Most of the world's snakes lay roundish eggs with soft shells. Pythons, king cobras and several other snakey mothers coil around their eggs and guard the nests. Pythons are non poisonous snakes, the cobras are poisonous. A few mothers of both types keep the eggs inside their bodies until the embryos become fully developed. They give birth to live babies, sometimes in sheaths that look like clear cellophane wrappers.
So far as we know, all the boas give birth to live babies. These non poisonous snakes are constrictors that crush their victims in their coils. Our venomous copperheads give birth to litters of three to ten live babies. Our poisonous rattlers also bear live young. But the venomous bushmaster of the American tropics lay eggs. A non poisonous anaconda 17 feet long may give birth to a litter of 32 live babies, each measuring about 27 inches. Some non poisonous snakes lay eggs and some hear live babies. The same holds true for the poisonous snakes.