Rattus hoffmanni

687.

Hoffmann’s Sulawesi Rat

Rattus hoffmanni

French: Rat de Hoffmann / German: Hoffmann-Ratte / Spanish: Rata de Célebes de Hoffmann

Other common names: Hoffmann's Rat, Sulawesian Rat

Taxonomy. Mus hoffmanni Matschie, 1901,

Minahassa region, north-eastern Sulawesi, Indonesia.

Rattus hoffmanni is in the R. rattus species group and is closely related to R.molli-comulus and probably R. koopmani. A recent genetic. study found. it to be. sister to a clade consisting of the R. rattus clade and R tiomanicusin the R. rattus species group. Monotypic.

Distribution. Sulawesi, except Mt Lampobatang on SW peninsula, and Malenge I, Togian Is, Indonesia.

Descriptive notes. Head-body 142-211 mm, tail 145-210 mm, ear 20-25 mm, hindfoot 35-42 mm; weight 90-250 g. Hoffmann’s Sulawesi Rat is mediumto large-sized, with soft, short, and dense pelage. Dorsum is brownish black, highlighted with buff to paler brownish yellow or tawny speckled with black, always having gray underfur and inconspicuous guard hairs. Each eye has blackish ring. Venter is silver-gray, tinged with pale buff to rich dark buff with gray or dark gray underfur, respectively, sometimes with white patch or buff streak on chest. Juveniles are darker and softer than adults. Feet are brown dorsally. Ears are large, rubbery, and dark grayish brown; vibrissae are long and black. Tail is ¢.100% of head-body length, covered with short hair, and dark brown, sometimes grayish brown. Skull has long and wide rostrum. Blood flukes (Schistosoma japonicum), various nematodes (e.g. Cyclodontostomum purvisi), sucking lice (Hoplopleura sembeli), mesostigmatid, listrophoroid, anoedid mites, trobiculid chiggers (Leptotrombidium deliense, Schoengastia sulawesiensis, Ascoschoengastia indica, Eutrombicula wichmanni, Gahrliepia sp., Schoutedenichia sp.), and histiostomatid mites (Histiostoma sp.) have been recorded from Hoffmann’s Sulawesi Rat. There are four pairs of mammae: one post-axillary pair, one abdominal pair, and two inguinal pairs. Chromosomal complement is 2n = 42, FN = 61 (males) and 62 (females).

Habitat. [Lowland and montane tropical cool and moist forests, around streams, disturbed areas such as secondary growth and scrub, and shade-grown coffee plantations. Hoffmann’s Sulawesi Rats depend on good coverin their habitat.

Food and Feeding. Hoffmann’s Sulawesi Rat is frugivorous and somewhat accidentally insectivorous. Stomach contents contained pulp and seeds of figs (Ficus, Moraceae), some stems and leaves, and various insect parts from fruitflies, sclerites, and beetles. Insects are probably eaten when eating fig pulp. Captive individuals from montane mossy forests ate fruits of Eugenia sp. (Myrtaceae); an understory palm (Areca vestiaria) and rattans (Calamus sp.), both Arecaceae; screwpines (Pandanus sp., Pandanaceae); an understory shrub (Vacciniumsp., Ericaceae), and an understory fig. A captive lowland forest individual ate fruits from understory palms (Pinanga sp. and Licuala celebica, Arecaceae); understory figs (Ficus latimarginata, F. aurita, and FE fistulosa) and a canopy-forming strangler fig (Ficus sp.), all Moraceae; an understory tree (Madhuca sp.), and the canopy tree Saprum luzonicum (Euphorbiaceae). Lowland and highland captive individuals rejected acorns (Lithocarpus sp., Fagaceae) and various earthworms, insects and snails.

Breeding. Hoffmann’s Sulawesi Rat seems to breed year-round. Litters based on embryos counts had 4-5 young.

Activity patterns. Hoffmann’s Sulawesi Rat seems to be nocturnal. It is terrestrial and somewhat arboreal, sheltering in dense foliage, hollow bases of trees, and root cavities.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Hoffmann’s Sulawesi Rat is commonin its wide distribution, seems to have a stable overall population, and occurs in many protected areas. It might be threatened by habitat loss from logging and agricultural expansion in the lowland parts ofits distribution. It is apparently hunted by humans in the northern part ofits distribution, which is unlikely to be a major threat.

Bibliography. Cassola (2016ad), Dewi & Purwaningsih (2013), Hasegawa & Syafruddin (1994a), He Yixun et al. (2001), Musser (1982a), Musser & Carleton (2005), Musser & Holden (1991), Robins et al. (2007).