .

Distribution and habitat

Quolls are indigenous to mainland Australia, New Guinea, and Tasmania. The six species were once widely distributed across the three land masses, but are now restricted to only a few areas. Although primarily ground-dwelling, the genus has developed secondary arboreal characteristics. Each species of quoll lives in distinct geographical areas. The tiger quoll and eastern quoll are exclusively mesic zone species, that is they inhabit moister habitats. The western quoll also inhabits mesic habitat, but has adapted to arid regions across inland Australia, while the northern quoll inhabits tropical habitat of high rainfall.

Behaviour

Quolls are carnivorous marsupials. They are primarily nocturnal, sleeping in hollowed-out logs or rocky dens and coming out to hunt during the night, though on rare occasions they can be seen looking for prey during the day.

They are mostly ground-dwelling, but it is not uncommon to see a quoll climbing a tree. Quolls mark their territory several kilometres away from their dens. A male's territory often overlaps many females' territories, and male and female quolls only meet for mating. Quolls have communal toilet areas, usually on an outcropping used for marking territory and social functions. These communal latrines may have up to 100 droppings in them.
Quolls are mostly solitary creatures, limiting contact with other quolls to mating or other social activities.

Diet

Quolls are mostly carnivorous. The smaller quolls primarily eat insects, birds, frogs, lizards and fruit; the larger species eat birds, reptiles, and mammals, including echidnas and possums. The tiger quoll's diet is dominated by mammals such as brushtail possums, rabbits, hares and invertabrates. The exact mix is variable depending on the availability of prey after bushfires, and can include carrion or bandicoots when food is scarce. The other species of quoll have also been known to eat carrion. The paws and vibrissae of quolls allow them to reach into small burrows to find prey. Quolls hunt by stalking. Depending on the size of its prey, a quoll may leap or pounce on it. Quolls pin small prey down with their front paws while devouring it, and jump onto larger prey, sinking in their claws and closing their jaws around the neck. Quolls can obtain all the water they need from their food, making them quite adaptable during droughts or other periods of water shortage. A study of historical records revealed 111 written accounts of quolls opportunistically feeding on human remains in Australia.

Reproduction

Mating occurs during the winter months. Once a female quoll has been impregnated, the folds on her abdomen convert into a pouch that opens at the back. The gestation period is 21 days. A baby quoll, or pup, is the size of a grain of rice. Up to 18 quolls are born in each litter, but only six survive the first two weeks. The survivors stay in their mother's pouch for eight weeks, suckling on one of the mother's six teats for milk. During the ninth week, the pups venture out of the pouch and onto the mother's back, where they remain for six weeks. Quolls reach maturity when they are one year old, and have a natural lifespan of between two and five years. A 2008 study of the pouches of tiger quolls reported the pouches' appearance were reliable indicators of the quolls' reproductive status: during the follicular phase, pouches were found to be red and have many secretions. After ovulation, pouches became deep and wet. Researchers can use this information to determine where a female quoll is in her ovarian cycle, which is anticipated to be helpful in breeding management.

Threats

Cane toads were introduced into Queensland in 1935; their numbers have since grown exponentially. These poisonous toads pose a significant threat to the northern quoll, which may die after consuming one. The Department of Sustainability, Environment, Water, Population and Communities has stated that cane toads are highly invasive and are major threats to the survival of quolls.

Predators such as foxes and cats prey on quolls and compete with them for food. For example, both quolls and foxes catch and consume rabbits. Since the introduction of foxes, quoll populations have dropped dramatically. Foxes have been eradicated from many of the islands off the coast of Australia in an effort to protect quolls.

Quolls are suffering badly from urbanisation, housing development, mining development, and expansion of agricultural lands. Habitats are also being destroyed by large herbivores trampling the grass and overgrowth, making camouflage difficult. Bush fires and weeds also contribute to habitat destruction.

The natural poison fluoroacetate (Compound 1080) is commonly used in Australia to control introduced pests such as European rabbits, foxes, feral predators, and wild dogs such as dingoes. The poison is extremely toxic to introduced pests, but less so to native animals as it is found naturally in many Australian plants. However, juvenile quolls may be susceptible to the poison. Research is underway to determine whether the number of quolls protected from predators may be less than those killed by the poison.

Conservation efforts

Since 1770, all Australian quoll species have declined in number owing to habitat loss caused by urbanisation. Rabbits were introduced to Australia with the arrival of the First Fleet in 1788 as part of biodiversity enrichment efforts. The native quolls predated upon rabbits and prior to 1870, many accounts recorded quolls impeding their establishment on the mainland while island colonies thrived. Quolls were systematically exterminated by colonists to defend introduced species such as chickens; rabbits populations subsequently reached plague proportions.

The northern quoll is threatened by toxic cane toads, but a University of Sydney project revealed in 2010 is teaching them to avoid eating the invasive amphibians.
In 2008, the Northern Territory Wildlife Park in Australia recorded their first litter of quoll pups in the park. The quolls bred well in captivity, with over 15 litters in the 2008 breeding season alone.

In late October 2011, a litter of five tiger quoll pups was born at Wild Life Sydney in Darling Harbour, Australia. The pups were born to inexperienced parents, both just one year old. The reason for the young parents was because older male quolls can become violent and kill the female if they do not want to mate. By breeding one-year-old quolls, there was no threat of violence. Four of the quoll pups will be sent to other zoos or wildlife parks across Australia, but one, which the researchers named Nelson, will stay at the centre to become an "ambassador for all quolls".

Fox control programs have benefited the western quoll. The Department of Environment and Conservation (Western Australia) monitors western quoll populations in the Jarrah Forest as part of its faunal management programs, as well as ongoing research into fox control, timber harvesting, and prescribed burning. The Perth Zoo has been monitoring a successful captive-breeding program since 1989. It has successfully bred more than 60 western quolls, most of which it transferred to Julimar Conservation Park, with proposals to translocate to Wheatbelt reserves and Shark Bay.

The bronze quoll occurs in a few protected areas, such as Wasur National Park and Tonda Wildlife Management Area. More research on distribution and threats is needed for further conservation.

Creating a native pet industry in Australia related to quolls could aid in their conservation. However, concerns exist about this methodology in regards to animal husbandry, conservation benefits, and other issues. Some scientists believe that keeping quolls as pets could aid in their long-term conservation, but further research is needed on this topic to conclude whether this is true or false.

Bristol Zoo is the first zoo in the UK to successfully breed quolls.

In March 2018, twenty eastern quolls bred in a wildlife park in Tasmania were released into the Booderee National Park on the NSW South Coast. After 50 years of absence, the effort to reintroduce eastern quolls to mainland Australia achieved success, with 15 babies found in the pouches of three adult females.

In May 2021, the re-introduction of Quolls to Booderee National Park has been reported to have failed when numbers were down to one male.

Quolls have been studied in captivity, with the ultimate aim of supporting conservation of the species, and future translocations. These studies include investigations into their haematology and blood biochemistry profiles, and dietary studies.Stannard HJ, Old JM (2013). Digestibility of two diets by captive eastern quolls. Zoo Biology. 32, 417-422. DOI: 10.1002/zoo.21073

Culture contexts

Tjilpa is the name given to the quoll amongst the Northern Arrernte language group of Australian Aboriginal people.

References

Bibliography

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External links

Bush Heritage Australia: Quolls

{{Taxonbar, from=Q379740

Dasyuromorphs
Marsupials of Australia
Marsupials of New Guinea
Extant Miocene first appearances
Taxa named by Étienne Geoffroy Saint-Hilaire