Do Praying Mantises Bite? Are Mantises Dangerous to People?

Can a praying mantis hurt you?

A mantis has two weapons: its jaws (mandibles) and its front legs. The jaws are strong enough to chew through the hard bodies of grasshoppers and beetles, but they are tiny compared with a human finger. Most small and medium mantises cannot even break the skin.

The forelegs are the part people usually feel. Each raptorial (grasping) foreleg has rows of sharp spines on the thigh and shin, and the leg closes like a pocketknife to hold prey. When a mantis grabs a fingertip, the spines prick and the grip can feel surprisingly firm. Many “mantis bites” are really this grabbing action.

Size makes a difference. The praying mantis of Europe is about 5–8 cm (2–3.1 in) long, while the Chinese mantis, introduced to North America, can reach about 11 cm (4.3 in). A big Chinese mantis can give a noticeable nip that may occasionally draw a tiny drop of blood. Even then, the effect is no worse than a scratch from a rose thorn.

Why would a mantis bite?

Mantises do not hunt people and do not bite out of aggression. A bite almost always has one of two causes.

The first is defense. A mantis that is picked up roughly, pinned down or squeezed will try to escape, and slashing with the forelegs and nipping with the jaws are its only options. The second is mistaken identity. Mantises strike at small things that move, so a hungry mantis may grab at a wiggling fingertip as if it were an insect, then let go once it finds it cannot hold or eat it.

Before biting, a disturbed mantis usually warns you. It rears up, spreads its wings, raises its forelegs and sways, a bluff called a deimatic (startle) display. The European mantis also flashes two black eyespots on the inside of its front legs. Some mantis species add a hissing sound made by pushing air out of breathing holes in the abdomen.

Are praying mantises venomous or poisonous?

Praying mantises are neither venomous nor poisonous. Venomous animals inject toxins through fangs, stingers or spines, and mantises have no such equipment. They subdue prey only by holding it tight and starting to eat, as described in what praying mantises eat.

Poisonous animals carry toxins in their bodies that harm whatever eats or touches them, like many brightly colored beetles and frogs. Mantises do not. They rely on camouflage and their bluffing display, which is why so many birds, lizards and frogs eat them. If you want the difference between the two terms explained, see venomous vs poisonous.

Why do praying mantises seem to stare at you?

Few insects seem as alert as a mantis. When you move near one, it often turns its head and appears to look you in the eye. In a sense, it really is watching you.

A mantis has a very flexible neck, and some species can turn their heads almost 180 degrees. Each large compound eye has a forward-facing zone called the fovea that gives the sharpest view. When the edge of the eye detects movement, the mantis swivels its head to bring the moving object into the fovea, then tracks it. A person walking past is simply a big moving object worth checking.

The dark dot that appears to follow you is not a pupil. It is a pseudopupil, the small patch of lenses that point straight at you and absorb the light, while the lenses around them reflect it. Whichever way you move, a different patch faces you, so the “pupil” seems to follow you.

Mantises also have true 3D vision. In 2016, scientists at Newcastle University fitted mantises with tiny 3D glasses and showed that they judged depth from the slightly different views of their two eyes, which is rare among insects.

Do mantises attack people?

No. People meet mantises mostly by accident: a male flying to a lighted window at night, a mantis riding on a garden hose, or a female sitting on a fence while looking for a place to lay eggs. A mantis that lands on you is usually just looking for a perch.

Mantises are most noticeable in late summer and autumn, when they are fully grown and the males fly in search of females. This is also when people most often pick them up, and therefore when most minor bites happen. Watching a mantis without grabbing it is the easiest way to avoid any pinch and does not stress the insect.

Myths about mantis bites

• Myth: Mantis bites are poisonous. No mantis has venom, and a bite cannot poison you.
• Myth: Mantises are aggressive toward people. They bite only when handled or when they mistake a finger for prey.
• Myth: It is illegal to kill a praying mantis. This is a long-running urban legend in the United States; no federal law protects mantises.
• Fact: Mantises are far more dangerous to each other. Mantises regularly eat other mantises, and females sometimes eat males during mating, as explained in why female mantises eat males.

In short, a praying mantis is a fierce hunter for its size but a harmless neighbor for people. The worst most of us will ever feel is a brief prick from a spiny foreleg.