Elephantulus rufescens (Peters, 1878)

Russell A. Mittermeier & Don E. Wilson, 2018, Macroscelididae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 206-234 : 231

11.

Rufous Sengi

Elephantulus rufescens

French: Sengi roux / German: Rotbraune Elefantenspitzmaus / Spanish: Sengi bermejo

Other common names: East African Long-eared Elephant-shrew, East African Long-eared Sengi, Rufous Elephantshrew, Rufous Spectacled Elephant-shrew, Rufous Spectacled Sengi, Spectacled Elephant-shrew, Spectacled Sengi

Taxonomy. Macroscelides rufescens Peters, 1878 ,

Ndi , Taita, Kenya.

Six subspecies are recognized.

Subspecies and Distribution.

E.r.rufescensPeters,1878—E&SKenya;SSomaliaspecimensmaybethissubspecies.

E.r.boranusThomas,1901—SEthiopia.

E.r.dundasiDollman,1910—SESouthSudan,Uganda,andKenya.

E.r.peaseiThomas,1901—EEthiopia.

E.r.pulcherThomas,1894—Tanzania.

E. r. somalicus Thomas, 1901 — N Somalia.

Descriptive notes. Head-body 102-199 mm, tail 111-163 mm, ear 22-39 mm, hindfoot 30-54 mm; weight 47-70 g. In some regions of the distribution, female Rufous Sengis can be slightly larger than males, but there generally is not substantial sexual dimorphism in body size. Tail is relatively long at c.105% of head-body length and dark brown with sparse hair; it lacks terminal tuft. Pinnae are broad, upright, and nearly hairless. Snout is long, thin, and flexible. Color of dorsum varies by region and includes rufous, gray, buff, and yellow tones; these variations might be associated with colors of habitat substrates. Tips of dorsal hairs are dark gray or gray-buff. Behind each ear, patch of buff hair extends onto nape of neck. Venter is pure white, and pectoral gland is fringed with distinguishable short white hairs. In adults, manus and pes are white (brown in juveniles). Rhinarium is hairy below. Prominent white eye-ring is present, with post-ocular patch of brown-black hair that intrudes on eye-ring and extends posteriorly. White ‘brow’ branching from eye-ring sweeps superiorly adjacent to post-ocular patch and extends to near base of ear. Hairy inferior rhinarium and spectacled pelage pattern around eyes are traits shared only with the Somali Sengi (E. revoilii). Females have two anterior, two intermediate, and two posterior nipples; males have no nipples. Five digits are present on each manus and pes. Pectoral gland is present, and subcaudal gland is present but only slightly developed. Dental formulais13/3,C1/1,P 4/4, M 2/2 (x2) = 40. Size of second upper incisor is distinctly smaller than both adjacent upper incisors. Canine sizes are subequal to adjacent teeth. Several bilateral pairs of palatal foramina are present. Postorbital processes are absent. Karyotype is 2n = 34.

Habitat. Arid woodlands and bushlands with open canopies and compact sandysoils, dominated by scrub vegetation and very little grass. In some areas of the distribution (e.g. Kibwezi, Kenya), rainfall patterns yield two wet seasons per year. The Rufous Sengi shelters at bases of bushes and among rocks.

Food and Feeding. Arthropods, mostly insects, are the principal diet of the Rufous Sengi. During wet seasons, small proportions of fruits and green plant matter are eaten. In south-eastern Kenya, an analysis of stomach contents found (in decreasing frequency) harvester termites, black ants, beetles, crickets, grasshoppers, spiders, and silverfish. Feeding is selective; in some areas, termites and ants are only c.40% of available invertebrate prey but c.75% of the diet.

Breeding. The Rufous Sengi is monogamous, and pairs mate for life. Reproduction occurs year-round, but births are more frequent during wet seasons. Smaller females (under 40 g) might carry only one embryo; larger females can carry up to two. Litters have 1-2 young. Gestation is ¢.57 days, and interbirth intervals are 57-65 days. Females can enter estrus almost immediately postpartum. Birth weight is c.10 g, and for the first 50 days daily gain is c.0-75 g. Young are highly precocial at birth, with open eyes and ability to run within a few hours. Mothers visit young perhaps only once per day to nurse young. There is no direct paternal care of young. Juveniles are weaned at ¢.30 days, after which parents aggressively chase them away from their territory. No species of soft-furred sengis use nests to shelter or for rearing their young.

Activity patterns. Rufous Sengis are fully terrestrial. Activity is polycyclic, with crepuscular peaks and some nocturnal tendencies. Midday activity is least frequent.

Movements, Home range and Social organization. Home ranges of monogamous pairs overlap, but combined area has limited overlap with home ranges of neighboring pairs. If a male disappears, a neighboring male might engage in temporary polygyny during the vacancy. Home ranges are reported to be 0-2-0-5 ha. Individuals of a pair interact infrequently except during estrus. Both sexes aggressively defend their territory; males chase away males, and females chase away females. Monogamous mating

system is probably a mate-guarding strategy. Trail systems are actively maintained by pushing aside debris with forelimbs and head.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Rufous Sengi is widespread and has a stable population trend.

Bibliography. Corbet & Hanks (1968), Evans (1942), Koontz & Roeper (1983), Lumpkin et al. (1982), Neal (1982, 1984), Olbricht & Stanley (2009), Perrin & Rathbun (2013g), Rathbun (1979b, 2009, 2015d), Rathbun et al. (1981).

Figures

1. Golden-rumped Seng (Rhynchocyon chrysopygus), 2. Chequered Sengi (Rhynchocyon cirne), 3. White-tailed Sengi (Rhynchocyon stuhlmanni), 4. Black-and-rufous Sengi (Rhynchocyon petersi), 5. Gray-faced Sengi (Rhynchocyon udzungwensis), 6. Namib Round-eared Sengi (Macroscelides flavicaudatus), 7. Karoo Round-eared Sengi (Macroscelides proboscideus), 8. Etendeka Round-eared Sengi (Macroscelides micus), 9. Four-toed Sengi (Petrodromus tetradactylus), 10. North African Sengi (Petrosaltator rozeti), 11. Rufous Sengi (Elephantulus rufescens), 12. Somali Sengi (Elephantulus revoulii), 13. Dusky-footed Sengi (Elephantulus fuscipes), 14. Short-snouted Sengi (Elephantulus brachyrhynchus), 15. Dusky Sengi (Elephantulus fuscus), 16. Bushveld Sengi (Elephantulus intufi), 17. Western Rock Sengi (Elephantulus rupestris), 18. Eastern Rock Sengi (Elephantulus mywrus), 19. Cape Rock Sengi (Elephantulus edwardii), 20. Karoo Rock Sengi (Elephantulus pilicaudus)

Subspecies and Distribution. E.r.rufescensPeters,1878—E&SKenya;SSomaliaspecimensmaybethissubspecies. E.r.boranusThomas,1901—SEthiopia. E.r.dundasiDollman,1910—SESouthSudan,Uganda,andKenya. E.r.peaseiThomas,1901—EEthiopia. E.r.pulcherThomas,1894—Tanzania. E. r. somalicus Thomas, 1901 — N Somalia.