Taurotragus derbianus (Gray, 1847)

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 : 617-618

40.

Giant Eland

Taurotragus derbianus

French: Eland de Derby / German: Riesenelen / Spanish: Eland de Derby

Other common names: Derby Eland, Lord Derby's Eland; Eastern Giant Eland (gigas), Western Giant Eland (derbianus)

Taxonomy. Boselaphus derbianus Gray, 1847 ,

Senegambia, W Africa.

The two eland species are separated taxonomically from related Strepsiceros species because they have very large supraorbital foramina in very deep, wide, and elongated depressions; their mesopterygoid fossa form a wide U-shape; and the ends of the parocciptal processes are short and free. Although IUCN and others recognize two subspecies of the Giant Eland ( derbianus , “Western Giant Eland,” and gigas , “Eastern Giant Eland”), recent univariate and multivariate morphometric analyses failed to demonstrate any consistent separation in geographic samples; therefore it is considered monotypic here.

Distribution. Restricted to three disjunct populations in SE Senegal, N Guinea, and SW Mali, and perhaps E Guinea-Bissau; N Cameroon, SW Chad, and maybe E & C Nigeria; and Central African Republic, SE Chad, SW Sudan, and maybe NE DR Congo and NW Uganda.

Descriptive notes. Head-body 290 cm (males) and 220 cm (females), tail 90 cm, shoulder height 150-176 cm; weight 440— 950 kg (males) and 440 kg (females). The common name Giant Eland is misleading, because it is generally smaller in mass than the Common Eland ( 7. oryx ); the name refers to the spiraled horns of the Giant Eland, which are 80-123 cm in length and form a V-shape. Male Giant Elands are heavier and have longer horns and dewlaps than females; otherwise, the sexes are similar. The smooth pelage of both sexes is strikingly reddish-brown, chestnut, or sandy (males tend to turn gray as they age) and highlighted by a short brown to black spinal mane from the neck to the middle of the back and vertical white stripes on the torso. The stripes are often obvious on the hindquarters as well. Individuals in the one western population tend to be smaller and richer in color and have 14-15 white stripes vs. twelve white stripes in the two eastern populations. The lips are white, with several white dots along the jaw, and the bridge of the nose is black with a tan chevron between the eyes. Males develop a chocolate to reddish fulvous tuft of hair on their nose (nasal brush) as they age. In contrast to the tufted dewlap of the Common Eland, which begins on the throat, the fringed dewlap of the Giant Eland begins under the chin and ends about mid-neck, with an upward sweep of dark hair forming a collar. Both eland species have a shoulder hump, but it tends to be more obvious in the Giant Eland in part because of the dark collar reaching up to the anterior beginning of the hump. The chest and inside of the legs are white, but the belly has a black stripe from front to back. The legs are relatively slender; all four have two separate garters of white and blackjust about the hooves, and the upper forelegs have a posterior black spot. The ears are larger and more rounded than those of the Common Eland. Dental formulais10/3, C0/1,P 3/3, M 3/3 (x2) = 32. Diploid numbers for the Giant Eland are 31 for males and 32 for females—the same as the Common Eland and among the lowest of the Tragelaphini .

Habitat. The Giant Eland is more constrained in its habitat preference than the Common Eland. It is restricted to broad-leafed woodland savannas, often dominated by Isoberlinia doka, and forested mosaics, and it is uncommon in grassland savannas; hilly and rocky habitats are common in Giant Eland habitat. Free water is not an important habitat component, but it will drink daily if wateris available.

Food and Feeding. The Giant Eland is a browser and eats leaves, emerging shoots, herbs, and fruits and less commonly grasses. It is said to be particularly fond of the young leaves of the Isoberlinia doka tree and will use its horns to break branches and obtain forage. Shoots and flowers of Gardenia also are a favored food item. The flush of herbaceous vegetation that appears after fires is attractive to Giant Eland.

Breeding. There is no set birthing and breeding season, and young can be observed throughout the year. Breeding behavior of the Giant Eland has not been reported in detail, but it is probably comparable to the Common Eland and low-keyed. Males are not territorial but presumably establish a dominance hierarchy for breeding based on mass and horn length. Gestation is 8-9 months, and single births are the norm. In captivity, obvious signs of labor begin 85 minutes before birth, which occurs in a lying position. The neonate stands after about 45 minutes. Weaning occurs at about six months. In the wild, Lions (Panthera leo) and Spotted Hyenas (Crocuta crocuta) prey on young. Longevity is probably 15-20 years in the wild and longer in captivity.

Activity patterns. Mainly crepuscular, but likely also active at night.

Movements, Home range and Social organization. Limited ecological studies have been conducted on the Giant Eland, and no specific information is available for home range size. The distribution and availability of the tree Isoberlinia doka, a preferred forage, are said to guide the movements of the Giant Eland. Although these elands are swift, wary, and capable of speeds of 70 km /h, their regular movements are likely less extensive than those of the Common Eland, which inhabits more arid areas with less predictable food resources. The Giant Eland is gregarious, and typical group size is 10-30 individuals, but groups of 60 or more are not uncommon. Mature males are often solitary. Group sizes of the Giant Eland are stable and do not change as much seasonally as do groups of the Common Eland.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Giant Eland once ranged in a continuous band across Central Africa from Gambia to the White Nile. It is now extinct in Ivory Coast, Gambia, Ghana, and Togo. The total population of Giant Eland is estimated at only 15,000 -20,000, but is considered stable over parts of its remnant range, particularly in Cameroon and Central African Republic, where human densities are low but political instability can be high, hampering conservation activities. Only 200 or fewer Giant Elands occur in West Africa, most in Niokolo-Koba National Park, Senegal. Individuals from Niokolo-Koba were captured and moved to two other facilities in Senegal, Bandia Reserve in 2000 and later Fathala Reserve, with a goal of breeding them to establish new populations; 30 captive births occurred in 2000-2006. Giant Elands are highly prized as trophies because of their splendid long and spiraled horns, affording opportunities for enhanced conservation through controlled hunting. Loss of habitat from an expanding human population and poaching are ongoing conservation challenges.

Bibliography. Antoninova, Hejcmanova et al. (2006), Antoninovéa, Nezerkova et al. (2004), Bro-Jorgensen (1997), Cotton (1933), Dorst & Dandelot (1993), East (1999), Estes (1991a, 1991b), Happold (1987), Huffman (2004m), IUCN/SSC Antelope Specialist Group (2008bj), Kingdon (1982, 1997), Lindsey et al. (2006), Lydekker & Blaine (1914), Nezerkovéa & Hajek (2000), Nezerkova et al. (2004), Nowak (1999), Rubes et al. (2008), Spinage (1986), Walther (1990c), Weigl (2005).

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. Restricted to three disjunct populations in SE Senegal , N Guinea , and SW Mali , and perhaps E Guinea-Bissau ; N Cameroon , SW Chad , and maybe E & C Nigeria ; and Central African Republic , SE Chad , SW Sudan , and maybe NE DR Congo and NW Uganda .