ELEPHANT/TEMBO

Elephants have four teeth, all molars, which have jagged ridges for grinding leaves, stems, and roots. A single tooth can weigh more than 5 kg (11 lb) and measure 30 cm (12 in) in length. The first pair of molars is located toward the front of the mouth. When these front molars wear down, they drop out in pieces as the two molars in the back shift forward. Two new molars then emerge in the back of the mouth to replace those that have moved forward. Elephants replace the back molars six times throughout life. When the last set of molars wears out—anywhere between 40 and about 60 years of age—an elephant can no longer chew food and dies of starvation, a not uncommon death among elephants. Elephant tusks are actually a pair of elongated teeth. They are the largest and heaviest teeth of any living animal. The tusks are used for digging for roots and water, stripping the bark off trees for food, fighting each other during mating season, and, in savanna and forest elephant cows, warding off predators of baby elephants such as lions and tigers. In a calf, the first incisors are replaced within 6 to 12 months of birth. The second set, which become the tusks, grows at the rate of about 17 cm (about 7 in) per year throughout life. Tusk growth is determined by genetics and nutrition, and over the years, normal wear and tear scales down their length. A bull tusk from a savanna or forest elephant typically weighs 20 to 45 kg (50 to 100 lb) and is 1.8 to 2.4 m (6 to 8 ft) in length. The tusks of an adult Asian bull average 1.5 m (5 ft) in length and 30 kg (70 lb) in weight. Ivory hunters prefer to target savanna and forest elephants because their tusks are more massive than Asian elephants, and both bulls and cows have tusks. E.Skin Elephant skin is wrinkled and about 2.5 cm (1 in) thick, with a sparse covering of bristle-like hair. Despite its thickness, the skin is subject to infection by lice, ticks that carry blood-borne diseases, and the larvae of the warble fly, which bore into the elephant’s body and cause swelling and bleeding. Elephants frequently cover themselves with dust, bathe in water, and take mud baths to protect their skin. F.Senses Elephant eyesight is poor, and the eyes are small in relation to the enormous head, which can turn just slightly from side to side. This limited movement results in restricted side vision, and an elephant must move its whole body to broaden its range of vision. Its other senses—hearing, smell, taste, and touch—are acute. The most sensitive organ is the trunk, which is frequently at work picking up scents of food and danger from the ground and air. Elephants can smell water at great distances and can hear certain sounds from more than a mile away. Sexual maturity among bulls begins at about 11 to 12 years, but during mating season older bulls drive the younger ones away; bulls typically do not mate until around age 30. When a bull is about 20 to 25 years of age, the large glands on both sides of its head begin to swell and secrete an oily, testosterone-rich fluid. The bull's behavior becomes erratic and often aggressive toward other bulls and humans at this time. This event, known as musth, occurs annually throughout the bull’s lifetime, lasting for several days or several months depending on the animal's age and overall health. Cows begin breeding at about nine years of age and typically come into estrus, or heat, every 16 weeks, at which time they are receptive to mating. While pregnant, a cow’s estrus cycle halts and she does not mate. Soon after a cow gives birth, her estrus cycle begins again and she mates even if she is nursing. There is no breeding season for elephants—mating occurs throughout the year. Elephants do not mate for life. Bulls and cows form temporary pairs prior to mating, and after a brief courtship, the bull mounts the cow from behind, copulating for less than a minute. Mating may continue for several days. Usually, one bull mates with several cows, guarding them from the advances of other bulls. Cows give birth to single calves 20 to 22 months after conception, the longest gestation period known for any animal. Cows may give birth alone or surrounded by other cows. A newborn elephant is about 1 m (about 3 ft) high and weighs about 120 kg (about 260 lb). The calf is initially helpless and unable to control its leg muscles and trunk. After one to two hours, the calf is able to stand and suckle, obtaining milk from its mother’s paired mammary glands, which are located between the front legs. Between three and four weeks, calves begin to experiment with feeding themselves; it may take six months before a calf can master the skill of drinking with its trunk. By the age of nine months, calves spend almost half of their time feeding on vegetation. They are weaned at about three or four years of age upon the birth of a younger brother or sister. In captivity, cows have borne calves until they are 60 years of age, at intervals of about four years. One or more female elephants, known as allomothers, often assist in the rearing of a calf. Allomothers stay near the calf, for example, while the mother moves away to forage for food. The more allomothers in a family, the greater the chances of the calf's survival. By age ten, a calf will weigh 900 to 1,300 kg (2,000 to 3,000 lb). It will attain most of its height between the ages of 20 and 25, but unlike other mammals, will continue to grow at a slow rate throughout life