8 Things You Didn't Know About the Creepy-Cute Aye-Aye

Aye-aye close up
dennisvdw / Getty Images

Aye-ayes are peculiar, arguably cute, long-fingered lemurs that live in the only place lemurs ever live, on the African island of Madagascar. They're recognized by their big, bushy tails, equally large eyes and ears, and rodent-like teeth. They have long, slender fingers that help grip the trees where they live. The locals see them as a curse, but to scientists, they're an anatomical wonder worth bringing back from an endangered status. Here are a few things you may not know about the elusive Malagasy creature.

1. Aye-Ayes Are the World's Largest Nocturnal Primate

Aye-ayes are large compared to other nocturnal primates

San Diego Zoo

Although they share an order with such sizable creatures as gorillas and orangutans, aye-ayes are the largest primates of the nocturnal variety. An average adult grows to be about 3 feet long and weigh around 5 pounds. Its tail alone can span a whopping 2 feet, longer than its body. Other nocturnal primates include night monkeys, galagos (aka "bush babies"), lorises, and tarsiers.

2. They're Related to Humans

Aye-aye on a tree

Anna Veselova / Shutterstock

Although they seem to differ greatly from humans in their physical traits — with the enormous ears, bushy tails, and all — aye-ayes are categorized in the same order as humans. They're a very strange-looking cousin of the perhaps more familiar ring-tailed lemur, which shares about 93 percent of its DNA with humans. Still, though, scientists say the aye-aye has evolved to be more similar to squirrels.

3. They're the Only Primates That Use Echolocation

The aye-aye's ears are so big for a good reason

Denver Zoo

Echolocation is the ability to locate an object by listening to sound waves bouncing off it. The aye-aye uses this method to track down insect larvae inside branches and tree trunks. It will tap the tree with its slender fingers, then rip away the bark and use its elongated middle finger to fish out food, a behavior called percussive foraging. The aye-aye is the only primate to use echolocation.

4. Aye-Ayes Are Solitary Creatures

Aye-ayes spend most of their lives alone

Zoological Society of London

Nocturnal animals often lead solitary lives and the aye-aye is no exception. According to the American Association for the Advancement of Science (AAAS), they spend their days sleeping and nights foraging, rarely socializing with other creatures. Unlike other primates, they haven't been observed grooming each other and their territories hardly overlap except when males move into a female's dominion.

5. Scientists Once Thought They Were Rodents

Baby aye-aye at the San Diego Zoo

San Diego Zoo

It took a while before researchers placed the aye-aye in the primate family. Before that, the critter's continuously growing incisor teeth — characteristic of rodents — justified its previous position in the order Rodentia, which it shared with beavers, chipmunks, squirrels, muskrats, porcupines, prairie dogs, and marmots. Now, the unique animal is said to be a highly specialized lemur.

6. They Have 'Pseudothumbs'

Aye-ayes have pseudothumbs

David Haring / Duke Lemur Center

Researchers from North Carolina State University found that aye-ayes have an extra digit that could help them grasp objects and grip branches. These "pseudothumbs," as they've been called, are tucked near each wrist and contain bone, cartilage, and three distinct muscles that move them, as well as their own fingerprints.

"The aye-aye has the craziest hand of any primate," Adam Hartstone-Rose, lead author and associate professor of biological sciences, said in the report. "Their fingers have evolved to be extremely specialized—so specialized, in fact, that they aren't much help when it comes to moving through trees. When you watch them move, it looks like a strange lemur walking on spiders."

7. The Locals Think They're Evil

The locals think aye-ayes are evil spirits

javarman / Shutterstock

Cute to some, the sight of a wide-eyed aye-aye — hanging from a jungle tree with its skeletal finger, at night — is enough to freak someone out. It's no wonder why the Malagasy people have historically considered them to be bad spirits. According to National Geographic, many see them as "an omen of ill luck. For this reason they often have been killed on sight. Such hunting, coupled with habitat destruction, have put aye-aye populations at-risk."

8. The Aye-Aye Is in Trouble

Aye-ayes are an endangered species

Cincinnati Zoo & Botanical Garden

Hunting is part of the reason the International Union for Conservation of Nature and Natural Resources (IUCN) lists aye-ayes as an endangered species. In fact, less than 100 years ago, the critters were thought to be extinct. They became a key focus for conservationists when they were rediscovered in the '50s, but due to the frequent killing of aye-ayes (to protect crops and defend from their believed "evil spirits") and the mass destruction of Madagascar forests, they were moved to the endangered category in 2014.