Fat-Tailed Dunnart

## Description

The fat-tailed dunnart (Sminthopsis crassicaudata ) is a species of mouse-like marsupial of the Dasyuridae, the family that includes the little red kaluta, quolls, and the Tasmanian devil. It has an average body length of 60–90 millimeters (2.4–3.5 in) with a tail of 45–70 millimeters (1.8–2.8 in). Ear length is 14–16 millimeters (0.55–0.63 in). One of the smallest carnivorous marsupials, its weight varies between 10–20 grams (0.35–0.71 oz). The tail becomes fat a few mm from the proximal end and remains so right up to the tip. They have trichromat vision, similar to some other marsupials as well as primates but unlike most mammals which have dichromat vision. They are eaten by many things, including invasive foxes and cats, as well as other feral animals that live among its environment.

## Distribution

Fat-tailed dunnart is an Australian marsupial, found west of the Great Dividing Range and south of the Tropic of Capricorn. This animal inhabits a wide variety of environments from the southern coast to the arid inland regions, occurring in open woodlands, shrublands and grass-lands.

## Behavior

Fat-tailed dunnarts are nocturnal and solitary animals, but sometimes they forms small groups. They spend their daytime hours sleeping in dark, secluded places. During the cooler seasons, they nest and sleep in groups to conserve heat. They can also nest with other animals, including the common house mouse. Each individual has its own home range. They have large territories, which overlap and can change during the year. Females of this species are known for their highly territorial behavior, fiercely defending the territory, surrounding their nesting site as they have older young. However, males do not appear to be territorial. In order to save energy, fat-tailed dunnarts can undergo winter torpor, which is similar to hibernation and can last from just a few hours to several days. When dunnarts awake from the torpid state, they use a lot of energy in order to raise their body temperature. During these periods, they typically spend their time sunbathing.

## Diet

This marsupial are mainly insectivores. Their diet consists of various insects such as beetles or spider larvae, with addition of amphibians and small reptiles.

## Reproduction

Fat-tailed dunnarts may exhibit either polygynous or polygynandrous (promiscuous) mating systems, having multiple partners over their short lifetime. Reproduction depends on weather conditions: if there are suitable conditions, females can breed and give births without breaks for up to 6 months. Fat-tailed dunnarts breed from July to February. Gestation period lasts for 13 - 16 days, yielding a litter of 6 - 8 young, sometimes up to 10. Females of this species are usually solitary nesters. They build their nesting sites from dried vegetation under logs, rocks or in deep ground hollows. Newborn babies remain in the pouch of their mother, before they leave it permanently at 60 days old. After that, the female can leave her young in the nest while she forages. Complete weaning occurs at about 70 days old. Sexual maturity is reached at 4 - 5 months old. Females first breed during the first year of their lives.

## Population

### Population threats

Fat-tailed dunnarts generally suffer from the same threats as most small mammals in Australia. They are threatened by loss of their natural habitat. Fat-tailed dunnarts compete with pest animals of their range. They are predated by cats, foxes and other feral species. And finally, these marsupials may be mistaken for mice and as a result, trapped.

### Population number

According to IUCN, the Fat-tailed dunnart is common and widespread throughout its range but no overall population estimate is available. However, today this species’ numbers are stable, and it’s currently classified as Least Concern (LC) on the IUCN Red List.

## Fun Facts for Kids

Newborn babies of this species are extremely small, even smaller than a grain of rice.

Fat-tailed dunnarts both in captivity and in the wild enjoy eating hard-boiled eggs and minced meat.

These marsupials may both feed upon the common house mice when hungry and huddle together with them in the same nest to warm up during the cold season of year.

Fat-tailed dunnart is a night forager and night feeder. This animal is able to eat as much food as its own weight.

Instead of drinking water, these dunnarts get all required moisture from their food.

In order to save energy, Fat-tailed dunnarts may occasionally undergo torpid state during the day, which is a short period of dormancy. They usually enter torpor during mating and development. In addition, lactating females are known to undergo periods of torpor, which have no negative effects on their young.

When in torpor, their body temperature decreases from 34.8 to 14.6 degrees of Celsius.