After that they swallow them whole. Vipers are not as large as anacondas, they grow up to only 6 feet long. But they are just as deadly. Vipers use their sharp fangs to kill their prey, these sharp fangs inject poison. Between their eyes and their nostrils many vipers have special pits, these pits help snakes sense their prey in dark places.
Vipers attack little animals such as lizards, but some can kill people too.