Practically everyone has owned a teddy bear as a child, but not everyone
realizes that the animal it is modeled on is not a bear at all. Bears are
placental mammals where are the Koala, which is often called the Australian
teddy bear, is another marsupial mammal grouped with the phalanger family. It is
interesting that a number of the marsupials restricted to the Australian region
look and act like placental mammals found in other continents. The gliding
Phalanger is very much like the flying squirrel for example. Why is this?
About fifty million years ago
Australia became cut off from the other continents as the mammals evolved. This
allowed the marsupials to adapt themselves to live in every kind of habitat,
free from competition from the more advanced placental mammals. In every other
continent the Placental flourished and replaced the marsupials so shat apart
from Australia (and America where some opossums have somehow managed to
survive), marsupials are found nowhere else in the world. So, in separate
continents, representatives from two unrelated groups of mammals became adapted
to live in all the available habitats. Where particular conditions were the same
in either continent, the animals which evolved to suit them bear similarities in
shape and behavior. This phenomenon is called parallel or convergent evolution.
