An estimated 50-125,000 fatalities a year.

Can be found in Africa, Asia and North America.

Snakes are very fast and any part of the human body is a good place for a bite, seeing as the venom can flow into the bloodstream within minutes; although those near major veins and arteries will travel faster. Snakes use their venom to paralyse their prey. A fully grown king cobra can rear up so it looks a man in the eye; others can spit venom into the eye. Nasty.

Unsurprisingly, most people come a cropper when they try to harass a snake or draw close to it. Snakes will usually only attack if they're feeling threatened so the short answer is: stay away! Wear stout boots if hiking and check either side of paths. Don't mess about looking under rocks or fallen vegetation as you'll get more than you bargained for. If you come across a snake, back away very slowly, as it can strike to half its length and sudden movements are likely to alarm it.

A venomous snake is a snake that uses modified saliva, venom, delivered through fangs in its mouth, to immobilize or kill its prey. Venomous snakes include several families of snakes and do not constitute a formal classification group used in taxonomy. The term poisonous snake is false - poison is inhaled or ingested whereas venom is injected. (In contrast, most non-venomous species are constrictors which suffocate their prey.) Snake venom can contain many different active agents, and can potentially be a mix of neurotoxins, hemotoxins, cytotoxins, bungarotoxins and many other toxins that affect the body in different ways. Snake venom is never a single type of toxin. Neurotoxins attack the nervous system, while hemotoxins attack the circulatory system.

Venomous snakes that use hemotoxins,neurotoxins usually have their fangs to secrete the venom in the front of their mouths, making it easier for them to inject the venom into their victims. Snakes that use neurotoxins, such as the mildly venomous mangrove snake, have their fangs located in the back of their mouths, with the fangs curled backwards. This makes it both difficult for the snake to use its venom and for scientists to milk them.

All snakes are carnivorous, eating small animals including lizards and other snakes, rodents and other small mammals, birds, eggs or insects. Some snakes have a venomous bite, which they use to kill their prey before eating it. Other snakes kill their prey by constriction. Still others swallow their prey whole and alive. Most snakes are very easy to feed in captivity, apart from a minority of species.

Constrictors use a variety of ambush techniques, according to Cornell University herpetology professor Harry Greene. Diamond Pythons perch in trees waiting to seize arboreal animals. Puerto Rican Boas wait around the openings of caves to capture bats, while Green Tree Pythons lure their prey with their tails. Corn Snakes first bite their prey to get a good grip, then quickly coil themselves around and constrict. But the constrictor most feared by humans is probably the Anacondas of South America. The Green Anaconda, which may reach 10 metres in length is the heaviest snake on the planet. Hiding in the watery lagoons it prefers, it will lie in wait for birds and mammals wading or drinking. Though it has poor eyesight, it has infrared sensors that can detect less than one degree difference in temperature. It strikes at six metres per second.