15 Most Alien Looking Caterpillars on Earth

Given that caterpillars are not themselves a species but just the in-between stage from butterfly or moth egg to pupa and then finally adult, they have made quite a name for themselves, especially as pests. Some of them are also so alien looking that one wonders where in the world they have come from.

Caterpillars belong to the Lepidoptera order, the insect order that is made up of butterflies and moths. Though the appearance and colouring of caterpillars can vary widely, common to most are their tubular, segmented bodies with three pairs of true legs and ten abdominal segments. They can have up to four pairs of prolegs (fleshy, stubby little structures coming out from the middle of the abdomen), making them quite the creepy crawlies.

Not all caterpillars look alien or even cute. As a rule of thumb – the more colourful and fuzzy a caterpillar is, the more likely it is to sting if touched. So, if in doubt, hands off!

The caterpillar of the Pale Tussock moth (Calliteara pudibunda), common in England and Wales, is usually greenish-yellow with ample tufts of hair.

Mugshot of a truly alien-looking critter:



The saddleback caterpillar is one of the most common slug caterpillars and its sting is the severest, so watch out for this critter! Good that its distinct shape and markings make it hard to miss, though it is only about 1 inch long. Both ends of the caterpillar’s body are dark brown with brown “horns” that bear numerous spines. The middle of the body is green with a whitish margin and an oval spot in the middle, giving it the appearance of a saddle or blanket and therefore its name.


Giddy up if you dare!



Butterflies and moths are at their most vulnerable stage as caterpillars because they can’t just fly away and escape. Therefore, they have developed some interesting, one might even say bizarre, defenses. These include blending in with the environment, false faces with bright eye spots, mimicking other insects, and bright colouring that warns potential predators not only that they taste bad but could also be poisonous.

This green alien is a native of the Philippines and seems to have taken the fake eye spots to an extreme, making its “face” quite large and scary. Normally, a caterpillar’s face is much smaller and not on the second abdominal segment.


Scaring potential predators – extraterrestrial ones?



Speaking of caterpillar faces, the next one seems to have used a full make-up kit. This fact and its four little striped “goatees” make this caterpillar a truly bizarre specimen.


Yo, what’s up in the hood?


Stinging rose caterpillars (Parasa indetermina), also called rose slug caterpillars, are truly colourful characters that can be found in the forests of the eastern United States. Apart from orange, white and purple lines, the caterpillars also don bright yellow, spined tubercles, all warning potential predators: Stay away, I’m poisonous! This is also true for humans who might give picking up the less than one-inch-long critter a second thought as their sting is as severe as that of the saddleback caterpillar.


Mirror, mirror, on the wall, who is the brightest of them all?


The caterpillar of the Great Orange Tip butterfly (Hebomoea glaucippe) can be found in Asia and Australasia. The specimen below is trying to look spiky and stern. The blue-black eyes and raised head give it an almost snake-like appearance.


Snakecharmer, anyone?



The next example shows that fuzzy does not equal poisonous and non-fuzzy safe, oh no!

The caterpillar of the Pipevine Swallowtail butterfly is an interesting fellow because it feeds on plants of the Pipevine family that are poisonous to most other insects and animals. This caterpillar not only eats the plant without being harmed but also stores its poison inside and becomes poisonous itself the more it eats. Fully grown caterpillars are about two inches long and black with red spines.


Not an adult yet but positively poisonous looking!



The caterpillar of the Red-tailed moth (Dasychira pudibunda) is truly a fuzzy and funny looking critter, if not really an alien in the West in that it can be found throughout Europe and North America. Its nickname is ‘hop dog’ because hop pickers used to frequently find it among the crops.


Hop doggy dog:


The home of the Evening Brown butterfly caterpillar (Melanitis leda bankia) is the Brisbane area in Australia. Its body is green with white spots and its head is of a darker geen shade with black horns. The specimen below sports dark red horns.


Grab the caterpillar by the horns:



The caterpillar of the Flannel moth (Megalopyge) is more or less exactly that – a very fuzzy fur ball.


The very fuzzy caterpillar:


Among the non-stinging and therefore harmless caterpillars, the larva of the Imperial moth (Eacles imperialis) probably looks the scariest with its green, fuzzy body and yellow horns, arms and, er, butt. The caterpillar is between 3-4 inches long and a native of the southern United States.


Doesn’t this specimen look like a tiny Chinese dragon?
Red, white, blue and spiky - a patriotic French caterpillar:



As readers of EG’s article of Moths with Multiple Personalities will know, the Cobra moth (Attacus atlas) is not only one of the largest moth out there, but also uses wingtips that look like cobra heads to scare away predators. No wonder then that this master of disguise also shows up as a pretty impressive caterpillar: It is bluish-green with bluish and yellow spines and covered with a fine white powder.


Peaceful as long as there’s enough food around:



The most striking feature of the Tailed Emperor caterpillar (Polyura pyrrhus) is its four-horned head, which makes it look truly alien. Like the Evening Brown Butterfly, it also calls the area around Brisbane in Australia its home. Click here for more scary mugshots of this unusual caterpillar.


Not your average caterpillar:



The caterpillar of the Dryas iulia butterfly can be found from Brazil to Texas, in the summer even as far north as Nebraska. It has an orange underside and is black on top with long, spiky spines, daring predators to bite into it.


Is it Halloween yet again?


And finally, a caterpillar that is no caterpillar. This fuzzy branch is part of a willow caught at North Creek Park in Snohomish County, WA.


Do caterpillars grow on shrubs?