Dusky Hopping Mouse
Dusky hopping-mice are distributed from Ooldea in S Australia to past Lake Eyre to SW Queensland. They also currently inhabit the regions of SE Western Australia, S Northern Territory, Southern Australia, N New South Wales, and NE South Australia (southern Strzeleki Desert and the Cobblers Desert). Dusky hopping-mice inhabit sand dunes, grasslands, tree and shrub heaths, and lightly wooded areas. The temperature of their habitat is usually very high with desert-like conditions. N. fuscus also live in sand ridge habitats, which alternate with gibber flats and clay pans, in the Pelican Waterhole area.
Dusky hopping mouse
N. fuscus is characterized by its strong incisor teeth, long tail, large ears, dark eyes, and extremely lengthened and narrow hind feet, which have only four sole pads. Head and body length is 91-177 mm, tail length is 125-225 mm, and weight is about 20-50 grams. Coloration of the upper parts varies from pale sandy brown to yellowish brown to ashy brown or grayish.
The underparts of dusky hopping-mice are white. The body covering is fine, close and soft; and long hairs near the tip of the tail give the effect of a brush. Notomys fuscus has a well-developed sebaceous glandular area on the underside of its neck or chest. Females have four mammae.
Reproduction
Little is known of the breeding biology of this species in the wild other than that it is an opportunistic breeder. In captivity, its breeding pattern is polyestrous, with no evidence of seasonality, thus it breeds throughout the year. The gestation period is 38-41 days; a postpartum estrus is not common in N. fuscus, but some females enter estrus 14-22 days after giving birth.
The estrous cycle lasts about 7-8 days. Dusky hopping-mice rear litters of 1-5 young. Their young weigh about 2-4 grams at birth and open their eyes at 18-28 days. The young cling to the nipples of the mother and are dragged about wherever she goes, and weaning occurs at about 30 days. Both sexes of N. fuscus reach reproductive maturity at 70 days. It was seen that one female N. fuscus produced 9 litters in her lifetime of 26 months. Males are capable of breeding up to the age of 38 months.
Behavior
The sebaceous glandular area is active in all adult males but is active in females only during pregnancy and lactation. Nowak (1991) suggests that the glands are used for territorial marking and marking of group members, including newborn young. Dusky hopping-mice are saltatorial and normally move awkwardly on all fours or make short hops. If startled, they bound rapidly using only their large hind feet. The mice dig their own burrows, some being of a simple construction but others being complex. The dusky hopping-mouse digs a burrow on the flat top of a dune with a single tunnel about 10 cm in diameter, more than a meter below the surface and up to 5 m long.
It is connected to the surface by up to 6 vertical entrance shafts that are dug from below and may end up anywhere on the surface. A nest, consisting of a pad of finely chewed vegetation, is placed in the center of a small alcove off the main shaft, and well-marked pads connect different burrows along the top of the dune. The width of the entrance shafts is critical because the animals move in them by hopping; they brace their backs against the sides with their forefeet between hops. Progress when coming down a shaft is a headlong dive, with the back braced against the wall of the shaft and the forelegs used as a brake. If the entering animal finds that the burrow is blocked with loose sand, it often squeaks several times.
This usually attracts other occupants and together, from opposite sides, they rapidly clear the blockage. N. fuscus is commonly found in association with marsupial counterparts and sometimes shares the same tunnel systems. Living in groups of about five individuals in one or two adjacent burrows systems, the Dusky Hopping-mouse spends all its life on the dunes. Being a nocturnal animal, it rests in its burrow during the day, insulated from the hot surface. At night, it forages on the top and sides of a dune, and rarely ventures more than a few meters away. Even in apparently favorable localities, population density is low, with individuals inconspicuously congregated in a loose colony in a small area of a sandhill. Dusky Hopping-mice calls include twittering during animated chases. However, none of the sounds was associated with threats or fighting.
Food Habits
Notomys fuscus is like other hopping-mice in that it does not drink, but obtains all its water and food requirements from a diet of seeds, berries, leaves, green plants and occasionally insects. In captivity they should be offered a complete diet of rodent lab blocks, and rat or mouse mix, with bits of fruit or veggies regularly. Cheerios or wheat bread are great treats, in small quantities. Do NOT feed chocolate, fried foods, salted foods, candy or junk food! They may enjoy crickets and mealworms if they are captive bred, never feed wild insects as they may carry parasites. Vitamins, like Nutri-Cal are a good addition to their diet, and added calcium during nursing and growth due to demands on their systems at those times, but take care not to overdo it. Water bottles should be used to proved constant, clean water. Ceramic or stoneware food dishes work well for keeping seeds or fresh foods off the floor, and a wire mesh hopper that allows them to eat the lab blocks through without extra waste.
