Setonix brachyurus

Geographic Range

On the southwestern coast of Western Australia, several isolated mainland populations of Setonix brachyurus reside in areas with 1000 mm or more annual rainfall in Nature Reserves and National Parks. With global climate change and exotic predators such as foxes and cats, this population range is contracting. The adjacent islands of Rottnest Island and Bald Island do not have these predators and are home to larger populations.

• Biogeographic Regions
• australian australian
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Agonis is a plant that is endemic to southwest Australia, especially found in the northern jarrah forest. Setonix brachyurus is specialized to this Agonis swamp habitat with dense vegetation. Swampy vegetation provides protection for quokkas on the mainland from their predators. Plants such as Gahnia trifida provide refuge for this species on hot days on Rottnest Island. Due to their sumptuous need for water, these animals must reside close to freshwater. Quokkas gravitate towards these scrubland habitats in their early stages after a fire. Approximately ten to nineteen years postfire, new growth provides a higher nutrient content for Setonix brachyurus as well as other macropods. After this crucial time, quokkas are likely to disperse in search of a new habitat; however this is difficult on the mainland with their predator Vulpes vulpes . Since they stay in the same place year-round, quokkas are able to cope with seasonal changes, including semi-arid habitats on Rottnest Island.

• Habitat Regions
• temperate temperate

• Terrestrial Biomes
• forest forest
• scrub forest scrub forest

• Wetlands
• swamp swamp

Physical Description

Setonix brachyurus is among the smallest wallabies and is commonly referred to as the quokka. This species is the only member in its genus. They are similar in appearance to other marsupials such as Petrogale and Macropus giganteus , which have a pouch for carrying their young. However, they have a relatively shorter tail which is 25 to 30 cm. They have coarse, bushy brown fur with a lighter underbelly, and strong hind legs. They have a small head with a naked, black nose and round ears. Quokkas have a large, hunched back and very short arms in front. Males weigh between 2.7 and 4.2 kg and are slightly larger than females who weigh between 1.6 and 3.5 kg.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

Reproduction

It is typically the female quokkas who choose which male they mate with. If she rejects the male, she will run away and he will move on to another. If the female reciprocates, she will stay with the male and groom him, signalling that she is interested in reproducing. Larger, heavier males are more dominant in the Setonix brachyurus social hierarchy. A dominant male will usually fight a subordinate male for a female. Only after a male has mated with a female will he defend her. This pair will usually spend two breeding seasons together; although, females have one to three partners while males keep one to five. The social structure is different between female and male quokkas. Females tend to avoid with each other, whereas males occasionally come into contact over a female and form a hierarchy based on weight/size.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Peak breeding season for Setonix brachyurus occurs between January and March when the weather is cooler. Females produces one offspring. The gestation period is approximately one month, and after birth the joey moves to its mother’s pouch. This is where it stays for six months for protection and food until it is weaned off and begins to explore for itself. Sexual maturity occurs around ten to twelve months. After giving birth, the mother mates again and embryonic diapause occurs. This new embryo remains dormant for approximately five months, when the body can detect if the first joey had survived or not. If the young dies, the embryo implants and develops, and if the joey is alive, the embryo disintegrates.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• embryonic diapause embryonic diapause

Once a female gives birth to a joey, she carries it around in her pouch for about six months to provide protection and nutrition. The young joey suckles her milk, and after six months will stay close to the mother for protection and milk. Males provide no parental care although he will usually defend a female that is pregnant with his offspring.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • female
• pre-independence
  • provisioning
    • female

Lifespan/Longevity

Quokkas live about 10 years in the wild and up to 14 years in captivity.

Behavior

On the mainland, quokkas live in smaller colonies. Their family group consists of one to two dozen individuals. On Rottnest Island, they live in much larger groups of up to 150 individuals. Although these animals live in family units, they are not particularly social. Due to limited resources and predation on the mainland, quokkas appear to come together around resources such as fresh water, food and shelter. Especially during the dry season, quokkas tend to expand their living area and feeding environments in order to be closer to freshwater. This species is nocturnal, feeding at night and resting during the day, sheltered from the heat. Quokkas return to the same shelter day to day and dominant males will occasionally fight other males for shelter. The social hierarchy of males is correlated with size, with larger males more dominant. Setonix brachyurus has thick, strong hind legs that allow them to efficiently hop through grasses and climb in order to find food.

• Key Behaviors
• nocturnal nocturnal
• motile motile
• social social

Home Range

These populations have average home ranges of 6.39 hectares.

Communication and Perception

There is little information available on the communication and perception of Setonix brachyurus . Their sense of color vision is developed selectively among marsupials. Unlike wallabies, quokkas have color vision. This is likely to help the species spot their predators.

