Ron Shilling, age 9, of Shreveport, Louisiana, for his question:

Why do snakes have forked tongues?

A tongue tipped with two little prongs is very strange to us. Some people think it's scary, just because they don't know why a snake darts his forked tongue in and out of his mouth. In olden days they thought it was a stinger. Nowadays we know that it is a sort of feeler that tells the snake about the different things around him. There is no need for us to fear his forked tongue, but sensible folk do not trust his teeth    because he may bite a finger by mistake.

A snake likes to know what's for dinner, just as you do. Your nose tells you what's cooking in the kitchen, and often gives you a hint about how it will taste. A snake has a nose to sniff likely snacks    and that forked tongue also sniffs. He darts it out to capture invisible fragments of this or that in the air. He darts it back into his mouth to smell these tiny specks. The tip of his tongue touches two tiny dents in the roof of his mouth. They have sensitive nerves that know what smells there are in each sample of air. Most of the time, his clever tongue is busy sniffing for a suitable snack.