Strepsiceros zambesiensis (Lorenz, 1894)

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 : 615-616

36.

Zambezi Kudu

Strepsiceros zambesiensis

French: Koudou du Zambeze / German: Sambesi-GroRkudu / Spanish: Gran kudu oriental

Other common names: Greater Kudu

Taxonomy. Strepsiceros strepsiceros zambesiensis Lorenz, 1894 ,

Lesuma forest on the Zimbabwe —- Botswana border.

Recent assessments of the mtDNA control region of greater kudus from Namibia to northern Kenya suggested differentiation of at least chora to the north and zambesiensis, an east-central and south-western clade. S. frommi is a synonym. Monotypic.

Distribution. Tanzania (not extreme NW), extreme S DR Congo, Malawi, Mozambique, Zambia (not extreme N), S Angola, Namibia, Botswana, Zimbabwe, Swaziland, and N South Africa. Demarcation of the distribution between the Zambezi Kudu and the Northern Kudu ( S. chora ) in S Kenya and N Tanzania requires additional research.

Descriptive notes. Head—body 213-248 cm (males) and 205-217 cm (females), tail 41— 75 cm, shoulder height 142-157 cm (males) and 121-132 cm (females). No specific weights are available, but male Zambezi Kudus are about 150% heavier than females. Greater kudus are the tallest of the African antelopes, after elands ( Taurotragus spp.), with the longest and most widely spiraled horns on males. Male Zambezi Kudus vary from a grayish to pale ocher to reddish gray-brown; some white hairs may be mixed in the base pelage color. Ear-tips are occasionally white, but overall, they are a darker shade of the body color. Males have a very clear chevron on the face, but it is often short. The long throat mane is straw-colored or mixed pale red-brown and black; the hair tips are often blackish. Males have a short red-brown nuchal mane that becomes a white dorsal stripe, sometimes with black hairs mixed in, and is slightly lengthened at the first lateral body stripe. Males have 8-11 contrasting body stripes, but this is variable. The pasterns are brown and usually not black posteriorly. The lower legs are cinnamon. The average straight-line horn lengths of male Zambezi Kudus are 95.1-106. 8 cm, and average tip-to-tip lengths are 74.8-80. 4 cm; exceptional horn lengths along the outside curve may reach 160 cm. Young males can be aged by the shape of their horns: they have a full spiral by two years of age and 2-5 spirals by 4-4-5 years of age. Very rarely, females have horns. Female and young male Zambezi Kudus are ocher to bright grayish brown, with longer and redder hair than males. Their nuchal manes are long on the withers and reddish, with black hairs mixed in; their throat mane is short and straw-colored. The facial chevron is poorly developed on females. Unlike males, their ears do not have white tips. Females have 5-10 vertical stripes on the sides of the body. The dorsal stripe is vague in parts and white except where sporadically interrupted with black after the fourth stripe. Pasterns on females are black or brown. Dental formulais10/3,C0/1,P 3/3, M 3/3 (x2) = 32.

Habitat. Zambezi Kudus prefer woodland thickets, often on rocky escarpments and hills. Thickets along watercourses in Brachystegia woodlands often are frequented during the day. In Kruger National Park, South Africa, kudus occur in flat savannas of Acacia nigrescens and more upland savannas of Combretum apiculatum. In nearby Nylsvley Nature Reserve, savannas of Aristida bipartita—Setaria sphacelata, dominated by Acacia karroo, were used throughout the year. Throughout east-central Africa, former lowland woodland habitats have been lost to agriculture, and kudus now occur in patchy areas with suitable shrubby and forest cover and often in upland habitats. Unlike many other African antelopes, greater kudus are capable of living near human settlementif adequate cover exists.

