Why Do Caterpillars Twitch? {Are They Angry?}

Have you ever seen caterpillars twitch or dance? Why do caterpillars twitch?

Are they annoyed, angry or happy? Why do they like to shake their heads?

In this article, we’ll find out why caterpillars twitch.

Why Do Caterpillars Twitch?

Caterpillars tend to twitch when they are hearing loud sounds or trying to ward off attacks from potential parasites or predators. If a parasite was laying eggs in the area where caterpillars hatch from, the disturbance in their territory would cause a group of caterpillars to begin twitching.

These caterpillars are clearly disturbed. Twitching is a form of protection. Twitching caterpillars can confuse birds that may fly off without being able to catch one in their mouth.

Some birds drop caterpillars from their mouths when they are twitching.

Why Do Caterpillars Shake Their Heads?

Caterpillars may shake their heads when they hear loud sounds. They hate the threat of any potential predators attacking them. They will twitch their bodies and heads.

Apparently the sound of a scream can create a frequency that triggers caterpillars to begin twitching. If parasite flies are attempting to lay eggs near their location on a plant, they will also shake their heads or twitch.

Why Do Caterpillars Dance?

Caterpillars look like they are dancing when they are trying to ward off any predators. They are busy trying to eat their way through a leaf and all of a sudden the parasitic fly or a larger predator swoops down to attack.

The caterpillars can rear up their back legs into the air and make themselves look more threatening to predators.

It may look like they are dancing, but what they are trying to do is defend themselves. A bird can try to snap at a caterpillar who is twitching and miss.

Other birds may catch a caterpillar in their mouth and let it go when it starts to twitch out of control.

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Why Are Caterpillars Twitchy?

Caterpillars can sometimes twitch when they get too close to each other. When a caterpillar is busy munching on plant matter, they do not like to be disturbed.

Another caterpillar for example, who encroaches on this territory may cause the initial caterpillar to begin twitching.

Some caterpillars scare easily and begin twitching as a form of defense. Other caterpillars twitch when they are agitated.

Caterpillars can twitch when they feel vibrations that are loud. There are still a lot of studies that need to be conducted to find out more reasons why caterpillars twitch.

We have compiled the following reasons why they twitch:

  • Defense mechanism
  • Ward off predators
  • Demand space from other caterpillars
  • Wishing to be left alone
  • Agitation from parasitic flies
  • Response to loud sounds
  • Avoid being eaten


Next time you see a caterpillar twitching, know that they are not happy and they are not dancing. They are most likely trying to stay alive or show their agitation at a current situation that is interrupting them from their feast.

When a bird is trying to attack a single caterpillar or a group, the twitching that you may notice from caterpillars may help to confuse the predator.

It’s easier to snap up a worm that is moving slowly rather than a twitching caterpillar that is doing everything it can to save itself from becoming the next meal for a bird or another predator.

You can try to make a caterpillar twitch by putting a rock next to it or screaming really loudly. Let us know in the contact us section of this website with any story that you have relating to caterpillars that twitch.


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