Sharon Braman, age 10, of Fountain Valley, California, for her question:
Does the platypus have any relatives?
The duckbill platypus has one living relative, though they do not look at all like cousins. Scientists class them in the same animal order because of certain features hidden in their bodies. They also class them as the most simple mammals. This is because they are most like the ancestors of the mammals that lived on earth way back during the days of the dinosaurs. The strange looking duckbill's cousin is the strange looking spiny anteater, also known as the echidna.
We all know that mammals are warm blooded, air breathing animals that wear fur. They are called mammals because their babies are fed on mother's milk. Two hundred years ago, scientists were sure that all mammals gave birth to live babies. Then the duckbill platy¬pus and the echidna were discovered in quiet hideaways of Australia and nearby islands. They are warm blooded, air breathing animals with fur coats and their babies feed on mother's milk. So they must be rated as mammals but these strangers are egg laying mammals.
The duckbill and the echidna are both about the size of a smallish, stubby legged dog. But they do not look like relatives and they live very different lives. Neverthe¬less, they are classed as cousins because they share certain important features that make them different from all the other living mammals.
Though warm blooded, their temperatures are somewhat lower than other mammals. Their simplified bones resemble the skeletons of lizards and the adults are toothless. Both have noses that look like duck bills and both lay round, soft shelled, reptile tape eggs. Their baby milk oozes from special pores and the helpless little infants lap it from mother's fur. The duckbill cousins have one more unusual feature. Their bodies have only one opening to get rid of both solid and liquid wastes and the same opening also lays the eggs.
This feature was cited when these strange mammals were classified in an order of their own. The platypus and the echidna share the Order Monotremata, which means the animals with one body opening. The platypus of Australia and Tasmania has a genus and species of his own. The echidna has a genus group of his.own, However, the echidna of New Guinea is somewhat larger thap his relatives in Australia anal Tasmania. Some scientists rate them as two different species.
The furry platypus digs burrows in muddy river banks and loves the water. He has webbed feet and a flat, beaver type tail. His menu includes crayfish and other small water creatures. The echidna enjoys life on the dry land and digs his burrows in sandy soil. He has no tail worth mentioning, no webs on his toes and the fur on his back is mixed with porcupine type quills. His favorite food is termites.
Scientists suspect that the strange monotremes are like the very first mammals that lived millions of years ago. In the days of the dinosaurs, these mammal ancestors lived in many lands. Only the platypus and the echidna survived unchanged to modern times. This was because the fierce mammals that came later never reached their lonely islands.