Tragelaphus fasciatus (Pocock, 1900)

Don E. Wilson & Russell A. Mittermeier, 2011, Bovidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 444-779 : 600-601

23.

Eastern Coastal Bushbuck

Tragelaphus fasciatus

French: Guib cotier / German: Ostkisten-Schirrantilope / Spanish: Bushbuck de costa

Taxonomy. Tragelaphus scriptus fasciatus Pocock, 1900 ,

Sen Morettu, Webi Valley, Gallaland.

The mtDNA of two specimens of the Eastern Coastal Bushbuck (one from Tana River and one from Mona Mofa in Somalia) clustered with a T. sylvaticus specimen (ascribed to roualeyni) from Thabazimbi, Limpopo, South Africa. Two other specimens from Mona Mofa clustered with a number of T. sylvaticus specimens from localities in Tanzania, Malawi, and Zimbabwe, which suggests a history of introgression between this species and T. sylvaticus . The Eastern Coastal Bushbuck was formerly considered a subspecies of T. scriptus , but it is diagnostically different from other bushbucks. Synonyms of the Eastern Coastal Bushbuck include olivaceus and reidae . Monotypic.

Distribution. SE Ethiopia, Somalia, E Kenya, and NE Tanzania.

Descriptive notes. Head—body 117-145 cm (males) and 114-132 cm (females), tail 19— 24 cm, shoulder height 64-100 cm (males) and 61-85 cm (females); weight 40-80 kg (males) and 24-60 kg (females). These measurements are general for the bushbuck group and should be considered provisional until further information is available for individual species. Tragelaphines are sexually dimorphic, and males generally weigh about 160% of the weight of females. Bushbucks are the smallest tragelaphines. They have large ears and eyes and a rather round crested back, and their hindquarters tend to be higher and more robust than their forequarters. Male Eastern Coastal Bushbucks are dark gray-brown on the back and gray on sides, females are yellowish, and young are rufous. Both sexes have 4-6 white stripes that are generally distinct, a broken longitudinal white flank-band, and many white haunch spots. There is no black on the crown and nose. Females have a chevron between the eyes. Inguinal glands occur ahead of the mammae, but there are no false hoof glands. Tails are relatively short, long-haired, and bushy, dorsally colored the same as the back, white underneath, and usually tipped in black. Only males have keeled horns, which are nearly straight with generally only one or slightly more twists. Average length of the horns of the Eastern Coastal Bushbuck is about 34-35 cm. Average total length of the skull is 25-3 cm. Dental formulais10/3,C0/1,P 3/3, M 3/3 (x2) = 32. Diploid numbers for the bushbuck group are 33 for males and 34 for females.

Habitat. As a group, bushbucks are the most ubiquitous hoofed mammals in Africa, but because of their relatively solitary nature (particularly males), relatively small size, tendency to freeze and cryptically blend into their surroundings, and preference for forest and forest edge, they are difficult to observe and census. According to Y. Moodley and M. W. Bruford, the Northern Zanzibar-Inhambane Coastal Forest Mosaic ecoregion is occupied, but not exclusively, by the Eastern Coastal Bushbuck haplogroup. They are usually found near free water, which may be as much a reflection of their preferred forested habitats thriving near water as a physiological need.

Food and Feeding. There is no specific information available for this species, but its feeding habits are probably comparable to other bushbuck species, which eat a variety of shrubs, legumes, and other herbaceous plants as well as new-growth of grasses. They are fond of the fruits of various trees and can be observed feeding on fallen fruits under trees where baboons and other monkeys are foraging. In various locations, bushbucks are agricultural pests eating various crops by night.

Breeding. Bushbucks have been described as the most socially primitive of the tragelaphines and are typically thought of as non-terrritorial polygynous breeders (but see the Nile Bushbuck for the most thorough studies of breeding behavior).

Activity patterns. There islittle specific information available for this species, but activity patterns are probably comparable to the general bushbuck pattern, being crepuscular and nocturnal and spending much of the day resting/ruminating in forest cover, often alone, or pairs of mother—offspring.

Movements, Home range and Social organization. There is little specific information available for this species, but it is probably comparable to other bushbuck species (see the Nile Bushbuck for the most thorough studies of these characteristics). Bushbucks do not range over a wide area. Home ranges are not exclusive, but individuals do have their own, apparently exclusive, place to rest during the day. Although not aggressive to one another, regular social interactions among bushbucks are largely confined to mother—offspring pairs and male—females during rut.

Status and Conservation. Classified as Least Concern on The IUCN Red List (under 1. scriptus ), which does not differentiate the eight species identified here. In the late 1990s, numbers of bushbucks range-wide were estimated conservatively at over 1-34 million and they were not particularly dependent on conservation initiatives, such as protected areas, if adequate cover and water were available. Bushbuck populations are considered stable range-wide, although in localized areas, some populations have decreased because of excessive illegal harvest, destruction of native habitats as human populations and livestock numbers have increased, and increased aridity. Generally, however, bushbucks can do well in areas of human habitation because of their secretive nature, non-herding tendencies, cryptic coat patterning and tendency to freeze and blend in with their surroundings when faced with danger. They are flexible as to daily schedules, adopting a nocturnal pattern in areas of human activity. Subsistence hunting in Arabuko-Sokoke Forest in south-eastern Kenya reduced the Eastern Coastal Bushbuck to very low levels by the mid-1990s. Habitat loss to agriculture and likely civil unrest has reduced numbers of the Eastern Cape Bushbuck in Somalia.

Bibliography. Ansell (1972), Bro-Jorgensen (2008), East (1999), Estes (1991a, 1991b), Fitzgibbon et al. (1995), Groves & Grubb (2011), IUCN/SSC Antelope Specialist Group (2009), Kingdon (1982, 1997), Loth & Prins (1986), Lydekker & Blaine (1914), Moodley & Bruford (2007), Moodley et al. (2009), Nowak (1999), Olson et al. (2001), Walther (1990a), Wronski & Moodley (2009).

Figures

14. Saola (Pseudoryx nghetinhensis), 16. Chowsingha (Tetracerus quadricornis), 17. Nyala (Nyala angasii)

Distribution. SE Ethiopia , Somalia , E Kenya , and NE Tanzania .