Natural selection is a wonderful thing. The walking stick.

Walking stick

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The Phasmatodea are an order of insects whose members are variously known as stick insects, stick-bugs, walking sticks or bug sticks.

They are unusual in that the whole order is camouflaged. They are all mimics of their natural background. Some species are covered in mossy or lichenous outgrowths that supplement their disguise. Some species can change color as their surroundings shift. Many species have a rocking motion, where the body sways from side to side, like leaves or twigs swaying in the breeze. The nocturnal feeding habits of adults also helps them to hide from predators.

Mating involves long pairings. A record among insects, the Indian stick insect Necroscia sparaxes was seen coupled for 79 days at a time. It is not uncommon for this species to assume the mating posture for days or weeks on end, and among some species, pairing has been seen to last three to 136 hours in captivity. Explanations for this behaviour range from males guarding their mates against other males, to the view that the pairings are a defensive alliance against predators.