Weird Animal Hands: Demon Primate, Flappy-Armed Frog, More

For humans, hands are a pretty important body part. We do almost everything with them, and our opposable thumbs are a singular point of primate pride.

But we’re not the only dexterous species out there. Here’s a look at some other animals with intriguing hands—or appendages that act like hands by letting them get a grip. (Read more about amazing hands in National Geographic magazine.)


No animal can give the world the finger like the aye-aye of Madagascar.

A photo of an Aye Aye.
An aye-aye in Madagascar’s Masoala Peninsula. Photograph by Thorsten Negro, Imagebroker, Corbis

Probably the weirdest of all us primates, the aye-aye’s hands look certifiably villainous, with its long, bony, clawed Nosferatu fingers—especially that extra-long middle one.

It uses that to tap-tap-tap on trees to detect hollow places in the bark where delicious insects might be. When it finds one, it bites through the wood and—yoink!—uses that wicked long finger to snap its prey.

While they are only a bellwether of death for their prey, sadly, some people in Madagascar believe ayes-ayes are a death omen or demon.

“If one is seen near a settlement it must be killed, and even then the only salvation might be to burn down the village,”  Hilary Bradt wrote in Bradt’s Travel Guide: Madagascar.

Helen’s Flying Frog

It was a frog on a log and now it’s on a blog.

Jodi Rowley, an amphibian biologist at the Australian Museum in Sydney, spotted what’s now called Helen’s flying frog in 2009 while on a hike through a lowland forest close to Ho Chi Minh City, Vietnam’s biggest ‘burg. (Related: “‘Fantastic’ New Flying Frog Found—Has Flappy Forearms.”)

A photo of a Helen’s Flying Frog.
Helen’s flying frog was found in a lowland forest in southern Vietnam. Photograph by Jodi Rowley, Australian Museum

And check out those mitts! Their webbed hands are similar to those of Wallace’s flying frog, a slightly larger flying frog that can glide up to 50 feet (15 meters) from tree to tree in its jungle habitat of Malaysian Borneo. Flaps of skin on the forearms also help these frogs glide.

Rowley named the frog after her mother in appreciation for her support, a sweet gesture any mom would love.


Moles are adorable (perhaps with the exception of the star-nosed mole).

Mole hands, however, are deeply weird, which may be appropriate because they’re designed for digging. Those large, flat forepaws act like spades, and those long fingernails are turned outward to excavate the underground burrows in which moles find refuge and food. (See “Moles Smell in Stereo to Find Food, Dodge Predators.”)

A photo of an eastern mole.
An eastern mole emerges from its tunnel. Photograph by Ken Catania, Visuals Unlimited, Corbis

A 2011 report from the University of Zurich offers one reason those hands dig so well: Moles are polydactyl, which means they have an extra finger, in their case a sickle-shaped spare thumb.

This extra thumb doesn’t have moving joints, and the mole rests on while it digs, giving that shovel-like hand some extra power. The study showed that the bone develops in the embryonic mole later than the other fingers, from a bone in the wrist.

High six!


Talk about clingy: Geckos can adhere to just about anything because the lines on their hands and feet are covered with hairs called setae, which are in turn covered with tips called septulae.

A photo of a tokay gecko.
Microscopic hairs on a female tokay gecko’s feet adhere to surfaces. Photograph by Robert Clark, National Geographic

Septulae are so tiny that they can bring the gecko into almost complete contact with the surface it’s on. This increases the Van der Waals force, a weak electrical force that holds many things together, including most organic solids. That’s why geckos cling like a worrisome ex.

This Spider-Man stickiness has inspired some incredible scientific endeavors.

Canadian engineers and researchers from the European Space Agency have created a gecko-inspired adhesive pad that could make it possible for robots to scale the outside of a spacecraft to do repairs or research. (See “Watery Gecko Grip Could Lead to Stickier Tape.”)

MIT professors Jeff Karp and Robert Langer, founders of Gecko Biomedical Company, have developed a gecko-inspired adhesive bandage and a surgical glue with Pedro del Nido of Boston Children’s Hospital. Both innovations have the potential to be less invasive in closing human incisions than traditional sutures are.


Your mother warned you about those dates with wandering hands. For the hoatzin bird of South America, it’s not someone else’s hands, but its own hands—or claws—that have meandered to a peculiar, but quite helpful, place. (See interesting illustrations of hands.)

Photo of a baby Hoatzin.
A baby hoatzin’s wing has claws that help it climb. Photograph by M. Williams Woodbridge, National Geographic

Hoatzin chicks are the only birds known to have claws on their wings (they lose them in adulthood).

These oddly placed claws come in handy, both for climbing around in trees and for pulling themselves back onto their perches if they fall into the water.

Look, Ma—weird hands!

Follow Liz Langley on Facebook and Twitter.

Liz Langley is the award-winning author of Crazy Little Thing: Why Love and Sex Drive Us Mad and has written for many publications including Salon, Details and the Huffington Post. Follow her on Twitter @LizLangley and at

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (

Social Media