Koala, tree-dwelling marsupial with a specialized diet consisting almost exclusively of the leaves of eucalyptus trees. Koalas are native to Australia, where they are sometimes called koala bears or native bears, although koalas are not related to bears. Bears are placental mammals—their young develop fully inside the mother’s body, nourished by a spongy organ called the placenta. As marsupial mammals, koala young are born while still in an undeveloped state. Newborn koalas complete their development inside a pouch on the mother’s abdomen.
Today koalas survive in the remaining small patches of eucalyptus forests throughout eastern Australia, from the tropical northeast to the cooler southeast. These patches of forest are widely separated from each other, preventing koalas from moving from one patch to another to find new breeding partners or additional eucalyptus trees.
Koalas resemble a miniature bear, with a large head above a stocky body, a tiny tail, and long muscular limbs. They have a round face with forward-facing eyes; a blunt, prominent nose; and two round ears on top of the head. Koalas range in size from 69 to 79 cm (27 to 31 in) in length, and from 5 to 12 kg (11 to 26 lb) in weight. Males are generally larger than females, and koalas in the south tend to be larger than their counterparts in the north.
The eyes of koalas face forward on the head, enabling the animal to focus both eyes on a single object. This ability, known as binocular vision, allows koalas to accurately judge distances, an important skill for an animal that leaps between tree branches. Koalas appear to have a good sense of smell—they sniff leaves before selecting one to eat, suggesting that they can smell a difference among individual leaves. They also sniff the gland secretions left by males at the base of trees and on branches.
Koalas eat about 200 to 500 g (7 to 18 oz) of eucalyptus leaves per day. Eucalyptus leaves are low in nutrition, however, because they contain little protein and largely consist of fiber and other indigestible compounds. The koala has evolved unique adaptations to exist on this diet, and these adaptations influence many aspects of the animal’s digestive process, from the shape of teeth to the speed of digestion.
The teeth of koalas include four incisors at the front of the mouth, two in the upper jaw and two in the lower jaw. Cheek teeth, consisting of one premolar and four molars, are found in both the upper and lower jaws. A gap, called the diastema, separates the incisors and cheek teeth. Koalas use the incisors to grasp a single leaf and pull it into the mouth through the diastema. The animals then bite the leaf with their premolar, separating the leaf from its branch.
Today koalas survive in the remaining small patches of eucalyptus forests throughout eastern Australia, from the tropical northeast to the cooler southeast. These patches of forest are widely separated from each other, preventing koalas from moving from one patch to another to find new breeding partners or additional eucalyptus trees.
Koalas resemble a miniature bear, with a large head above a stocky body, a tiny tail, and long muscular limbs. They have a round face with forward-facing eyes; a blunt, prominent nose; and two round ears on top of the head. Koalas range in size from 69 to 79 cm (27 to 31 in) in length, and from 5 to 12 kg (11 to 26 lb) in weight. Males are generally larger than females, and koalas in the south tend to be larger than their counterparts in the north.
The eyes of koalas face forward on the head, enabling the animal to focus both eyes on a single object. This ability, known as binocular vision, allows koalas to accurately judge distances, an important skill for an animal that leaps between tree branches. Koalas appear to have a good sense of smell—they sniff leaves before selecting one to eat, suggesting that they can smell a difference among individual leaves. They also sniff the gland secretions left by males at the base of trees and on branches.
Koalas eat about 200 to 500 g (7 to 18 oz) of eucalyptus leaves per day. Eucalyptus leaves are low in nutrition, however, because they contain little protein and largely consist of fiber and other indigestible compounds. The koala has evolved unique adaptations to exist on this diet, and these adaptations influence many aspects of the animal’s digestive process, from the shape of teeth to the speed of digestion.
The teeth of koalas include four incisors at the front of the mouth, two in the upper jaw and two in the lower jaw. Cheek teeth, consisting of one premolar and four molars, are found in both the upper and lower jaws. A gap, called the diastema, separates the incisors and cheek teeth. Koalas use the incisors to grasp a single leaf and pull it into the mouth through the diastema. The animals then bite the leaf with their premolar, separating the leaf from its branch.
(sources:Microsoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.)
1 comment:
hoi...
i like your clock...
lae, i think you must give me koala's picture.
may be another person don't know what koalas is like,,,
hehehe
-amallya-
-2a1-
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