Elephant >>

Biology - Physical Description

The African Savanna Elephant is the largest land mammal with adult males achieving body weights greater than 7 tonnes. Parker (1979), from a detailed study of ivory, showed a western race of savanna elephants extending through Angola and northern Namibia across as far west as Matabeleland in Zimbabwe. Namibia is famous for its "Desert Elephant" and, although it has now been demonstrated that these desert-dwelling animals are part of a continuous population extending to Etosha National Park, they possess adaptations not seen in other savanna elephants - large body size being one characteristic. The largest elephant recorded (from Fenykoevi in Angola in 1955) was 4 metres high and is probably from the same race as Namibia's north-western elephant.

The elephant is described as a 'Pachyderm' because of its very thick skin which may reach a thickness of 3-4cm. Although both species of African elephant have five well-formed digits on both fore and hind feet, Loxodonta africana displays 4 nails on the fore feet and 3 on the hind, whereas L. cyclotis has 5 and 4 respectively.

The name Loxodonta is derived from the lozenge-shaped teeth of the genus. During its lifetime a progression of six molars erupt from the posterior of the jaw and move along the mandibles, wearing out as they go, until they fall out. The succession of molars has allowed fairly accurate ageing of animals (Laws 1966, Sikes 1966, 1968).

Figure 4 Relationship between age and tusk size adapted from Pilgrim & Western (1986)

The tusks are elongated upper incisors consisting of a unique mixture of dentine and calcium salts which exhibits a diamond pattern in section. Elephant tusks grow throughout their lifetime (Figure 4). The largest tusks on record are from Kenya and weighed 102.3 and 97kg. In the southern African region the largest recorded pair are 64.3 and 64.8 kg from the Limpopo Valley (Best & Best 1977). Namibian ivory (from the western population) has a reputation for being hard and brittle and broken tusks are a common feature of large adult males.

Both males and females possess glands on the temporal region of the face which secrete copiously irrespective of age, sex or season (Short 1972). The discovery of 'musth' in African elephant is relatively recent (Moss 2000) and this discharge is one of the symptoms displayed by adult males in a musth condition. Musth is directly linked to reproductive behaviour and occurs in males over 29 years of age mainly during the rains and lasts for two-three months at a time.

Elephants are capable of communications over long distances using infrasound inaudible to the human ear (14-20Hz). Much of the communication is linked to females in oestrus but also plays a rôle in relaying alarm messages and maintaining contact when elephant groups are separated (Payne 1998, Charif et al 2004).

Ansell (1974) recognised four subspecies of savanna elephant but included the Kaokoveld elephant in the main type L.a. africana.

  male female
Largest: Fenykoevi - Angola 1955 400 -
Namibia: from Lindeque (1991) >350 >300
Namibia: Best & Best (1977) up to 350 -
Zimbabwe: Martin (1987) up to 340 250
Africa: Macdonald (2001) 330 270
Southern Africa: Shortridge (1934) 305-320 -
Asia (Elephas) Macdonald (2001) 250-300 -
Forest elephant: Smithers (1983) 235 210
Table 1: Shoulder heights for elephant

 

 

 

Martin (2005) took the body length and age data for Etosha from Lindeque (1991) and applied the formula from Chase (et al 2003) to derive shoulder heights for these elephants. Lindeque's data only extends up to age classes of 30 years but, in these classes, the indications are that both males and females are at least 10% taller than the Kruger National Park elephants. Applying this ratio to the oldest animals in the population suggests that shoulder heights over 3.5 metres would be expected.

 

Sexing of adult elephants

Field experts and authors of books on African elephants will advise that male elephants are taller than females; that they have thicker tusks; that the foreheads of adult females are pointed whereas those of males are sloping; that the back and belly of a male elephant slopes downwards towards the hind legs whereas in the profile of a female these features are more horizontal; and that the shape of the prepuce in the adult male forms an abrupt right angle with the belly whereas the vulva of a female has a triangular profile (Figure 5).

The presence of mammary glands is limited to females only. Although males have vestigial nipples, they lack the pronounced swelling between the forelegs. The mammary glands can be detected in all views of a female elephant (except perhaps from dead astern). The belly of an adult female dips downwards immediately behind the forelegs and the skin of the mammary gland is paler than the belly skin.