Elephant

I

Introduction

Elephant, largest living land mammal, which during the Pleistocene Epoch (1.6 million to 10,000 years ago; see Quaternary Period) roamed every land mass except Australia and Antarctica. Two surviving species, the Indian elephant, of India and south-eastern Asia, and the African elephant, ranging south of the Sahara, are now limited to tropical forests, savannahs, deserts, and river valleys. The Indian elephant reaches heights of 3 m (10 ft) and the African elephant, 4 m (13 ft). Earlier members of this group—the mammoths, some of which reached 4.5 m (15 ft) in height, and the smaller mastodons—survived up to the time of the Palaeolithic (Stone Age) humans, whose cave drawings depicted woolly mammoths.

II

The Trunk

The boneless, muscular trunk, the most distinctive feature of elephants, is actually a greatly elongated upper lip and nose used to convey grasses, leaves, roots, fruits, and water to the mouth. Present-day elephants consume as much as 200 kg (441 lb) of forage a day in this manner and drink as much as 190 litres (50 gallons) of water, drawing it through their nostrils and squirting it into the mouth. An extremely versatile organ, the trunk is also used to trumpet calls, pull down trees, rip off foliage, and draw up dust for dust bathing. It is also a highly sensitive organ, which the animals raise into the air to detect wind-borne scents. By means of finger-like lobes on the end of the trunk and by the sucking action of the two nostrils, elephants can pick up and examine small objects.

III

Tusks and Teeth

The tusks, which are deeply embedded in the skull, are actually enormously enlarged upper incisor teeth and grow throughout the animal's life. Record tusks of the male African elephant measured 3.5 m (11 ft) long. Elephants have only four molar or grinding teeth, one to each side of the upper and lower jaws; each is a massive plate about 30 cm (12 in) long and 10 cm (4 in) wide. When worn down by the coarse vegetation that elephants eat, these teeth are replaced by larger ones that shift forwards from the rear of the jaws. At about 40 years of age, the animal's final and largest molars come into position and last for about 20 years. Elephants' lifespans are comparable to those of humans.

IV

Skin

An elephant's skin is wrinkled and hangs in folds. Although it is as much as 3 cm (1 in) thick, it is quite sensitive. It has a sparse covering of hair and no moisturizing glands or sweat glands. To cool down, an elephant must flap its ears or use its trunk to spray water. Rolling in mud also helps to keep them cool as the mud dries on their skin and protects it from the sun. Elephants have dust baths to keep the skin in good condition and free of parasites.