Sunday, 1 May 2011

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Elephants

Gentle Giants

Elephants are the largest land animals. They can weigh over 6,000 kg, or more than the weight of four cars! The one feature that makes an elephant unmistakable is its long trunk. A trunk is an elephant's best tool for sucking up water, digging, grabbing, lifting, sniffing, and breathing. The trunk even has a fingerlike tip that can flick dirt from an elephant’s eye or pick up a single blade of grass. There are threespecies of elephants. Two species live in Africa and one lives in Asia. All three species are endangered.
Elephants use their trunks like an extra hand, arm and fingers. They can work with objects as large as trees and as small as a berry.
Elephants use their trunks like an extra hand, arm and fingers. They can work with objects as large as trees and as small as a berry.
©G.Ellis/GLOBIO.org

Elephants Through the Ages

Elephant-like creatures first appeared on Earth millions of years ago. More than 600 different species of elephant have existed. Some early elephant ancestors were smaller than modern elephants. Elephant-like animals of the genus Moeritherium, for example, were about the size of a large pig. They had very small tusks, tiny ears, and no trunk. They lived about 36 million to 50 million years ago. Mammoths and mastodons were more recent elephant relatives. Some were about the same size and shape as modern elephants but had much longer tusks. Those that lived in cold climates had thick fur. Mammoths and mastodons became extinct about 10,000 years ago.

The (Very) Big Three

There are two species of African elephants. The savanna elephant is found only in eastern and southern Africa and lives in savannawoodlands and grasslands. The other African elephant, the forest elephant, lives in the tropical forest regions of western Africa. The Asian elephant lives only in the tropical forests of Asia. Looking at an elephant’s physical features is the best way to tell which continent it comes from.

Savanna Elephants

Savanna elephants have a swaybacked shape and enormous fan-shaped ears that reach past their shoulders. They have domed foreheads with one bump. Their trunks have “lips” on the upper and lower tip. Males reach a shoulder height of 3-4 m and weigh, on average, about 5,000 kg. Some of the largest males weigh more than 6,000 kg. Females average 2.5 m in height and weigh about2,800 kg. Savanna elephants have tusks that are long, thick, and slightly curved.

Forest Elephants

Like savanna elephants, forest elephants have a swaybacked shape and large ears, but their ears are rounder. They have domed foreheads with one bump. Their trunks have lips on the upper and lower tip. Both male and female forest elephants are about the same size—about 1.6-2.8 m in height. Males weigh 2,000 kg to 4,500 kg. Females may weigh up to 3,000 kg. Forest elephants have tusks that are narrow and straight.
Asian elephants have a distinctly different look from African elephants—smaller ears and face and two lumps on their head.
Asian elephants have a distinctly different look from African elephants—smaller ears and face and two lumps on their head.
©G.Ellis/GLOBIO.org

Asian Elephants

Asian elephants have an arched body shape. They have triangular ears that do not reach their shoulders and two bumps on their foreheads. Their trunks have a single lip on the upper tip of the trunk. Male Asian elephants are 2-3.5 m tall. Their average weight is about 5,400 kg. Females average about 2.35 m tall and weigh about2,700 kg. Often, only males have tusks.

Elephant Anatomy

Elephants’ bodies have many useful adaptations. Perhaps the most interesting is the trunk, which can perform functions ranging from that of a drinking straw to a forklift! African elephants and some Asian elephants have a pair of tusks—two large, heavy incisor teeth made of ivory.
Elephants depend on all their senses—hearing, smell, taste, touch, and sight. Elephants can smell water that is very far away. They also have excellent hearing. An elephant can hear certain sounds that are several kilometers away. Touch is also very important to elephants. Their trunks are especially sensitive to touch. Elephants have small eyes and rather poor eyesight. An elephant will often swing its head from side to side to get a better look at something.

Herds

Deep water—no problem, elephants are good swimmers. Wetlands like swamps provide herds with water to bathe in, drink and many green plants to eat.
Deep water—no problem, elephants are good swimmers. Wetlands like swamps provide herds with water to bathe in, drink and many green plants to eat.
©G.Ellis/GLOBIO.org
Elephants live in social groups calledherds. Herds usually have about 10 to 20 members. Sometimes many herds will meet and form “super herds” of 100 or more elephants. Herds consist mainly of females that are related to each other. A typical herd might include mothers, daughters, aunts, and grandmothers, and a few young males. The oldest female is the herd’s matriarch. She leads the herd to water and finds food and a place to rest. There are also smaller bachelor herds that are made up of adult males.

Baby Elephant Walk

Females start to breed when they are about 13-years-old. Usually, they mate with a male who is at least 30-years-old. After a female becomes pregnant, there is a gestation period of 22 to 24 months before the baby elephant, or calf, is born. A newborn calf is about 1 m tall and weighs about 80 kg—roughly the same weight as an average male adult human! The calf begins to walk within a few hours of its birth.
Most elephants have one baby at a time, but taking care of just one baby is still a lot of work. Like all babies, this calf begs mom to feed it. Elephant calves drink over 11 liters (3 gallons) of milk a day!
Most elephants have one baby at a time, but taking care of just one baby is still a lot of work. Like all babies, this calf begs mom to feed it. Elephant calves drink over 11 liters (3 gallons) of milk a day!
©G.Ellis/GLOBIO.org

The Early Years

The females of the herd protect the calves. They offer shade from the hot sun to the newborns, chasepredators away, and help the calves if they stray or become stuck in mud. Calves drink their mother’s milk until they are about two years old. Grass and tender plants are the first solid foods calves eat.

