Kathy Gregory, age 10, of Franklin, North Carolina, for her question:

Do all poisonous snakes lay eggs?

We share our world with almost 3,000 different snakes, and of these, less than 300 varieties have poisonous fangs. Most snakes lay eggs, and the mothers leave their offspring to hatch in the warm ground. But some mother snakes keep the eggs in their their bodies until the youngsters are fully developed. These are the live bearing snakes that give birth to young baby snakes. Some of the nonpoisonous snakes bear live babies. So do some of the poisonous types, but not all of them.

The deadly cobras of Asia lay their eggs in leafy nests and guard them until they hatch.

The black mamba is a dreaded poisonous snake of Africa. The mother lays eggs. Our gaily painted, poisonous coral snake also lays eggs, usually only three or four at a time.

The poisonous bushmaster lays a larger brood of eggs. Our venomous copperheads and cotton mouths both bear litters of live babies. Most of our poisonous snakes are rattlers and all of these dangerous serpents bear their young alive.