Food and Feeding. Herbivorous browser, selecting a wide variety of shrubs, herbs, succulents, fallen fruits, tubers, and flowers. Kudus can reach food that is about two meters above the ground, and Zambezi Kudustypically spent 33% of their foraging time eating food at heights of 1-2-1-7 m. Given their size, they require large quantities of food; stomach contents from harvested individuals can weigh 30-38 kg. In Kruger National Park and Nylsvley Nature Reserve, South Africa, parts of more than 60 plant species are eaten, with variable selection of forage classes depending on season and location—both a reflection of availability. Kudus often eat plant parts that have structural and chemical defenses with no ill effects, and relative to availability, herbaceous species are the most preferred. Early in the growing season in Kruger and Nylsvley, 63-66% of feeding time was spent eating woody browse (e.g. Grewia, Dichrostachys, and Combretum), 17-37% eating herbaceous species (e.g. Schkuhria, Chenopodium, and Bidens), and 0-13% eating fruits/pods (e.g. Strychnos and Acacia). Late in the growing season, in contrast, only 30% of feeding time in Kruger was spent eating woody browse and 60% eating herbaceous species. Time spent feeding on grasses peaked at 14% late in the growing season in Nylsvley but was 0-6% at other times ofthe year in both areas. Evergreen and semi-evergreen woody browse species (e.g. Strychnos pungens and Rhus leptodictya), even those considered to be unpalatable, were important dietary components late in the dry season when other forages were limited in availability and quality. In Zimbabwe, fallen seed pods of five Acacia species were preferred over unripe seed pods still on the trees. Although Zambezi Kudus are not normally dependent on standing water, obtaining the water they need in the vegetation they eat, they will drink as they can during very dry periods.

Breeding. Zambezi Kudus are seasonal breeders. The breeding and birthing seasons in northern Zimbabwe occur in May-August and January-April, respectively, with births coinciding with the growing season. The majority of births occur more narrowly in January-February (85%) in Kruger National Park, South Africa, and February-March in southern Zimbabwe. Males establish an age-based dominance hierarchy and live in loose all-male groups outside the breeding season. Aggressive interactions between mature males appear to be rare, and they do not charge each other. Mature males assess each other’s strength by lateral displays and by pushing and twisting with their hornslaid together lengthwise and the spirals engaged. Males occasionally lock horns so tightly that they eventually die. Males 6-7 years old dominate courtship and mating; females generally are not receptive to the advances of young males. Mature males tend to associate with a particular stable female group, but there is no indication of territoriality or harem formation, and they will switch between groups of females. Mature males tend estrous females closely, frequently testing their urine with a lip curl, directing their movements, and sometimes separating them from their group. While courting, a tending male will grunt, cluck, and whine while rubbing his head and body along the female’s body and eventually pressing his neck across hers, pushing down her head. Prior to copulation, the male rests his head on the female’s rump, a behavior typical of tragelaphines. He may try to halt a female’s attempt to flee with a lateral display. After a gestation period of about nine months, a single offspring is born. Neonates are hidden for two weeks, after which they join their mother’s social group during the day; they continue to hide for 4-5 weeks during the night. The average nursing time is 6-7 minutes, and offspring are weaned at about six months. Offspring are groomed by their mother and other female group members. In Kruger National Park, males have a higher mortality rate than females; a mature male at six years old has only a 50% chance of surviving another year and most males die by the age of nine; females may live 15 years. Sex ratios as low as 15 males:100 females have been reported. High male mortality seems to be more a result of periodic malnutrition, coupled with the demands of a large body size, and male-biased predation by Lions (Panthera leo) than the costs of intrasexual competition during rut or the hazards of male dispersal. Spotted Hyenas (Crocuta crocuta) differentially prey on female Zambezi Kudus in Limpopo Province, South Africa. African Wild Dogs (Lycaon pictus), Cheetahs (Acinonyx jubatus), and Leopards (P. pardus) also prey on kudus—the latter two mostly on subadult females andjuveniles. Overall survival rates also are affected by rainfall patterns and density.

