African elephants, the earth's largest land animals, can grow up to 11 feet at the shoulder, have an average length of 20-24.5 feet and weigh more than six tons. Their potential life span is 60 years, but today only about 20 percent survive to reach 30.
Subspecies: There are two subspecies of African elephant: the savanna or bush elephant and the forest elephant. An estimated 600,000 of them remain in the 2.7 million square miles of savanna and rainforest south of the Sahara. This is less than half the number of elephants surviving ten years ago. More than half the continent's elephants live in the rainforests of West and Central Africa where they receive better protection than on open savanna.
What do they eat? Elephants eat as much as 300 lbs. of food during an 18 to 20 hour elephant-day, yet half of the food leaves the body undigested. Their diet consists of grasses, roots, bark and woody parts of trees. They drink large quantities of water--19-24 gallons per day. During a drought, they will dig holes with their trunks and tusks in dry riverbeds to find water.
Physical Characteristics: Both male and female African elephants have tusks which can be straight or curved upward. Tusks are elongated upper incisor teeth which first appear at age two. The ivory tusks are a unique mixture of dentine, cartilaginous material and calcium salts. They continue to grow throughout an elephant's life, and are used when feeding, in social encounters as instruments of display, or as weapons.
African elephants have saddle backs, two "fingers" at the tips of their trunks and single-domed foreheads. (In contrast, Asian elephants have rounded backs, single "fingers" and double-domed heads, as well as smaller ears; only males have tusks.)
An elephant's skin is sensitive, requiring frequent bathing, massaging and powdering with dust to remain parasite and disease free. The trunk, formed from the elongated nose and upper lip, enables the tall elephant to feed on vegetation on the ground as well as on trees. The trunk is also used for drinking--by sucking up water and squirting it into the mouth--greeting, caressing, threatening and throwing dust on itself. The trunk muscles give it flexibility as well as strength, enabling it to carry, with the same ease, a tree or a coin. The nostrils are located at the tip of the trunk.
Many physical characteristics of the elephant are adapted to body size. The large skull, for example, supports the trunk, enormous molars and tusks. Huge ears help the elephant lose body heat. The large surface area of the feet support its weight, and the soft elastic layers which form the sole expand beneath the weight of the animal as it walks, absorbing the considerable burden.
Elephant populations: Elephants form family units of two or three sisters, or a mother and daughters, and their offspring. Female young remain within the family, even after reaching maturity, and breed. As the unit grows in size, a subgroup of young cows will separate and form its own unit. Males leave the family at puberty and can form temporary transient groups. Generally, however, males live alone with few social bonds.
Most elephant populations reproduce according to the seasonal availability of food and water. During the dry season, the population suffers a period of nutritional stress and cows cease to ovulate. When the rains break and the food supply improves, a period of one to two months of good feeding is needed to raise the female's body fat above the levels necessary for ovulation. Thus, female elephants are in heat the second half of the rainy season and the first few months of the dry season.
Mating and Birthing: During the mating season each female may be in heat for only a few days, so the distribution of sexually reproductive cows is constantly fluctuating. Bulls must travel long distances in order to monitor the changing reproductive status of cows within their range.
The gestation period is 22 months. The long pregnancy means the infant is born during the wet season when conditions are optimal for survival. At birth, the average weight of the African elephant calf is 265 lbs. There is also a long period of juvenile dependency. The infant elephant suckles--with the mouth, not the trunk--from the paired breasts between the mother's forelegs for three to four years.
Once the cow starts to breed, she may produce an infant every three or four years. The period of greatest female fertility is between ages of 25-45. Male elephants aged 30 or older are able to successfully compete to mate with females.
Elephants aid injured companions even in the face of considerable danger. The matriarch of a family will flap her ears as a signal to others to form a defensive, protective position around calves. They communicate with each other using low frequency sound (infrasound) which can be heard up to six miles. This infrasound is at frequencies too low for humans to hear.
Scientists consider the African elephant a "threatened" species.