Perception Channels: tactile ; chemical
Spinifex hopping mice are abundant and widespread, they are not threatened.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Population explosions have been recorded for N. alexis. In 1975, a plague of N. alexis occurred. At this time, several hundred were reported being seen by spotlight by observers. It was also reported that they would enter campsites and steal scraps of food (Watts and Aslin, 1981).
These small mice are sometimes kept as pets (Verberne, 2002). They are also used extensively in laboratories in Australia (Murray and Dickman, 1994).
Positive Impacts: pet trade ; research and education
Notomys alexis serve as seed dispersers for many different plants. They occupy a unique niche and coexist with 10 to 12 other small mammal species. Most of these species are other rodents, but some are dasyurid marsupials (Murray and Dickman, 1994).
Ecosystem Impact: disperses seeds
Notomys alexis individuals eat mainly seeds, but also consume green plants and insects when available. They are not completely granivorous. A study has shown that they eat about 50% seeds and 50% invertebrates and supplement their diet with green plants (Murray and Dickman, 1994). These hopping mice can survive without free water by utilizing water in their food and efficiently using metabolic water.
Animal Foods: insects
Plant Foods: leaves; seeds, grains, and nuts
Primary Diet: omnivore
Notomys alexis is found in the sandy soils of Central Australia to Western Australia. Found abundantly in the Great Victoria Desert of Western Australia, N. alexis is the most abundant of all hopping mice in Australia (Watts and Aslin, 1981).
Biogeographic Regions: australian (Native )
Notomys alexis lives in sandy soils in areas of plains and dunes. They have been found in eucalypt woods, acacia shrubland, and tussock grassland. Notomys alexis characteristically live in areas with hummocks of spiky spinifex. This vegetation gives N. alexis the common name of Spinifex Hopping Mouse. These hopping mice live in deep, simple burrows in the sand (Watts and Aslin, 1981).
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune ; scrub forest
Spinifex hopping mice live as long as 3 years in captivity but probably much less in the wild. Most may live less than a year.
Average lifespan
Status: captivity: 3 years.
Average lifespan
Status: captivity: 5.2 years.
Notomys alexis are light brown to chestnut dorsally and gray to white ventrally. They are relatively large for a mouse species. The tail is relatively long and colored brown on the top and lighter on the bottom. The tip of the tail has a brush on it but the brush is smaller than in related species. A throat pouch is present in both sexes and may vary in appearance as the sexual state of the animal changes (Watts and Aslin, 1981). Adults weigh 20 to 50 grams. Body and head length ranges from 91 to 177 mm, average tail length is from 125 to 225 mm (Verberne, 2002).
Range mass: 20 to 50 g.
Range length: 91 to 177 mm.
Other Physical Features: endothermic ; bilateral symmetry
Average basal metabolic rate: 0.252 W.
Being active after dark and hopping quickly, in varying directions, helps N. alexis to avoid predators (Watts and Aslin, 1981). Most small to medium-sized predators in the regions where they live probably prey on spinifex hopping mice.
Known Predators:
Although females can mate with multiple partners, no obvious intermale competition occurs. In captivity, females have been observed mating with more than one male during a single estrous cycle. When the paternity of the litter was tested, all the young were found to be from the same male (Hyde and Elgar, 1992).
Mating System: polygynandrous (promiscuous)
Notomys alexis are opportunistic breeders. Although they can breed when conditions are not perfect, reproduction increases after periods of rain. Females can start breeding at 85 days old and have an estrous cycle of seven to eight days. Gestation ranges from 32 to 34 days if the female is not lactating. If a female is lactating, the gestation period can increase to about 40 days. Estrus continues during lactation and finding a female that is pregnant and lactating is not uncommon. Breeding can be inhibited by a high population density of N. alexis (Watts and Aslin, 1981).
Breeding season: Breeding occurs throughout the year but particularly after rains.
Range gestation period: 32 to 40 days.
Average weaning age: 28 days.