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

On Rottnest Island, Setonix brachyurus comes out at night to forage. Depending on the season, adult male quokkas will eat an average of 32 to 45 grams of dry food each day. The majority of their herbivore diet comprises of plants including succulents, shrubs, forbs, grasses and sedges. These leaves contain water so quokkas do not need to drink a lot throughout the year. They will also eat seeds, berries and other fruit if available. The can climb trees up to a meter and a half to forage. Quokkas do not chew their food, but rather they swallow it, regurgitate it and chew the cud.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore
  • granivore granivore

Predation

The mainland populations are threatened by the introduced European red fox Vulpes vulpes . Also, these animals are prey to domesticated cats and dogs, as well as wild birds of prey and dingoes. Since the introduction of their predators to Australia, quokkas have been shrinking in number. The island populations are free of these predators.

Ecosystem Roles

Quokkas have the role of prey to their predators mentioned above. They exhibit the effects of parasitism, particularly in summer when they have poor food resources and their digestive tracts are susceptible to infections such as Salmonella.

Economic Importance for Humans: Positive

The quokka is often referred to as “the happiest animal in the world” by humans. They are very friendly and are a big tourist attraction. Frequently the focus of pictures, these animals often look as though they are smiling at the camera. Due to their fragile population size, they cannot be taken in as pets.

• Positive Impacts
• ecotourism ecotourism

Economic Importance for Humans: Negative

There are no known adverse effects of Setonix brachyurus on humans.

Conservation Status

On the mainland, the introduction of their predators Vulpes vulpes in the 1930s, and the Dingo took a big toll on the quokka population. Also, the expanding human imposition on both the mainland and islands is hurting Setonix brachyurus , as their habitat is being destroyed. Since they are such a friendly species, unafraid of humans, people sometimes feed them foods that are harmful. Climate change could also be a factor in the decline of quokkas. Although their bodies are good at tolerating dry summers and conserving water, as temperature rises and rainfall decreases, arid summers can grow harsher. This will continue to hinder species’ habitat, shelter, diet and survival. Using the most severe climate change scenario, it is hypothesized that all species range will be lost by the year 2070. Conservation efforts are in place to help rehabilitate this species abundance. Populations on the mainland are being preserved in natural reserves and parks. Also, by researching their natural habitat, conservation managers are better able to promote the proper vegetation growth that sustain these populations.

Additional Links

Encyclopedia of Life

Contributors

Breanne Gartmann (author), University of Wisconsin - Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point.

References

Curtin University, 2016. "Wallaby's perception of color is more similar to a dog than a quokka" (On-line). ScienceDaily. Accessed April 29, 2016 at https://www.sciencedaily.com/releases/2014/01/140130102032.htm .

Gibson, L., A. McNeill, P. de Tores, A. Wayne, C. Yates. 2010. Will future climate change threaten a range restricted endemic species, the quokka ( Setonix brachyurus ), in south west Australia?. Biological Conservation , 143: 2453-2461.

Hart, R., S. Bradshaw, J. Iveson. 1985. Salmonella infections in a marsupial, the quokka ( Setonix brachyurus ), in relation to seasonal changes in condition and environmental stress. Applied and Environmental Microbiology , 49/5: 1276–1281.

Hayward, M., P. de Tores, P. Banks. 2005. Habitat use of the quokka, Setonix Brachyurus (Macropodidae: Marsupialia), in the Northern Jarrah Forest of Australia. Journal of Mammalogy , 86/4: 683-688.

Hayward, M., P. de Tores, M. Dillon, B. Fox. 2002. Local population structure of a naturally occurring metapopulation of the quokka ( Setonix brachyurus Macropodidae: Marsupialia). Biological Conservation , 110/3: 343-355.

McLean, I., E. Cameron, W. Linklater, N. Schmitt, K. Pulskamp. 2009. Partnerships in the social system of a small macropod marsupial, the quokka ( Setonix brachyurus ). Behaviour , 146: 89-112.

Quoy and Gaimard, 2012. "Department of Environment and Conservation: Fauna profiles" (On-line). Quokka. Accessed April 06, 2016 at https://www.dpaw.wa.gov.au/images/documents/plants-animals/animals/animal_profiles/quokka_2012.pdf .

Storr, G. 1964. Studies on Marsupial nutrition; diet of the quokka, Setonix brachyurus , on Rottnest Island, Western Australia. Australian Journal of Biological Sciences , 17: 469-481.

Wynne, C., B. Leguet. 2004. Detour behavior in the Quokka ( Setonix brachyurus ). Behavioural Processes , 67/2: 281–286.

2014. "AnAge entry for Setonix brachyurus " (On-line). AnAge: the animal ageing and longevity database. Accessed April 29, 2016 at http://genomics.senescence.info/species/entry.php?species=Setonix_brachyurus .

A-Z Animals. 2016. "Quokka" (On-line). a-z animals. Accessed March 20, 2016 at http://a-z-animals.com/animals/quokka/ .

Department of the Environment. 2016. " Setonix brachyurus — Quokka in Species Profile and Threats Database" (On-line). Australian Government: Department of the Environment. Accessed April 29, 2016 at https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=229 .