Elephant

I

Introduction

Elephant, huge mammal characterized by a long muscular snout and two long, curved tusks. Highly intelligent and strong, elephants are the largest land animals and are among the longest lived, with life spans of 60 years or more. Healthy, full-grown elephants have no natural enemies other than humans.

Throughout history, people have prized elephants for their great size and strength. On the battlefield, soldiers astride elephants have trampled and terrified enemies. Elephants also have been trained to carry heavy supplies through jungles and to haul huge logs from the forests where they once lived.

Elephants have long been revered and honored, and in Thailand, India, and other Southeast Asian countries, beautifully decorated elephants still play a significant role in traditional religious ceremonies. According to Buddhist tradition, the Buddha chose the form of a white elephant as one of his many earthly incarnations, and the rare appearance of a white elephant is still heralded as a manifestation of the gods.

Over the past 40 million years, more than 600 species of elephants have roamed the earth. Today only three species remain—the savanna elephant and the forest elephant of Africa, and the Asian elephant. Climate fluctuations over the millennia and resulting vegetation changes caused the extinction of many elephant species, but human impact has also taken its toll. At the turn of the 20th century, elephants numbered from 5 million to 10 million, but widespread hunting and habitat destruction reduced their numbers to 400,000 to 500,000 by the end of the century. Present-day efforts to save elephants may be inadequate, and biologists are unsure if elephants as a species will survive.

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II

Evolution

The earliest known ancestors of modern-day elephants evolved about 65 million years ago in the region now known as Egypt. Called Moeritherium, these swamp-dwelling animals were from pig- to cow-sized, with an elongated snout but no trunk. They sported two pairs of slightly elongated front teeth—indicators of what would eventually evolve into tusks. Three groups of elephant-like animals descended from Moeritherium: Deinotherioidea, Mastodontoidea, and Elephantoidea. Deinotherioidea evolved from 54 million to 38 million years ago and lived in parts of Asia, Europe, and Africa. It possessed a trunk and two tusks, which pointed backward, possibly for hoeing up food from the edges and bottoms of swamps. The last surviving members of this group died out about 10,000 years ago.

The earliest members of the Mastodontoidea group evolved about 38 million years ago. These animals had elephant-like trunks, and, depending on the family, displayed either two or four tusks. The upper tusks were vertical, or upward pointing. The lower set, when present, bent forward and were sometimes shaped like shovels, apparently for digging plant roots and bulbs. The mastodon, the most familiar member of this group, evolved about 15 million years ago, and spread to Europe, Asia, Africa, and North America. Its descendants lived in the cold world of the last great Ice Age—2.5 million to 8,000 years ago, when thick glaciers covered parts of North America and Europe. The mastodon had two tusks that curved upward and was covered with a thick coat of shaggy hair. About 10,000 years ago, early humans began hunting mastodons, contributing to their extinction.

The Elephantoidea group, which evolved 8 million to 10 million years ago, includes the mammoth and Stegolophodon. The mammoth also lived during the Ice Age and was covered with a thick, woolly coat. Unlike the mastodon’s forward-curving tusks, the mammoth’s tusks curved backward. The mammoth displayed a prominent hump on its back. Mammoths roamed North America, Africa, Europe, and Asia, were hunted by early humans, and died out about 8,000 years ago. Stegolophodon evolved about the same time as the mammoth and inhabited Europe, Asia, and Africa. Its tusks and other features were intermediate between the mammoth and modern-day elephants. Stegolophodon’s descendants are the African and Asian elephants of today.

III

Range and Habitat

Fossils of elephant ancestors indicate they once lived on every continent except Australia and Antarctica, but elephant habitat today is restricted to Africa and parts of Southeast Asia. Elephants occupy an array of environments in Africa and Southeast Asia—grasslands, marshes, forests, deserts, and mountains. They are herbivores, or plant eaters, and need great quantities of food to sustain their massive size. They also need a lot of drinking water and so are restricted to areas with ample vegetation and adequate water.

Even small herds of a few elephants can quickly deplete the food and water resources of an area, forcing them to keep on the move. A herd of elephants migrates seasonally in an extended loop, looking for fresh resources within its home range, which can extend over 1,500 sq km (600 sq mi). In its search for food, an elephant can travel 5,000 to 10,000 km (3,100 to 6,200 mi) in one year, the longest mammal migration on record.

IV

Physical Description

The three species of elephants look alike, but they have small differences in size, color, and other physical characteristics. The savanna elephant is larger than the forest elephant and the Asian elephant. Males, or bulls, may reach 4 m (13 ft) in height and weigh up to 7,000 kg (15,400 lb). Females, or cows, are shorter, averaging 2.8 m (9 ft) in height, and weigh considerably less, about 3,600 kg (7,900 lb). Savanna elephants are light gray in color, although they can appear dark gray, red, or brown from the mud they bathe in. They have a low, flat forehead and a slightly swayed back. Their massive ears drape over their shoulders and come to a point at the bottom. The ears average 1.5 m (5 ft) in length and 1.2 m (4 ft) in width. Both bulls and cows have long, thick, curved tusks.

Forest elephants are smaller than savanna elephants. Bulls reach about 2.5 m (8 ft) in height and weigh about 900 kg (2,000 lb). Cows are only slightly smaller. Forest elephants also have large ears, but they are completely rounded in a fan shape. Forest elephants are a dark gray color. Bulls and cows have long, narrow, straight tusks and the ivory color is tinged with pink.

Asian elephants are shorter and stockier than their African relatives, with ears that do not reach their shoulders. The Asian bull stands 2 to 3.5 m (7 to 11.5 ft) tall and weighs 2,000 to 5,000 kg (4,000 to 10,000 lb). Cows reach an average height of 2.4 m (7.8 ft) and weigh an average of 3,000 kg (6,600 lb). Asian elephants have dark gray skin, a bulbous forehead, and a rounded back. Ear size averages 0.75 m (2.5 ft) long and 0.6 m (2 ft wide). The cow’s tusks may be either absent or undeveloped.

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