One of the most infamous of the world’s venomous snakes, this species is the leading snakebite species in its habitat. It is found from southern Mexico down to Northern South America. Like rattlesnakes, cottonmouths, and copperheads, it is a pit viper, equipped with heat sensing organs in a cavity between their eyes and nostrils. Females grow much larger than males, weighing more than ten pounds, and have bigger heads and longer fangs. The haemotoxic venom causes severe tissue damage, and many fatalities have been recorded.