Activity patterns. As with other ruminants, alternating patterns of feeding and resting/ ruminating typify the daily activities of greater kudus, and given theirsize, they spend a considerable amount of time foraging. In Kruger National Park, throughout the year, female Zambezi Kudus are active 73% of the time and spend 50-58% of the 24hour cycle foraging, about 45% of that at night. Moving, standing alert, and grooming/ excreting waste occupy 14%, 11%, and 1% of their time. During the dry season, when forage availability can decrease by 75%, Zambezi Kudus increase their time spent moving, to secure adequate intake of food, and decrease their time spent in other activities; 85% of their time can be spent foraging and seeking food. Woodlands and shrub thickets are important for cover during hot, dry weather. As ambient temperatures increase, foraging time decreases, particularly for adult females and subadults of both sexes. Temperatures above 36°C in the wet season and 30°C in the dry season restrict foraging times.

Movements, Home range and Social organization. Female Zambezi Kudus move across savanna habitats and the transition between savannas and adjacent hills in Kruger National Park during the rainy season, but males confine their activities to riverine areas throughout the year. Females return to riverine areas where forage is most abundant during the dry season. Density estimates range from 0-87 ind/km? in Northern Cape Province, South Africa, to 3-2 ind/km? in Kruger National Park, South Africa. Home ranges of females were 3-6-5-2 km? at Kruger, and males occupy areas greater than 11 km? Home ranges of mature males were not exclusive of other males’ home ranges, and they typically overlapped several home ranges of female groups. Groups of 2—4 adult females are typical throughout the year, and males are often found in larger groups of up to ten individuals during the non-breeding season. Occasionally, larger aggregations are observed. All greater kudus rely on cryptic coloration and coat patterning and typically freeze in protective cover in the face of a threat; if fleeing, they are capable of jumping 2-5 m. Greater kudus have one of the loudest alarm barks among the African antelopes.

Status and Conservation. Classified as Least Concern on The IUCN Red List (under Tragelaphus strepsiceros ); it does not differentiate the four species of greater kudu identified here. In the late 1990s, the number of greater kudus rangewide was estimated at about 482,000, with 15% in protected areas and 61% on private land. All greater kudu species are threatened by human encroachment and associated habitat modifications (dryland and subsistence farming), excessive cattle grazing, disease transmission from cattle (rinderpest has been particularly hard on greater kudus), and poaching. Although numbers are greatly reduced from historic levels and populations are widespread, the species group is considered stable. Because all greater kudus are highly prized as hunting trophies, private-land management plays an essential role in their conservation. Their horns also have been used in various ways: as symbols of male potency, as containers, musical instruments, and as religious artifacts. Significant and well-studied populations occur in Kruger National Park and Nylsvley Nature Reserve, South Africa.

Bibliography. Bro-Jorgensen (2008), Cooper & Owen-Smith (1986), Cronje et al. (2002), Dasmann & Mossman (1962), Dorgeloh (2001), East (1999), Estes (1991a, 1991b), Fabricius & Mentis (1992), Groves & Grubb (2011), Huffman (2004r), IUCN/SSC Antelope Specialist Group (2008bj), Kingdon (1982), Lydekker & Blaine (1914), Nersting & Arctander (2001), Owen-Smith (1977, 1979, 1982, 1984a, 1984b, 1985, 1990, 1993a, 1993b, 1994, 1997, 1998, 2000), Owen-Smith & Cooper (1983, 1985, 1987), Simpson (1968), du Toit (1990a, 1990b, 1995), Underwood (1978), van der Waal et al. (2003), Wilson (1965).

Figures

On following pages: 35. Cape Kudu (Strepsiceros strepsiceros); 36. Zambezi Kudu (Strepsiceros zambesiensis); 37. Northern Kudu (Strepsiceros chora); 38. Western Kudu (Strepsiceros cotton); 39. Common Eland (Taurotragus oryx); 40. Giant Eland (Taurotragus derbianus).

Distribution. Tanzania (not extreme NW), extreme S DR Congo , Malawi , Mozambique , Zambia (not extreme N), S Angola , Namibia , Botswana , Zimbabwe , Swaziland , and N South Africa . Demarcation of the distribution between the Zambezi Kudu and the Northern Kudu ( S. chora ) in S Kenya and N Tanzania requires additional research.