The Malagasy giant jumping rat is restricted to two main fragments of dry deciduous forest, totalling 300km2 in extent, in central western Madagascar. After many years of range decline through habitat loss, the population has thought to have stabilised in the last 5 years and now numbers over 30,000 individuals. However, the species appears to be highly vulnerable to habitat degradation and disappears from heavily exploited forest areas. Classified as Endangered (EN B1ab(iii,v)) on the IUCN Red List of Threatened Species.
The main threat to this species is habitat loss and degradation through agricultural encroachment and fuelwood collection. This threat has varied in intensity and extent over the last 10 years.
The Menabe Antimena protected area has been temporarily designated by the Malagasy Government, which is due to be made permanent in 2014 or 2015, and encompasses the majority of the Malagasy giant jumping rat’s dry forest habitat. The Menabe Antimena protected area is co-managed by local communities and the statutory authorities. Durrell Wildlife Conservation Trust leads an intensive monitoring programme to track population trends.
For a threatened small mammal, this species is well studied. It occupies a niche which is filled elsewhere in the world by rabbits. It builds long, deep burrows in which it sleeps during the day. Typical burrow complexes are 5 m in diameter and have 1-6 holes. The entrances to these holes are usually kept plugged with a barrier of soil and leaves, which the animals have to excavate and re-seal each time they pass in and out. At night the species emerges to forage for food. It is believed to feed mainly on fallen fruit, seeds and leaves. Unusually for rodents, this species is monogamous – a mated pair and their most recent offspring live together in a single burrow. Pairbonds apparently last until one mate dies. The pairs defend an exclusive territory of around 3.5 ha, marking their boarders with urine, faeces and scent gland deposits. The minimum population density in favourable habitat is 48/ha. Males reach sexual maturity at one year, at which time they leave the parental burrow and set up their own territories. Females mature at two years, but usually remain with their parents for at least one breeding season subsequent to this. Reproduction occurs in the rainy season (December – March) and females usually give birth to one or occasionally two young. Females are thought to be capable of giving birth twice during the reproductive season when food is plentiful, although this rarely happens. Infant mortality is high, with only around 50% of young surviving to adulthood. The species is an important prey species for the fossa (Cyprtoprocta ferox) and a ground boa constrictor (Acrantophis dumerili). They also play an important role in seed dispersal, and aerate the soil though their fossorial behaviour. There is little information available on the lifespan of this species in the wild. In captivity giant jumping rats have a life expectancy of around 5 years.