Venom controls much larger prey. Click on the image for RealVideo of a feast. And what an apparatus it is. According to Cornell University herpetology professor Harry Greene, the venomous snake's mouth acts remarkably like a hypodermic syringe. The oral glands hold the venom like a needle barrel, and when the snake bites, jaw muscles push the toxin like a plunger into the grooves of the fangs, which deliver the poison like a needle into the unlucky recipient.
Rattlesnakes are more likely to be tissue destroyers while cobras tend to inject neurotoxins.
To see video and learn more about how a snake swallows its prey, click above. The site of the bite dissolves - it becomes a big crater. Hemotoxins usually cause internal bleeding in human victims, with death resulting from shock. While we usually try to quantify venom potency by injecting it into mice and then calculating on average how much will kill, many other factors affect whether a snake bite will prove fatal. Some snakes that look very impressive on paper are known to be clinically much less.