Dean Dunsworth, age 9, of Gallup, N.M., for his question:

IS THE PLATYPUS A MAMMAL OR A REPTILE?

Our friend the platypus, who is also called a duckbill, is a water living mammal. The lady in the family is the only mammal, other than the anteater, who both lays eggs and nurses her young. She lays rubbery eggs that very much .resemble those of a reptile. The eggs are deposited in a dug out spot along the stream bank and they hatch out in about 75 days.

Instead of a snout, the platypus has a skin covered flat jaw that looks just like the bill of a duck. The man of the family has poison secreting glands in his hind claws which come in handy when he's fighting. He's about two feet long when he reaches adulthood and has thick, coarse fur. His tail is flat.