Minggu, 01 Mei 2011

Report Text_Koalas


Koalas

Unbearably Adorable

In a contest for cuteness, koalas would win, paws down. Their cuddly looks make these animals the favorites of many people. Koalas look like teddy bears and are sometimes even called “teddies,” but koalas aren’t bears. Like kangaroos and opossums, koalas are marsupials, that is, mammals that carry their young in a pouch on their bodies. Koalas live only in eastern Australia. Even though these animals are known for their looks, you’ll soon see there’s a lot more to koalas than just a pretty face.
They may look like bears but koalas are Australian tree-dwelling cousins of the kangaroo. Like “roos” they are marsupials that raise their babies in a belly pouch.
They may look like bears but koalas are Australian tree-dwelling cousins of the kangaroo.  Like “roos” they are marsupials that raise their babies in a belly pouch.
©G.Ellis/GLOBIO.org

Body Basics

The koalas that live in southeastern Australia are larger than those that live in northeastern Australia. They also have thicker, darker fur. The southeastern koalas range from 9 kg to 14 kg, while the northeastern ones are about 6 kg to 7 kg.

Koala Cousins

A koala’s closest living relative is the wombat, another marsupial that lives in Australia. Koalas are believed to have evolved from large koala-like animals that lived in Australia millions of years ago. The oldest koala-like fossils that have been found are about 25 million years old.

Trees, Sweet Trees

Koalas can be found in a variety of habitat but they require forests rich in eucalypt to survive. Before human development, most of Australia’s eastern coast looked like this in southern New South Wales.
Koalas can be found in a variety of habitat but they require forests rich in eucalypt to survive. Before human development, most of Australia’s eastern coast looked like this in southern New South Wales.
©G.Ellis/GLOBIO.org
One of the things that make koalas so special is that they’re so highlyadapted to their habitat. The only place they live is in sub-tropical andtemperate forests. But not just anyforests—they live only in eucalyptus tree forests. That’s because just about the only thing koalas will eat is eucalyptus leaves. But not justany eucalyptus leaves either! Of the 600 species of eucalyptus trees in Australia, koalas eat the leaves of only about 50 of them. And even out of these, they will have just a few favorites that they eat most of the time. Koalas in different regions eat different kinds of eucalyptus leaves.

Out on a Limb

Imagine having your favorite food at your fingertips anytime you wanted it. That’s what life is like for koalas. They live high in the tops of the eucalyptus trees that they feed on. It sure is convenient. It also keeps them safe from predators, such as wild dogs or even pet dogs. Koalas are well adapted for treetop life. They have a great sense of balance. Plus, they have built-in “climbing tools” like sharp claws and rough paws. Koalas are able to jump from branch to branch or tree to tree. But they’ll also climb backward down to the ground in order to move to a different tree.

Chow Time

Koalas feed exclusively on eucalypt leaves. When they are awake, they spend most of their time munching up to a thousand chewy leaves a day!
Koalas feed exclusively on eucalypt leaves. When they are awake, they spend most of their time munching up to a thousand chewy leaves a day!
©G.Ellis/GLOBIO.org
For koalas, life is all about leaves. Adult koalas eat about 1,000 eucalyptus leaves every day. They eat so many that they actually smell like eucalyptus! But even in the right tree with the right leaves, koalas are still fussy eaters. They prefer to eat just the tips of the leaves, because they are the juiciest, softest parts of the leaves. Eucalyptus leaves are poisonous to most animals. But koalas havebacteria in their stomachs that break down the poisons so that the koalas can eat the leaves. Koalas even get their water from the leaves, so they hardly ever need to drink. The name koala may come from a word that means “never drink.”

Beauty Sleep

Koalas can spend up to 18 hours sleeping each day. They stay curled up like a ball high in the eucalypt tree branches. A koala will stay snoozing even if stormy winds toss it around. In southern Australia, where it can get cold, people have spotted snow-covered koalas sound asleep!
Koalas can spend up to 18 hours sleeping each day. They stay curled up like a ball high in the eucalypt tree branches. A koala will stay snoozing even if stormy winds toss it around. In southern Australia, where it can get cold, people have spotted snow-covered koalas sound asleep!
©G.Ellis/GLOBIO.org
Eucalyptus leaves are not very nutritious. Koalas save their energy by sleeping...and sleeping…and sleeping! It’s not unusual for koalas to snooze for up to 20 hours a day! They are mostly nocturnal, which means they are usually more active at night. That’s why if you’ve ever seen a koala at a zoo, it was probably curled up in the fork of a tree, dozing away.

