Wildlife

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.)

Aye-Aye

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

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

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!

Gecko

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.

Hoatzin

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!

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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 www.lizlangley.com
  • Jennifer jones

    I do enjoy the animal stories and photo’s. I will be enjoying a cruise in April on the National Geographic Orion. Lots of coral and fish .. Can’t wait! Jennifer J.

  • Robert C Brooke

    The aye-aye reminds me of the goblins in the comic strip Heavenly Nostrils.

  • Davis Drazdovskis

    Hi, nice article 🙂
    Just a suggestion to remove the “only” part in hoatzin chicks description. There is quite a bunch of birds which have claws, spurs, spikes etc… Basically more or less rudiment, but still the first digit finger which is quite visible and often quite used 🙂
    Cheers,

    Davis

  • nikki

    I don’t think Hoatzin claws are oddly placed. Paleontologists believe that birds come from dinosaurs and that the genes responsible for their front leg claws switched off when their front legs turned to wings. Obviously this is not the case with haotzins they still have their claws! Of course it might be that the genes responsible for the claws either got reactivated or that they developed some new genes for them. Some paleontologist also believe that in the future scientists might be able to switch these genes on in chickens and along with some other generic modifications develop some new dinosaurs. Unfortunately I cannot remember where I read the article mentioning this!

  • Valeria

    Aye-aye looks like a nerdy pianist, who just finished performing Rachmaninov’s music..

  • mario

    Il y a bien de bizarres d’animaux…c’est exactement comme chez les “”” humains “”” !?!?!

  • herry bourhans

    What this animal?….hmmmm….. amazingg

  • maha

    ilove this kind of animal i enjoy waching them

  • Liz Langley

    Thanks @Davis Drazdovskis!

    You are right, that was a misplaced “only.” After reading your comment I found other birds with wing claws, like the turaco (here’s a link: http://tinyurl.com/kqx3ybf), so thanks for the observation!

  • purita

    scary hands

  • Rogier

    Silkies do have also clawss on their wings
    They are the most closely related birds to the dinosaurs (did anyone else see that episode of Nova where scientists are trying to make dinosaurs using silkie genes?)
    For a picture see here http://www.backyardchickens.com/forum/uploads/37921_100_2239.jpg

  • yaldamahboub

    They are amazing…

  • Liz Langley

    @Valeria

    😀
    Brilliant!

  • Patricia Seaton

    Very interesting article and I appreciate the humor! It’s always fun to learn new things in the world of creatures.

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