Fawn hopping mouse  (Notomys cervinus)

The fawn hopping mouse is classified as Vulnerable (VU) on the IUCN Red List (1).

An inhabitant of the arid Australian outback, the fawn hopping mouse (Notomys cervinus), also known as the ‘ooarri’ (3), has elongated hind legs and feet on which it hops gracefully and rapidly (4). This species has a small head with long ears and great, bulging, black eyes, and its snout bears whiskers which can reach up to a remarkable 6.5 centimetres long (2). The fur on the back ranges from fawn with a pinkish hue to grey in colour, whereas the fur on the abdomen is white (2). The tail is longer than the body and ends in a tuft of dark hairs (2).

The adult male fawn hopping mouse possesses a glandular area of raised and hairless skin on the chest (2). This patch of skin, which is assumed to be used in scent-marking (5), is also evident in the female during periods of pregnancy and lactation (3).

The fawn hopping mouse may sometimes be confused with the closely related dusky hopping mouse (Notomys fuscus) and spinifex hopping mouse (Notomys alexis). However, the fawn hopping mouse can be distinguished by its lack of a throat pouch (2).

The fawn hopping mouse is endemic to Australia, where it is sparsely distributed in the Lake Eyre basin, in north-east South Australia and south-west Queensland. It has also been recorded from the Northern Territory, although it is unclear whether it still occurs there as it was not found during intensive surveys in 2004 (2).

The fawn hopping mouse inhabits gibber plains with low chenopods and short-lived plants. It may also venture onto adjacent claypans (2) (3).

The nocturnal fawn hopping mouse tends to live in family groups, usually comprising two to four individuals (2). During the day, it dwells in burrows which measure up to one metre deep and have between one and three entrances (2). At night, the fawn hopping mouse ventures out to forage. Seeds are the primary component of the fawn hopping mouse’s diet, but it will also eat small pieces of vegetation, as well as insects (2). When travelling rapidly, the fawn hopping mouse hops on its hind feet, but when travelling slowly it moves rather awkwardly on all fours (4).

Like other members of the Notomys genus, the fawn hopping mouse does not need to drink water, an incredibly useful adaptation in its harsh, arid habitat. Instead, this species has the ability to turn some of the carbohydrate obtained from seeds into water, and is able to reduce the amount of water lost in its urine and faeces (6).

The fawn hopping mouse will only breed when the conditions are suitable (2), often resulting in great fluctuations in the population size (1). Females give birth to between one and five individuals after gestation period of 38 days (1) (4). The young, which are born in a nest chamber lined with leaves and other plant material (4), weigh just 2 to 4 grams at birth, and do not open their eyes until 18 to 28 days old. The young cling to their mother’s nipples and are carried about in this manner until they are weaned at around one month old (7).

Although no major widespread threats to the fawn hopping mouse have been identified, its numbers are believed to be decreasing (1). Possible reasons for this decline include habitat degradation, predation by introduced cats and foxes and competition with introduced herbivorous cattle and rabbits (2).

Habitat degradation can be caused by feral ungulates trampling the ground in which the fawn hopping mouse burrows, leaving the burrows unstable and vulnerable to wind and water erosion (1).

The effect of climate change has the potential to greatly threaten this species in the future. Global warming and the resultant reduction in rainfall may reduce productivity in the vegetation, which provides food and suitable burrowing habitat (1).

There are currently no specific measures in place to conserve the fawn hopping mouse. However, some of its habitat falls within the Ethabuka Reserve and the Diamantina Lakes National Park (1). Whilst these reserves protect populations of fawn hopping mouse in the north of the range, those in the south of the range still require protection (1).

Fawn hopping mouse populations need to be monitored, and studies need to be undertaken into the effects of predators, competitors and lower levels of rainfall (1).

Learn about conservation in Australia:

• Australian Conservation Foundation:
  http://www.acfonline.org.au/
• The Wild Australia Program:
  http://wildaustralia.org/