How Pit Vipers Use Camouflage

Ground-dwelling pit vipers -- such as rattlers and copperheads in the United States, fer de lance and bushmasters in Central and South America, and Gaboon adders in Africa -- often have earth tones and complex patterns, which help them blend into leaves, rocks and shadows. Copperheads effectively conceal themselves in piles of old leaves, while sidewinder rattlesnakes match sandy desert floors. Pit vipers that live in trees might be much brighter to match their environments. Green eyelash vipers often conceal themselves among palm leaves, while their bright yellow relatives lurk unnoticed within bunches of bananas, and the red morphs hide in bromeliads.

A primary reason for pit vipers’ camouflage is to conceal them from potential prey. Their pits enable them to sense warm-blooded animals -- birds, mice, rabbits, rats and even, for the massive Gaboon vipers, porcupines and antelopes -- nearby. Pit vipers also have keen eyesight, which helps them detect other food, such as frogs and lizards. The snakes remain concealed until a possible meal wanders within striking range, when they attack and inject venom through their fangs.

Some pit vipers use their camouflage to lure prey. For example, juvenile bushmasters, copperheads and cottonmouths have yellow tips on their tails, which they wriggle in a way that simulates the movement of caterpillars or worms. Would-be predators, such as larger caterpillars and frogs, lunge toward this bait, and the snakes attack. By the time these vipers reach adulthood, their tails darken to match the rest of their bodies.

Pit vipers’ camouflage also can provide protection -- which sometimes makes them more dangerous to people. The 6 1/2-foot fer de lance often conceals itself in plantations and on paths traveled by both prey animals and human workers, leading to numerous bites. On the other hand, scientists don’t know of any non-human predators that attack Gaboon adders, possibly because of how effectively these sub-Saharan pit vipers hide themselves on rainforest floors. While they’re capable of navigating on the ground, eyelash vipers rarely do, because they’re less camouflaged and therefore more vulnerable on the forest floor.