As its name suggests, the stick insect resembles the twigs among which it lives, providing it with one of the most efficient natural camouflages on Earth. It and the equally inconspicuous leaf insect comprise the Phasmida order, of which there are approximately 3,000 species.
Stick insect species, often called walking sticks, range in size from the tiny, half-inch-long (11.6-millimeter-long) Timema cristinae of North America, to the formidable 13-inch-long Phobaeticus kirbyi of Borneo. This giant measures over 21 inches with its legs outstretched, making it one of the world’s longest insects. Females are normally larger than males.
Phasmids generally mimic their surroundings in color, normally green or brown, although some species are brilliantly colored and others conspicuously striped. Many stick insects have wings, some spectacularly beautiful, while others resemble little more than a stump. A number of species have spines and tubercles on their bodies.
Found predominantly in the tropics and subtropics—although several species live in temperate regions—stick insects thrive in forests and grasslands, where they feed on leaves. Mainly nocturnal creatures, they spend much of their day motionless, hidden under plants.
Many stick insects feign death to thwart predators, and some will shed the occasional limb to escape an enemy’s grasp. Others swipe at predators with their spine-covered legs, while one North American species, Anisomorpha buprestoides, emits a putrid-smelling fluid.