Concept in Definition ABC

As a general guideline, most mammals grow and develop within the womb. When the young are born they are well formed and are already able to adapt to a normal life. However, marsupials are mammals that do not meet this characteristic.

The Kangaroo Example

A baby kangaroo lives for only five weeks in the mother's womb. At the time of birth, it is very small, it lacks hair and it cannot see.

As a consequence, it has to crawl from the birth hole to the maternal pouch where the nipple is located. In contact with the nipple, it grabs onto it and mother she begins to produce milk. For several weeks the baby hangs on the nipple and in this way begins to grow and develop. The bag where the baby is located, known as the marsupium or marsupial bag, works as an external matrix that serves as shelter and protection.

Once the calf has grown sufficiently, it is ready to jump out of the pouch for some periods of time. After ten months it is too big to fit in the mother's pouch and it eventually abandons it.

Physiologically, the female kangaroo is distinguished from other mammals by its apparatus player. It has two uteri, two independent vaginas, and an underdeveloped placenta. On the other hand, the penis of males is biffe at its end and is located behind the scrotum.

Most marsupials live in Oceania

These animals are native to Australia, Tasmania, and New Guinea. Its size is highly variable, as some species are very small, while others are as large as a human being. Among the small ones, the Tasmanian devil and the marsupial anthill stand out. The largest are the koala and the kangaroo.

The species Less well known is the rat kangaroo (Potorous gilbertii), an animal that was believed to be totally extinct but in the 90s living specimens were found.

As for koalas, they are found in danger of extinction and its greatest threat is chlamydia, a disease that leaves them blind and causes infertility.

The possum is native to the continent American. Most of the day it lives in the trees and its feeding it is very varied. It is a clumsy and slow animal, but it is difficult to catch as it knows how to camouflage itself and when it feels trapped it pretends to be dead.

Unlike other marsupials, it generates antipathies among humans, as it feeds on chickens and other animals of farm.

Photo: Fotolia - indomercy