395.

East African Vlei Rat

Otomys tropicalis

French: Otomys tropical / German: Ostafrika-Lamellenzahnratte / Spanish: Rata de laguna de Africa oriental

Other common names: Tropical Vlei Rat

Taxonomy. Otomys irroratus tropicalis Thomas, 1902,

west slope of Mt Kenya, 10,000 ft (= 3000 m), Kenya.

Otomys tropicalis previously was included in O. wrroratus and is clearly a composite of several unrelated species that await taxonomic revision. Monotypic.

Distribution. C & E Africa in Albertine Rift (DR Congo, Uganda, Rwanda,and Burundi), Imatong Mts (South Sudan), Mt Elgon (Uganda-Kenya), and Kenyan Rift (N & W Kenya); perhaps NE Tanzania (Msinga and lower slopes of Mt Kilimanjaro) where specimens may belong to this species.

Descriptive notes. Head-body 125-205 mm, tail 52-102 mm, ear 17-25 mm, hindfoot 26-34 mm; weight 81-133 g. The East African Vlei Rat is large and robust, with large blunt head, short tail, and shaggy fur. Fur is dark brown (raw umber) above, clear brown on flanks, and slaty gray below. Ears are medium-sized, well furred, and paler than body. Tail is short (c.46% of head-body length) and bicolored. Females have four pairs of nipples. Upper incisors have single groove, and lower incisors have deep lateral and shallow medial groove. M, has four laminae, and M* has seven or occasionally eight laminae.

Habitat. Montane and submontane habitats of dense moist grasslands, scrublands, degraded forest and forest clearings, and cultivated areas such as banana and coffee plantations at elevations of 840-2250 m. The East African Vlei Rat is mostly associated with the Albertine Rift, Mount Elgon, Kenyan Rift, and Imatong Mountains of South Sudan, but it has also been recorded at lower elevations (e.g. Kampala, Uganda and Garamba National Park in extreme north-east DR Congo).

Food and Feeding. East African Vlei Rats eat green grains, herbs, reed stems and shoots, bark, and occasionally roots, seeds, and berries. They cause extensive damage to forest plantations in DR Congo by ring-barking young saplings. Fragments of ants have been found in stomachs.

Breeding. Reproduction occurs year-round, with up to five litters per year. Litters have 1-2 young.

Activity patterns. The East African Vlei Rat is presumably diurnal or crepuscular.

Movements, Home range and Social organization. East African Vlei Rats can be abundant; densities were 16-40 ind/ha at one site in DR Congo.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Kingdon (1974), Monadjem et al. (2015), Taylor & Kumirai (2001), Taylor et al. (2011).