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Sculptures by Phyllis Bone


ORDER PROBOSCIDEA: ELEPHANTS

Two extant species:

Loxodonta africana - the African elephant.

Elephas maximus - the Indian elephant.

Proboscids were once found across most of the globe. Many extinct elephants shared the typical features as the surviving types. Until the end of the last ice age there were a further 6 elephant species, including the mastodon Cuvieronius, which was driven to extinction perhaps within the last 2,000 years.

The large size of proboscids probably evolved in response to competition with the perissodactyls (also hind-gut fermenters)

An African elephant (Loxodonta africana).

 

ELEPHANT TEETH

Aside from the tusks (modified second incisors) there are only three molars and three milk pre-molars. Uniquely, in the elephants only four of these are exposed at once (one per half jaw). Each will be replaced throughout life by five others, being pushed forward as they become worn down.

The teeth are very hypsodont (ridged), especially the later teeth. The grinding surface consists of enamel, dentine and cement. These wear at different rates so the surface is never worn smooth.

XH15-3.1: Loxodonta africana skull

The skull of this juvenile African elephant shows features typical of the elephants and mammoths which became extinct so recently. The skull is very 'solid' and heavy. Both jaws are deep to accomodate the huge teeth. They are also very short for such a large animal. The nasal opening is mounted high on the forehead and shows where the trunk (a grossly elongated, prehensile upper lip and nose) terminates at the skull.

The trunk is used for smelling, touching, as a snorkel when submerged, to drink, squirt water & greet other elephants.

Some African elephants do not live on the savannah but in the forests of Africa. It was from here that Loxodonta spread onto the plains after the other elephant genus, Elephas, became extinct in Africa. Forest elephants are a separate subspecies.

 

Elephas maximus feet.

XH15-2.2 Elephas maximus fore foot.

Both the fore-foot (XH15-2.2) and the hind-foot (XH15-2.3) of the Indian elephant are five toed. These feet must support an enormous weight, and so there has been no reduction in the number of digits. Instead, the foot is broad, and rests on a pad of fatty tissue and fibres (see diagram). The hooves are nail-like (as can be seen on the dried hind foot - XH15-2.1). Although the legs are strong and pillar-like (with a long humerus and femur but short distal segments) to support the elephant's weight, it can charge at 25mph for short bursts.

XH15-2.3 Elephas maximus hind foot.

 

TUSKS

Tusks are used for digging, scraping and as weapons. They grow continuously, from their appearance at 2 years until death, reaching 3.5 metres in Loxodonta bulls. Such large bulls have become rare as a consequence of ivory poaching, a trade which threatens all elephants more even than habitat destruction.