There are three main types of toxic secretion in snakes designed to stop prey in its tracks. Cytotoxins are rich in enzymes and kick-start digestion of soft tissue before the prey has actually died. Neurotoxins block chemical signals in the victim’s central nervous system.
These venoms can paralyse muscles and interrupt respiration. Haemotoxins affect the blood. Some stop blood from clotting, which can lead to massive internal bleeding. Other haemotoxins kill by thickening blood to the point where it can’t circulate.