Some Stay and Some Go

Young male elephants leave to join a bachelor herd when they are about 11-years-old. Female elephants, however, stay with their mother’s herd for life. Elephants keep growing their whole lives. A male may grow to be twice as large as a female of the same age. In the wild, elephants live to be about 60-years-old.

An Elephant-sized Appetite

Elephants are herbivores. They eat grasses and shrubs as well as the roots, fruit, bark, twigs, and leaves from trees. Because they are such large animals, elephants need to eat and drink a lot. Each day, a full-grown elephant eats at least 100 kg of food and drinks as much200 l of water.
Regardless of the environment, elephants need water and must find it every few days to survive. A trunk is the perfect tool to suck up a few buckets full of water at a time!
Regardless of the environment, elephants need water and must find it every few days to survive. A trunk is the perfect tool to suck up a few buckets full of water at a time!
©G.Ellis/GLOBIO.org

Going the Distance

Elephants move great distances to find food and water. A herd can travel 32 km or more in one day. They use their trunks to break branches and knock down small trees so that they can more easily eat the leaves. Elephants also use their tusks and trunks to dig deep holes, or wells, in dry riverbeds to reach the water below. To drink, an elephant uses its trunk like a straw. It slurps as much as 10 l of water into its trunk and then squirts the water into its mouth.

Reshaping the Landscape

A landscape never looks quite the same after a herd of elephants has passed through it. Elephants have almost as much influence on shaping their environments as humans do. Elephants “open up” habitat when they eat large amounts of vegetation, which makes the area more inviting for a number of other animal species. The “wells” they dig also attract other animals to the area.
Elephants affect their habitat more than any other creature except humans. Over a few years elephants can change a forest to a grassy field, or dig a small hole that one day becomes a lake. Nature couldn’t easily recover from damage caused by the overcrowded elephants in this small.
Elephants affect their habitat more than any other creature except humans.  Over a few years elephants can change a forest to a grassy field, or dig a small hole that one day becomes a lake. Nature couldn’t easily recover from damage caused by the overcrowded elephants in this small park.
©G.Ellis/GLOBIO.org

How Low Can They Go?

Elephants communicate with each other using at least 25 calls, all of which have different meanings. Humans can hear some of these sounds, like the loud trumpeting elephants make with their trunks. But other calls are so low in frequency that humans can’t hear them. Elephants can hear an infrasound call quite easily—even if the elephant making the call is as far as 4 km away!
Elephants have very great memories and elaborate greetings when they haven’t seen a neighbor for many months or years. For several minutes, the two old friends will touch trunks, feel one another’s faces, and stick trunk tips in each other’s mouth.
Elephants have very great memories and elaborate greetings when they haven’t seen a neighbor for many months or years. For several minutes, the two old friends will touch trunks, feel one another’s faces, and stick trunk tips in each other’s mouth.
©G.Ellis/GLOBIO.org

Let’s Shake on It

Elephants also use body language to communicate. For example, when two elephants meet, they may grasp each other’s trunks. This behavior is a bit like a human handshake. Elephants use it as a way of saying “hello” to each other or to test each other’s strength.

Smarty-pants Elephants

Elephants are one of the most intelligent animals on Earth. They also have very good memories. Scientists believe that a herd’s matriarch remembers the location of water sources and feeding grounds and passes this information on to younger female elephants. When one of these young elephants becomes the herd’s new matriarch, she will pass on what she’s learned as well.

Vanishing Giants: Why Are Elephants Endangered?

Despite international treaties and bans on killing elephants, poachers still shoot them for their tusks. The tusks are made from ivory and can fetch hundreds of dollars in illegal trading. Giant tusks over 3m (10ft) long were once common, today they are rarely seen on live elephants.
Despite international treaties and bans on killing elephants, poachers still shoot them for their tusks.  The tusks are made from ivory and can fetch hundreds of dollars in illegal trading. Giant tusks over 3m (10ft) long were once common, today they are rarely seen on live elephants.
©G.Ellis/GLOBIO.org
In the early 1900s, there were more than 5 million elephants in Africa and Asia. Today, there are fewer than 500,000, as a result of hunting (legal and illegal) and habitat destruction. People are the biggest threat to the survival of elephants both in Africa and Asia. One of the main reasons people hunt African elephants is for their ivory tusks. People have been using ivory for thousands of years to make statues, jewelry, and decorations. Today, most countries have made hunting elephants illegal. But, there are people willing to buy ivory illegally and pay a high price for it. For this reason, there are still poachers who will illegally kill a grown elephant, so they can sell its ivory tusks.

Elephants and People

Today there are more working Asian elephant than wild ones in Asia. Loss of forest habitat and growing human populations across SE Asia and India have dramatically impacted these incredible animals.
Today there are more working Asian elephant than wild ones in Asia.  Loss of forest habitat and growing human populations across SE Asia and India have dramatically impacted these incredible animals.
©G.Ellis/GLOBIO.org
People have always been amazed at the great size and strength of elephants. Long ago, elephants were sometimes used on the battlefield. Soldiers riding atop them would charge at the enemy. The sight of a giant elephant in armor could terrify the enemy soldiers into running away.
In Asia, elephants are trained to work for people. They carry people and supplies through tropical forests and help with logging by moving giant logs from place to place. Asian elephants have even been used as taxis to carry people through slow traffic.
In India, Thailand, and other Asian countries, elephants are honored as symbols of good fortune. People sometimes decorate elephants and include them as part of traditional religious ceremonies.

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