Mammals

This species 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.

The species only occurs in coastal dry deciduous forest mixed with baobabs resting on sandy and lateritic soils. It avoids degraded areas and secondary forests with open canopy and dense undergrowth.

The species only occurs at low densities and appears to be rare throughout its limited range. Numbers are estimated at around 11,000.

Decreasing.

Classified as Endangered (EN B1ab(iii,v)) on the 2010 IUCN Red List of Threatened Species.

This species has declined rapidly as a result of habitat loss and fragmentation, and predation from introduced species such as dogs. Its habitat is decreasing at an alarming rate due to illegal and commercial logging, slash-and-burn agriculture, charcoal production and burning for the creation of cattle pasture. The species appears to be very sensitive to human activity and will move away from areas of disturbed habitat. These threats are exacerbated by the extremely low reproductive rate of the species. Unlike most rodents, female giant jumping rats only have one or two offspring per year. Therefore the species does not have the potential for rapid population growth characteristic of many other rodents. Populations are expected to continue to decline over the next 100 years even if further habitat decline and mortality by roaming dogs can be stopped.

The northern subpopulation is severely threatened. It is currently without any protection, and is not connected to the southern population. Most of the southern population lies in the 12,5000 ha Kirindy Forest, a government-owned forest concession where sustainable forestry techniques have enabled many of the native species to survive. Research into the behavioural ecology of this species has been carried out for a number of years at the research station of the German Primate Centre (DPZ, Götingen, Germany) in the Kirindy Forest. The Durrell Wildlife Conservation Trust is working with the local Malagasy to conduct detailed surveys into the status and threats facing the wild population. It is also involved in a community education programme which aims to raise awareness of conserving the species’ forest habitat, and is working to get a part of the species remaining habitat declared an official protected reserve. In 1990, DWCT established a captive breeding programme for the species to safeguard against possible extinction in the wild. This programme has proven successful and there are now more than 50 giant jumping rats in twelve different institutions throughout the world, including London Zoo.

Since the species does not appear to tolerate human disturbance it is crucial that remaining areas of pristine habitat are protected before it is too late. The impact of introduced predators, such as dogs, on the population needs to be investigated, and methods of control brought in where necessary.

Durbin, J. & Goodman, S. 2008. Hypogeomys antimena. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.www.iucnredlist.org. Downloaded on 14 November 2010.

Durrell Wildlife Conservation Trust

Nowak, R.M. 1999. Walker's Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.

Sommer, S. 2001. Reproductive ecology of the endangered monogamous Malagasy giant jumping rat, Hypogeomys antimena. Mammalian Biology 66: 111-115.

Sommer, S., Volahy, A. T. and Seal, U. S. 2002. A population and habitat viability assessment for the highly endangered giant jumping rat (Hypogeomys antimena), the largest extant endemic rodent of Madagascar. Animal Conservation 5: 263-273.

Distribution map based on data provided by the IUCN Global Mammal Assessment.