The Loud Crowd

For most of the year, koalas keep to themselves and lead quiet lives. Mating season is a more active—and noisy—time in a eucalyptus forest. Male koalas call for mates and claim their territories with loud bellows that sound like giant snores followed by burping sounds. Males will also mark their territories using a scent gland on their chests. When they rub against tree trunks, the gland oozes a dark, sticky substance. This “tree mail” is a message to other koalas to stay away. If they don’t, there may be a fight. Koalas look cuddly, but with their sharp claws and teeth they can be tough when they want to.

Baby Joey

A newborn koala is smaller than the end of your finger. The pink, hairless and defenseless joey stays inside the soft pouch for the first six to seven months. Almost six months pass before it pokes its head out.
A newborn koala is smaller than the end of your finger. The pink, hairless and defenseless joey stays inside the soft pouch for the first six to seven months. Almost six months pass before it pokes its head out.
© D.Parer & E.Parer-Cook/Minden Pictures
A baby koala—called a joey—is only about the size of a jelly bean when it is born. It’s bright pink and has no hair. It can’t see or hear, but it’s a great little climber. Using its strong arms and claws, the newborn joey climbs through its mother’s fur until it gets to her pouch. Inside the warm, furry pouch it sniffs out one of two nipples and attaches to it. The nipple swells inside the joey’s mouth to prevent the joey from losing its hold. The joey stays inside the soft pouch for the next six to seven months. It drinks its mother’s milk and grows larger. Its eyes and ears develop, too, and its fur comes in. When the joey is about 22 weeks old, its eyes open, and soon it begins peeking out of the pouch!

From Pouch to Piggyback

Now the joey adds something else to its menu besides milk. It starts eating a food called “pap,” which its mother produces in her body. Pap is actually a soft, runny form of koala droppings. It’s a very important food for the koala. In the pap, the mother passes on bacteria that the joey will need to be able to digest eucalyptus leaves. Eventually, the joey spends more time out of the pouch. It begins riding on its mother’s back. It begins eating leaves, but it still drinks milk from its mother. After about a year, it’s able to live on its own.
Koala joeys stay very close to mom for protection and to learn what to eat. Joeys ride on mom’s back, or joey style, when they start to get too big for the pouch.
Koala joeys stay very close to mom for protection and to learn what to eat. Joeys ride on mom’s back, or joey style, when they start to get too big for the pouch.
©G.Ellis/GLOBIO.org

Some Bad News

Unfortunately, life isn’t always easy for koalas. They have few natural predators, although dingoes, owls, eagles, and pythons sometimes prey on young koalas. Koalas’ worst enemies by far have been humans. A long time ago, millions of koalas lived in Australia. Then people started killing them for their soft fur. Between 1919 and 1924, 8 million koalas were killed. Now it is illegal to kill koalas, but they still have their troubles.
The biggest problem koalas have is that they are losing their habitat. The loss of habitat is due to logging, land development, and fires. These have led to changes in the environment that have harmed and killed many eucalyptus trees. Koalas need to live in eucalyptus trees. When there aren’t enough of these trees, the koalas have to move across the ground to find new ones. This puts them in danger of being hit by cars or attacked by dogs. More than 4,000 koalas are accidentally killed this way each year. Many koalas also suffer from disease.

The Good News

Koala crossing signs are a key to protecting koalas that now must crawl down from trees and cross open ground to reach new forests. Loss of trees to connect large patches of habitat, or corridors, is a major problem to their long-term survival.
Koala crossing signs are a key to protecting koalas that now must crawl down from trees and cross open ground to reach new forests. Loss of trees to connect large patches of habitat, or corridors, is a major problem to their long-term survival.
©Peter Firminger
There are probably about 100,000 koalas left in Australia today. Koalas are not an endangered species—at least not yet. Many people are working to try and make sure they never are. Scientists are studying koalas to learn about what they need to stay healthy. Breedingprograms in zoos and other protected places are increasing the number of koalas. People are planting thousands of new eucalyptus trees where the koalas need them. They are also trying to make laws to protect the eucalyptus trees that remain. To keep koalas safer as they cross roads, “koala crossing” signs have been put up. In some places, nighttime speed limits have been lowered. Just recently, scientists developed a vaccine that could keep koalas from getting a disease that many of them have.

Crazy About Koalas

The other good news is that people love koalas. Even thousands of years ago, koalas were part of ancient Australian stories. Today, their furry faces appear everywhere from posters and T-shirts to coins and stamps. One airline even featured a live koala in its TV commercials. Every year, people flock to zoos to see koalas. People’s fondness for koalas makes them want to help protect them. And that may guarantee these furry fuzzballs a brighter future.

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