Range age at sexual or reproductive maturity (female): 85 (low) days.
Range age at sexual or reproductive maturity (male): 85 (low) days.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 2.83 g.
Average number of offspring: 3.9.
Pink and sparsely furred, the young weigh about 3 grams when they are born. It takes about 15 days for the ears to open and 20 days for the eyes to open. They are cared for and nursed in the nest by their mother until they are weaned, at about 28 days (Watts and Aslin, 1981).
Parental Investment: altricial ; female parental care
The spinifex hopping mouse (Notomys alexis), also known as the tarkawara or tarrkawarra, occurs throughout the central and western Australian arid zones, occupying both spinifex-covered sand flats and stabilised sand dunes, and loamy mulga and melaleuca flats.
The population fluctuates greatly: in normal years it is sparsely distributed and probably confined to sandy country; after rain the population explodes and spreads to other types of habitat for a time.
They are mostly seen at night, bounding across open ground on their large hind feet, with tails extended and the body almost horizontal.
As semi-fossorial, burrowing surface foragers, the tiny hopping mice spend a great deal of energy not just foraging for food, but also transporting it back to their burrows. In fact, it was found that the total energy spent on transporting food in relation to energy investment on burrows far outweighed any other similar type of species (White, 2006).
The appearance is very similar to the northern hopping mouse: slightly larger than a common house mouse at 95 to 115 mm (3.7 to 4.5 in) head-body length and an average weight of 35 g (1.2 oz). As with all hopping mice, the hind legs are greatly elongated, the fore limbs small, and the brush-tipped tail very long—about 140 mm (5.5 in). The fur is chestnut or fawn above, pale below, with a grey wash about the muzzle and between the eye and ear, and longer, coarse black guard hairs on the back. The tail is sparsely furred and pink, darker above than below.
Spinifex hopping mice live in small family groups of up to 10 individuals in deep, humid burrow systems. Typically, there is a large nest chamber lined with small sticks and other plant material about a metre below the surface, from which several vertical shafts lead upwards. Shaft entrances do not have spoil heaps.
Breeding can be at any time of year depending on conditions, with spring being favoured. Pregnancy usually takes 38–41 days but can be prolonged significantly if the mother is still suckling the previous brood. Litters of three or four are typical, six being the maximum. The young remain in the nest while the female forages; if they wander both male and female adults retrieve them. They reach sexual maturity in about two and a half months. After mating, a copulatory plug is formed in the female's reproductive tract.[2]
The spinifex hopping mouse is widespread and although the population fluctuates considerably, is not considered at risk.
Previously, spinifex hopping mice could be kept as pets in Victoria (Australia), but a Basic Wildlife Licence was required. In 2013, Victorian regulations for the possession, use and trade of wildlife underwent a number of changes and as part of these reforms spinifex hopping mice were moved to Schedule 4B, which allows private ownership without a licence.[3] Commercial breeding still requires a licence to prevent removal of mice from the wild. Pet owners should be aware of the potential parasite and disease risks, including mites[4] and helminths,[5] and in very rare cases even melanoma.[6]
Captive populations of spinifex hopping mice are useful for small scale research, and can be used for developing management tools to assess the health status of those in captivity.[7]
The spinifex hopping mouse (Notomys alexis), also known as the tarkawara or tarrkawarra, occurs throughout the central and western Australian arid zones, occupying both spinifex-covered sand flats and stabilised sand dunes, and loamy mulga and melaleuca flats.
The population fluctuates greatly: in normal years it is sparsely distributed and probably confined to sandy country; after rain the population explodes and spreads to other types of habitat for a time.
They are mostly seen at night, bounding across open ground on their large hind feet, with tails extended and the body almost horizontal.
As semi-fossorial, burrowing surface foragers, the tiny hopping mice spend a great deal of energy not just foraging for food, but also transporting it back to their burrows. In fact, it was found that the total energy spent on transporting food in relation to energy investment on burrows far outweighed any other similar type of species (White, 2006).
