Bunolagus monticularis is endemic to South Africa. It has an extremely limited geographic range, found only in the central and southern regions of the Karoo Desert of South Africa's Cape Province (Chapman and Flux, 1990).

Biogeographic Regions: ethiopian (Native )

Bunolagus monticularis is easily identified by the black stripe running from the corner of its mouth over its cheek, a brown woolly tail, cream-colored fur on its belly and throat, and a broad, club-like hind foot. Its tail is pale brown with a tinge of black toward the tip. Its coat is soft and silky and its limbs are short and heavily furred (Nowak, 1997). Male riverine rabbits weigh approximately 1.5 kg while females weigh about 1.8 kg (Duthie, 1987).

Range mass: 1.5 to 1.8 kg.

Range length: 337 to 470 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger

• Terrestrial

Bungolagus monticularis lives in dense riverine scrub along the seasonal rivers in the central Karoo Desert in the Cape Province of South Africa (Mills, 1997).

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: desert or dune ; scrub forest

Other Habitat Features: riparian

Bunolagus monticularis is predominantly a browser. It eats riparian vegetation found along seasonal rivers in the Karoo Desert. This includes salt-loving plants such as Salsola and Lycium, as well as flowers and leaves from boegoe and ink bushes (Mills, 1997). Grasses are included in the diet when these are available in the wet season. Bunolagus is also known to eat its day-time droppings which are soft, taken directly from the anus, and swallowed. By doing this, it takes in vitamin B, produced by bacteria in the hind gut, and minerals such as calcium and phosphorus are recycled (Burton, 1987).

Plant Foods: leaves; wood, bark, or stems; flowers

Other Foods: dung

Primary Diet: herbivore (Folivore ); coprophage

Bungolagus monticularis has a limited ecosystem role. The riverine vegetation it feeds on is known to bind soil and regenerates as the rabbit feeds on it. This means that the Riverine rabbit's feeding habbits indirectly prevents the soil from being washed away in floods (Duthie, 1987).

Bunolagus is capable of jumping over one meter high bushes when being pursued by a predator. To escape predatation, it remains nocturnal, spending the day resting in a form, a shallow scrape made in the soil, under a Karoo bush (Smithers, 1986).

Known Predators:

• black eagles (Ictinaetus malayensis)
• other carnivores (Carnivora)

Anti-predator Adaptations: cryptic

Bunolagus monticularis has never been kept in captivity. There is no information on its lifespan in the wild or in captivity currently available (Chapman and Flux, 1990).

Bunolagus monticularis is one of the rarest mammals in the world and very little is known about its reproductive behavior other than it has a polygynous mating system. Males mate with more than one female.

Mating System: polygynous

Little is known about the life cycle of Bunolagus monticularis. Females nest in subterranean chambers and produce a single offspring per year, which is an unusually low breeding rate for rabbits (Avery, 1997). Young are born helpless and blind, and they rely on their mothers for the first part of their lives. The young weigh about 40-50 grams when born (Smithers, 1986).

Breeding season: Breeding occurs from August through May.

Range number of offspring: 1 (low) .

Average number of offspring: 1.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Average birth mass: 45 g.

Average number of offspring: 1.

The young are altricial, underdeveloped at birth, and are born blind and hairless. They spend the first part of their lives with their mothers until they are able to move independently. Bunolagus monticularis is the only African rabbit that prepares an underground shelter for its young. This nest is 10-15 cm in diameter, 25 cm long, and lined with grass and fur (Nowak, 1997).

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)

Bunolagus monticularis is an endangered species. The most devastating threat to the riverine rabbit is the loss of its habitat. This habitat is limited to the alluvial floodplains of seasonal rivers in the central Karoo. These flood plains, only 100 - 200 m wide, are formed when the rivers overflow during floods, and deposit silt on their banks(Duthie, 1987). This soil is very good for cultivation compared with other soils found in the dry Karoo. Over the past 50 years, more than two-thirds of its habitat has been ploughed over for this purpose. Other threats to its survival include overgrazing and hunting. Overgrazing of riverine habitat opens up cover that it needs for shelter and to escape predation.

The only way to secure the long term survival of Bunolagus monticularis is to protect its natural habitat. The Dept. of Environment and Cultural Affairs has started a project which encourages farmers to form conservancies for this rabbit. Some Karoo farmers have taken this step and declared their farms Natural Heritage Sites to protect the riverine habitat and rabbit (Duthie, 1987).

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: critically endangered

The riverine habitat of Bunolagus monticularis provides many benefits for farmers. The riverine vegetation that the rabbit feeds on, causing this vegetation to regenerate, binds the soil and prevents it from being washed away in floods. Also, this vegetation promotes filtration of rainwater to groundwater, which is a benefit for the farmer who uses windmills to draw up water for his livestock (Burton, 1987). Indirectly, the habitat of Bunolagus monticularis helps humans in farming and can only be sustained if this rabbit continues to feed on this vegetation.