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

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

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

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 (like all primates) 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

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

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. Although they have been seen foraging in pairs, they have not been observed grooming each other like other primates, and their territories hardly overlap except when males move into a female's dominion.

5. Scientists Once Thought They Were Rodents

It took a while before researchers placed the aye-aye in the order Primates. 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. Since, it's been found that the aye-aye's traits are so different from both rodents and lemurs that the species is now in a family and genus of its own.

6. They Have 'Pseudothumbs'

According to a 2019 report published in the American Journal of Physical Anthropology, 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. Lead author and associate professor of biological sciences Adam Hartstone-Rose called the aye-aye hand "the craziest hand of any primate," noting that their fingers look almost like spiders as they move through trees.

7. The Locals Think They're Evil

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 they're thought to be unlucky. The Malagasy people have long considered them to be bad omens, summoners of evil, and the innocent aye-ayes are often killed for their unfavorable reputation, too.

8. The Aye-Aye Is in Trouble

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.