Kathy Skidmore, age 13, of Stratford Conn., for her question:

What is the difference between hair and fur?

Fur is no more than very soft hair. Even wool is a special kind of hair. And, strange to say, the quills of a porcupine are also hair. We find hair, in some form or other, growing on the skins of almost all mammals. Even the smooth skinned whale, who is a mammal, has a few bristles which can pass as hair.

Hair can be tough and bristly, as it is on a pig. It can be harsh and wiry, as it is in the horse's mane. When it is very soft and silky, we call it fur. A rabbit's hair is soft enough to be called fur, as is the undercoat of the beaver.

The most famous fur‑bearing animals belong to the stoat family. These best dressed animals are the mink, the otter, the marten and the ermine. Their soft, silken coats are really made of fine hairs. And, when hair grows very fine and thick, with many more threads to the square inch we call it fur.