How Many Legs Do Caterpillars Have? 6 Interesting Facts About Caterpillar Limbs

Caterpillars are most often depicted with as many legs as a millipede, but is that actually the case? As it turns out, the answer is a little more complicated than that. Caterpillars and their counterparts, butterflies and moths, have quite an interesting story when it comes to counting their legs! Let’s learn a bit more about and discover: How many legs do caterpillars have?

How Many Legs do Caterpillars Have?

Almost all caterpillars have two types of legs: true legs and prolegs. True legs are segmented legs with claws or spikes at the tips. They are located on the thorax, the section of the body behind the head, and always come in three pairs, meaning caterpillars always have six legs. To be as accurate as possible, it is best to say that caterpillars have six true legs, especially since they are insects and all insects have six legs.

Prolegs are unsegmented, fleshy appendages with hooks or suckers at the ends. They are located on the abdomen, the body section behind the thorax, and vary between two and five pairs depending on the species. To many people, these nubby little appendages look like legs and can be quite confusing!

The true legs are what gets converted into adult legs after metamorphosis. The prolegs disappear during this process, which involves digesting most of their tissues inside a cocoon or chrysalis and reorganizing them into new structures such as wings, antennae, eyes and proboscises.

6 Interesting Facts About Caterpillars and Their Limbs

1. They Have Two Types of Legs

Sure, we already covered it, but it’s important to know! True legs are like normal insect legs. They have different parts and sharp ends. They are always six in total and near the head. Prolegs are like soft tubes. They have sticky ends. They can be four to ten in total and on the back part of the body.

2. Caterpillars Don’t Walk, They Undulate!

A caterpillar doesn’t walk like other animals. It moves its legs and body in a wave-like motion known as “undulation” or “undulating.” Essentially, looks like the caterpillar is making curves or loops with its body. It can also stretch or bend its body to reach different places.

3. Caterpillars Can Climb Smooth Surfaces With Their Prolegs

Caterpillars can climb smooth surfaces with their prolegs. Prolegs have small hooks or suckers at the end and help the caterpillar stick to surfaces like velcro. Some caterpillars also make a liquid silk that helps them glide like slugs. Using these strategies and anatomical advantages, caterpillars make for some pretty great escape artists for anyone trying to keep and then release them as butterflies.

4. Caterpillar Prolegs Get Turned Into Organs

It may sound weird at first, but it’s actually part of the metamorphosis process! When caterpillars metamorphose into butterflies or moths, they break down their bodies and rebuild them with new structures. One of the things that they lose is their prolegs, which is why you don’t see butterflies or moths with the prolegs, only the true legs!

5. Some Caterpillars Use Their True Legs as Weapons

Some caterpillars have sharp spikes or claws on their true legs. They use them to catch and kill other insects for food and are found on what are aptly called carnivorous caterpillars. They can also use their true legs to defend themselves from predators or parasites. They are like tiny hunters with deadly little weapons.

6. Flannel Caterpillars Have An Extra Pair of Prolegs

Flannel caterpillars are the larvae of flannel moths, a family of insects that occur in North America and the New World tropics. One of the distinctive features of flannel caterpillars is that they have seven pairs of prolegs instead of the usual maximum of five found in most other caterpillars. The extra pair of prolegs may give flannel caterpillars an advantage in locomotion and stability. They move by inching forward each set of legs from the back to the front, creating a wave-like motion. They can also use their prolegs to grasp objects or defend themselves from predators by curling up into a ball.

The photo featured at the top of this post is © Jay Ondreicka/Shutterstock.com