Category Zoology

                    The largest living land animal is the African elephant, which reaches a weight of 7,500 kg and stands 3-4 m high at the shoulders when fully grown.

                    However, the African elephant is dwarfed by some extinct plant-eating dinosaurs, which may have weighed at least 80 tonnes, and reached a length of 30 m. It was thought that the weight of these huge creatures had to be supported by water. It is now known that they inhabited regions similar to those of elephants.

                               Mammals, like other animals, sometimes develop a body shape or lifestyle that is very similar to that of an unrelated animal living in exactly the same environment.

                               Dolphins, for example, have a very similar body shape to sharks and to the extinct marine reptile ichthyosaurus, because they inhabit the same environment and have a very similar way of life. In the same way, kangaroos have adapted to a similar lifestyle to antelopes and sheep, grazing in open grasslands. This process is called parallel evolution, and it demonstrates how animals develop in the same way, in order to fit in with the available living space and food supply.

Picture credit: google

                  Bats are the only mammals that are capable of true flight. Several other mammals are capable of gliding for considerable distances.

                  Bats are efficient flyers, although their wings have developed very differently from those of birds. A bat’s wing is like an outstretched hand with very long fingers, connected by thin skin. Other mammals, such as squirrels and marsupials, are able to glide by means of sheets of skin stretched between their front and back legs. They use these sheets to travel from tree to tree. These animals are not closely related and yet they have developed the ability to fly quite separately, so this is an example of parallel evolution.

Picture credit: google

                        Shrews are the smallest kind of mammal. Some weigh only 2.5 g. A shrew looks like a mouse with a long snout, but it is not closely related to rodents. Shrews feed on insects and other animals, and need to eat almost continuously in order to survive.

Picture credit: google

                        Most mammals nourish their developing babies in the womb through an organ called the placenta. Marsupials do not have this organ.

                       In marsupials, the baby is born at a very early stage of its development, and is usually only a few millimetres long. The baby makes its way slowly up the mother’s stomach and crawls into a protective pouch. The baby attaches itself to a teat through which it receives milk while it develops. As the baby grows larger it is able to leave the pouch, returning to feed. Marsupials are said to be more primitive than most other mammals. However, they are highly successful in Australia where they have been isolated from invasion by other animals and have survived for millions of years.

                  True mammals all give birth to live young, which are smaller versions of the adult animal.

                  An unusual group of Australian mammals, called monotremes, lay eggs. The echidnas, or spiny anteaters, are monotremes. The other monotreme is the duck-billed platypus. The appearance of this animal is so strange that when it was first described scientists assumed that the animal was a clumsy fake! The duck-billed platypus has a leathery bill shaped like a duck’s beak; a body similar to an otter and a tail very much like a beaver’s. To make things even stranger, it has poisonous spurs on its legs too!