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Episode 315: Carnivorous Quolls

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The Eastern quoll (image from www.examiner.com.au)

The Northern quoll (image from www.nature.com)

The Western Quoll (image from www.mammalage.com)

The spotted tail quoll (image from http://www.cfzaustralia.com)

Australia is famous for their marsupials, but one of the arguably lesser known marsupials is the quoll, a small carnivorous spotted animal that was once widespread throughout the continent. There are 4 species currently:

  • The Western Quoll (Dasyurus geoffroii)
  • The Eastern Quoll (Dasyurus viverrinus)
  • The Northern Quoll (Dasyurus hallucatus)
  • The Spotted Tail Quoll (Dasyurus maculatus)

Aside from dingoes, the quolls are the largest carnivore left in mainland Australia. Reaching a maximum of 125cm, quolls roam throughout coastal heathlands, temperate woodlands, forests and riparian forests, preying on insects, small reptiles, bird eggs, small birds, up to larger mammals like rabbits and possums. This makes them very important for ecosystem balance, as they can prey on invasive and troublesome rats, mice and rabbits. They may be small, but quolls need to pack a punch to hunt their prey. They have an incredibly high bite force, in fact the second highest bite force of any predatory mammal, coming in just behind Australia’s very own Tasmanian Devil.

Toxic toads and shrinking homes: the threats facing quolls

Australia has the highest mammal extinction rate in the world, and unfortunately the quoll has brushed close to this fate itself. Before European settlement of the continent, all species of the quoll were widespread across the continent. Today, they are confined to smaller pockets, with the Eastern and Northern Quoll classed as endangered and the Spotted and Western Quolls determined to be near threatened by the IUCN. Habitat destruction and fragmentation has pushed the species into this smaller, isolated areas, especially as timber harvesting has increased in Australia to meet growing demand for wood.

An example of the range contraction facing the quoll. The yellow shows the previous distribution of the endangered Northern Quoll and the orange shows their range today after loss of habitat due to forest clearance (image from wildlife.org.au)

Like so many small mammals in Australia, quolls are massively affected by feral and invasive species like cats, dogs, goats and foxes. Some species, like foxes and dogs, will outcompete quolls for food, as much of their diet overlaps, although research does show that quolls preferentially hunt in forested areas, whereas foxes and dogs prefer more urbanised areas. As forests shrink, quolls are left with less resources, leading to competition within the species. This can lead them to forage in more urban areas likes campsites, where they are at risk from attacks by domestic dogs or collisions with cars. They are also frequently preyed upon by feral cats. In many areas, poison baits are distributed throughout habitats to reduce numbers of feral foxes, cats and rabbits, which is an unfortunate but necessary control tactic. Often quolls will accidentally ingest some of these baits, and although most are made with natural toxins from plants that many quolls are resistant to, juvenile quolls are particularly vulnerable to these poisons.

Although livestock don’t pose a direct threat to quolls, there will overgraze vital vegetation which the small marsupials use to hide from predators like the dingo. And despite the fact that dingoes sometimes prey on quolls, they are surprisingly linked in another way. In areas where dingoes are being eradicated, smaller, secondary predators, called mesopredators, are being freed from predation to hunt and kill quolls in higher numbers than regions where dingo populations are left alone. If you want to learn more about dingoes and the controversy that surrounds their role in the outback, checkout episode 243, Down Under With Dingoes.

Quolls are also affected by that amphibian scourge of Australia, the cane toad. Introduced in 1935 by s research station to control cane beetles and other pests, the toads quickly got out of control and spread, undergoing enormous population expansions and devastating all manner of native wildlife. Without any native predators, the toads are out of control. They excrete a potent defensive toxin, which is a particular problem for the quolls, who try to take cane toads for dinner, poisoning themselves in the process. In quoll areas that have been reached by cane toads, there have been some serious declines in the little marsupials, although there is evidence now that some species, like the Northern Quoll, are learning to avoid them. In these areas, it seems quolls and toads co-exist, without serious poisoning mortalities. For those quolls who aren’t so savvy, researchers are using minced cane toad sausages laced with a chemical that makes them feel nauseous. Eventually, up to 68% of the quolls in the experiment learned to avoid the unpleasant sausage snack, and hopefully they won’t fancy a bite of cane toad if they come across the hopping menaces in their foraging.

