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Red Rock Rat

Aethomys chrysophilus

French: Aethomys roux / German: Rote Buschlandratte / Spanish: Rata de roca roja

Other common names: Red Aethomys, Red Veld Aethomys, Red Veld Rat

Taxonomy. Mus chrysophilus de Winton, 1897,

Mazoe, Mashonaland, Zimbabwe.

Aethomys chrysophilus previously included A. ineptus; the two cryptic species are morphologically indistinguishable, but are separated by molecular, chromosomal, reproductive, biochemical, biogeographical, and fine morphological characters. A. chrysophilus may possibly represent a species complex. Although karyotypes from northern and southern Tanzania accord with the typical karyotype of A. chrysophilus reported from Zimbabwe, cytochromeb sequences of specimens from Tanzania and Namibia are distinct from both A. ineptus and A. chrysophilus from South Africa and may represent one or more undescribed species. Monotypic.

Distribution. E & S Africa from EC & SW Kenya to SW Angola, Namibia, Mozambique, and N South Africa.

Descriptive notes. Head—body 120-169 mm, tail 135-190 mm, ear 15-27 mm, hindfoot 28-35 mm; weight 63-112 g. Males are on average larger than females, with considerable overlap in measurements between sexes. A medium-sized to large rat, the Red Rock Rat has fur thatis coarse and reddish brown dorsally and white ventrally; dorsal and ventral coloration sharply delineated. Ears are medium-sized and brown. Tail is very long (115-120% of head—body length) and coarsely scaled with fine hairs. Limbs are relatively short, and foreand hindfeet dorsally white or off-white, with four digits on forefoot and five on hindfoot. Chromosomal complement has 2n = 50, FNa = 60.

Habitat. Variety of savanna-woodland habitats, as well as agricultural and periurban habitats.

Food and Feeding. Omnivorous, the Red Rock Rat feeds on insects (25%), seeds (40%), and vegetation (35%), with increased dependence on seeds in dry season.

Breeding. Reproduction occurs throughout year, but with most births in late dry season and early wet season. Captures in late dry season are dominated by subadults and mortality is high, with 50% survival to one month, 30% to two months and 23% to three months. In captivity, gestation period is 26-31 days, with average litter size of 3—4 (range 1-6). Neonates have average weight of 4-5 g. Eyes open at 10-14 days, weaning occurs at 26-33 days; nipple-clinging lasts for three weeks after birth.

Activity patterns. Red Rock Rat are nocturnal. They are mostly terrestrial, but may also climb.

Movements, Home range and Social organization. Red Rock Rats are apparently territorial, with pairs widely spaced and rarely more than two individuals per burrow. In captivity, dominance hierarchy emerges to reduce aggression between individuals.

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

Bibliography. Chimimba et al. (1999), Denys et al. (2011), Gliwicz (1987), Happold (2013a), Linzey & Chimimba (2008), Linzey & Kesner (1997a, 1997b),Linzey et al. (2003), Monadjem et al. (2015), Russo etal. (2006), Taylor et al. (2012), Visser & Robinson (1986, 1987).