Kate Morris, age 12, of Wichita, Kansas, for her question:

Do only birds have feathers?

If an animal wears feathers of any sort, you can be sure he is a bird and no other kind of animal. Yes indeed, the birds are the only earthlings that have feathers. True, some of the moths wear fuzz that seems somewhat like the feathery down worn by baby chicks. But this fuzz is not related to true feathers. There are no feathers in the world of insects, in the world of fishes or in the world of mammals.

Nature provides her wild children with the clothing that suits them best. Fishes have waterproof scales, mammals have warm fur. The birds, and only the birds, have lightweight feathers that are both warm and usually waterproof.