The invasive cane toad has become a scourge on Australia’s wildlife (image from insider.si.edu)

Like so many species in Australia, there are big concerns over extreme weather events and how they might affect the quolls. Fortunately, there are few records of direct mortalities from forest fires, such as is seen with koala bears, but they can suffer from the habitat disruption caused by such extreme events, and the stress of fleeing the fires can cause delays in breeding. In 2001-2003, harsh summers led to marked declines of the Eastern Quoll in some regions, and these populations have still not recovered to this day.

Conservation Optimism

Bush Heritage Australia are a conservation organisation working to preserve habitat across the continent, protecting the species that species that live within them, including all four species of quolls, which are all present on BHA protected land. They also have two very special employees; two quoll trained sniffer dogs that keep a nose out for the quolls so that researchers can track their movements and habitat use. They also run feral predator eradication programmes, sadly having to use poison baits to keep numbers low enough for quolls to live safely. To prevent having to kill animals to save others, they also raise awareness of the dangers of invasive animals, encouraging people to sterilise their pets. If you’re reading this from Australia and you have a beloved cat, maybe consider keeping them indoors a little more, providing them with a catio for outside space or leash training them, so they can get out for some fresh air and you can protect wildlife, all in one!

The BHA also have camera traps set up across large areas, which they use to monitor populations and carry out important research into these small, shy marsupials. Like most conservation schemes, habitat protection and restoration is vital, and they maintain native vegetation like the vital hollow logs quolls use to sleep in, as well as developing artificial habitat features in more urbanised areas. You can learn more about their work at Healthy Country Protected Forever – Bush Heritage Australia.

A spotted tail quoll being released into the Tasmanian midlands by staff and volunteers from Bush Heritage Australia (image from www.bushheritage.org)

The Australian Quoll Conservancy is another conservation charity focused specifically on the plight of the quolls who work closely with the Australian government to continue the development of a National Recovery Plan. They have been involved in a lot of long term research, and have developed guidelines for best husbandry practices for weighing, sexing, identifying individuals and determining breeding status in ways that cause the least stress possible for the animals. They have a specialized Species Recovery Unit, a team of professionals, volunteers and business owners that conduct surveys of quolls, travelling out into the wilds to record their numbers and health status. This is vital work so that policy can protect the most important habitats. Check them out at Page 1 (quolls.org.au).

Populations of the Northern Quoll have been moved to offshore islands where there have been some great success stories, including Pabassoo and Astell Island. On these isolated islands it is much easier to control invasive species than on the mainland.

Like many species facing an uncertain future, they are many captive quolls in zoos and organisations all over the world that are ensuring populations  for reintroduction in case of any future catastrophes.  At animal park Wild Life Sydney, there is a famous spotted tail quoll called Nelson, who has fathered many pups that have been released into the wild, and who now acts as an ambassador for his species. A little quoll celebrity! Since 1989, Perth Zoo has run a breeding programme for the Western Quoll, which has bred 60 healthy quolls. If you’re in Australia, you’re unlikely to spot these elusive marsupials in the wild, so why not take a trip to one of these zoos and check these adorable Australian critters in the flesh!

An Eastern Quoll in captivity in Leipzig zoo (image from ww.zoo-leipzig.de)

Awesome videos!


Attard, M.R.G. Chamoli, U. Ferrara, T.L. Rogers and Wroe, S. (2011) ‘Skull mechanics and implications for feeding behaviour in a large marsupial carnivore guild: the thylacine, Tasmanian devil and spotted-tail quoll.’ Journal of Zoology

Fancourt, B.A. Bateman, B.L. VanDerWal, J. Nicol, S.C. Hawkins, C.E. Jones, M.E. and Johnson, C.N. (2015) ‘Testing the role of climate change in species decline: is the Eastern Quoll a victim of a change in the weather?’ PLOS ONE

Glen, A.S. and Dickman, C.R. (2008) ‘Niche overlap between marsupial and eutherian carnivores: does competition threaten the endangered spotted-tail quoll?’ Journal of Applied Ecology

Hernandez-Santin, L. Goldizen, A.W. and Fisher, D.O. (2016) ‘Introduced predators and habitat structure influence range contraction of an endangered native predator, the northern quoll.’ Biological Conservation

Moore, H.A. Dunlop, J.A. Jolly, J.C. Kelly, E. Woinarksi, J.C.Z. Ritchie, E.G. Burnett, S. van Leeuwen, S. Valentine, L.E. Cowan, M.A. and Nimmo, D.G. (2022) ‘A brief history of the northern quoll: a systematic review.’ Australian Mammalogy.



January 18, 2023
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