Mantids are top predators in a food chain of other insects and even vertebrates such as small mammals, birds, or reptiles. Using large, compound eyes that are widely spaced for binocular vision, they swivel their heads as far as 180 degrees to spot prey. Most mantids are ambush predators, sitting still and waiting for prey to come close. Their long front legs are armed with rows of sharp spines that they use to grab and impale the prey. A few mantids actively chase prey, running after them on long legs. Once captured, prey are eaten alive, sliced and chewed up piece by piece. Wiggling prey may be eaten head-first . When at rest, mantids fold their long legs beneath them in a prayer-like position, or sit cleaning their legs with their mouths. Sometimes mantids eat each other (cannibalism), such as females that occasionally devour males during mating or hatchlings that cannibalize each other.