In Australia’s arid and semi-arid zones live highly elusive predators known as kultarrs. They are small but fierce and feisty, with big eyes, long hind legs, and a pointy nose. A carnivorous marsupial, they come out at night to hunt their favorite foods: insects and spiders.
It’s rare for people to see this animal in the wild owing to a combination of its remote habitat, habit of hiding underground in the daytime, small size, camouflaged coat, and fast speed. For anyone lucky to see one in the wild, they’re very easy to confuse with a mouse.
But this animal isn’t a rodent — it’s a marsupial known as a kultarr (Antechinomys laniger). And only recently have scientists — including us — started to get a better grasp of their unique behavior and crucial role in the ecosystem.
A cousin of the Tasmanian devil
The kultarr is a cousin of the Tasmanian devil (Sarcophilus harrisii), as well as dunnarts, antechinuses, and phascogales.
Antechinuses and phascogales are known for “suicidal reproduction” or semelparity — dying after reproducing. Even though naturalist John Gould first described kultarrs as a type of phascogale (Phascogale laniger) in 1856, they do not reproduce in this way.
This small marsupial was given its unique genus name by Australian scientist Gerard Krefft in 1867. In 1906, a subspecies was named by British zoologist Oldfield Thomas.
Australian paleontologist Mike Archer suggested it was a type of dunnart in 1981, but more recent studies have confirmed that kultarrs and dunnarts are cousins and likely originated from a common ancestor.
Nevertheless, some clarity is needed as there are differences between the two subspecies we recognize today (A. l. laniger and A. l. spenceri). These include their geographic range, the length of their tail and body, mammary glands, and some cranial features.
Perhaps there is more than one species of kultarr?
A fierce predator
Kultarrs are found across most states and territories except Victoria and Tasmania. They are about the size of a mouse, weighing up to 30 grams. Their fur is brown, fawn, or sandy colored, and their belly fur is white. They also have a long tail with a brush‐like tip, and large elongated hind legs.
Although the long legs of the kultarr make it look like it hops, it is a quadruped. So rather than hopping like a kangaroo, kultarrs walk or run using all four legs at speeds of up to 13.8 km/h [8.6 miles per hour]. In comparison, the average human walking speed is roughly 4 km/h [2.5 miles per hour].
Like the Tasmanian devil, the kultarr is a fierce predator, although its prey is smaller — mainly consisting of arthropods. Studies of kultarrs in captivity have shown they have a very simple digestive tract and digest food very quickly, in about an hour.
During the daytime, kultarrs hide in cracks in the soil or burrows made by other animals such as native hopping mice. These cracks and burrows keep the kultarrs safe from predators while they sleep and provide a stable temperature that helps save energy. At night, they come out in search of food and mates.
Kultarrs also use torpor, a reduction in metabolic rate and body temperature, to save energy. They can adjust their body temperature to as low as 11°C [52°F], and stay in torpor for around 2-16 hours, particularly at times when temperatures are low and food is scarce.
Rarely observed in the field
As kultarrs are so elusive and rarely observed by field researchers, much of what we know about their biology is based on studies of them in captivity.
For example, captive studies have provided information on their reproduction and their behavior, such as warming up on heat rocks after using torpor to save energy.
Two recent studies analyzed historical footage of a captive colony of kultarrs to learn more about their behaviors.
The studies found the most common behaviors displayed in captivity were exploration of their environment and foraging for food. They were also looking out for potential predators by staying alert.
These behaviors are important when breeding animals for conservation actions, such as translocation and reintroduction, which involve relocating animals from one area to another to avoid threats or reintroducing captive-bred animals into their former habitat.
The studies highlight the importance of having captive colonies of native marsupials to further understand behavior and other aspects of their biology that are difficult to study in the wild, particularly in elusive nocturnal species like the kultarr.
A kultarr colony
Very few captive colonies of marsupials exist in research institutions.
In 2007, we established a kultarr colony at Western Sydney University. We learned a huge amount about kultarr biology during the six years the colony was operational. It helped provide new knowledge to aid species conservation and inform translocation or reintroduction programs.
Threats to kultarrs include habitat degradation, natural flooding events, fire, and pesticides. Introduced and native predators, such as feral cats, foxes, owls, and snakes, also prey on kultarrs.
Whole populations of kultarrs may migrate to new locations seasonally. We think that’s the case because researchers will do extensive surveys, find many, and then survey again, and there are none. Unlike rodents that boom after rainfall in response to better conditions — more food and habitat (plant growth) — kultarrs appear to be more readily seen in drier conditions.
The International Union for Conservation of Nature listed the kultarr as “data deficient” in 2008. Eight years later, it upgraded the species to the status of “least concern.”
But there is still a great deal we don’t know about these elusive little animals, particularly the current population stability — and even if there is more than one species of kultarr out there.
Hayley Stannard, Senior Lecturer in Animal Anatomy and Physiology, Charles Sturt University, and Julie Old, Associate Professor in Biology, Zoology and Animal Science, Western Sydney University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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