They have no ears, but pick up sound vibrations from the ground. They smell with their tongue, which picks up minute particles floating in the air as it flickers in and out. The boa constrictor kills its victims by squeezing them until they suffocate. Boas grow up to 5.5m long, but some constrictors are even bigger. The anaconda of America is up to 11m long.
Rattlesnakes are venomous American snakes.
They get their name from the way they rattle their bony tails. Eggs Like all reptiles, young snakes come from eggs. In some snakes the egg develops inside the mother. But in most the eggs are laid, then hidden out of sight in hollow trees, under stones or in dung heaps. The mother usually abandons the eggs and lets them fend for themselves.