Biochemical Soul Musings on Nature, Science, Evolution, Biology, and Education

Adaptation of the Week – The Aye-Aye’s Freaky Finger (I’ve Been Cursed by an Aye-Aye!)

"In the gloom it came along the branches towards me, its round, hypnotic eyes blazing, its spoon-like ears turning to and fro like radar dishes, its white whiskers twitching and moving like sensors; its black hands, with their thin fingers, the third seeming terribly elongated, tapping delicately on the branches as it moved along."
- Gerald Durrell, The Aye-aye and I

Aye-Aye Lemur (photo credit: ZSL London Zoo)

Imagine that you're a nocturnal prosimian primate in Madagascar some odd thousands of years ago. You've made a living eating insects under the bark of trees using powerful teeth to chew your way to your prey. There are no woodpeckers living on this giant island, thus many trees contain pre-packaged boreholes filled with tasty grubs. You can get to the grubs, but it requires some trial and error and alot of wasted gnawing energy.

Luckily some of your offspring are even better at finding the tree grubs, and even more adept at getting the little insects out of the holes. Generations pass, and before you know it, your descendants have become masters of the art of tree grub prospecting.

They have become the magnificent Aye-Aye lemur (Daubentonia madagascariensis)!

I was recently privileged enough to see the Aye-Aye in person at the Duke Lemur Center in Durham, NC (one of  a small handful of places in the US where they can be seen).

In fact, I was cursed to death by one.

Aye-Aye Hand (photo credit: David Haring)

You see, the Aye-Aye has become so adept at finding insects in trees because of one singularly peculiar adaptation: it's third finger has become a skeletally thin and extraordinarily long hollow-space-detecting, insect-pulling device.

The Aye-Aye uses its long finger first to find the insect larvae - it gently taps the tree, using it's enormous and independently rotating ears to hear the hollow reverberation. Once found, it tears into the hollow area with its teeth. Now the finger shows its prime utility; the Aye-Aye inserts the skinny appendage into the hole, using its sharp claw to pull out the grub. In addition, it's knuckle joint is much like our ball-and-socket joints in our hips, making it all the more dexterous!

However, the Aye-Aye's adaptations to the tree grub lifestyle must be seen to be truly appreciated.  Check out this amazing video, care of ARKive and BBC Motion Gallery.

And this one from 8thContinent:

Unfortunately, many of the Malagasy people of Madagascar do not quite see the beauty in this unique ability. The Aye-Aye is surrounded by several superstitious myths, including the belief that if an Aye-Aye points at you (which they are wont to do), you are cursed to death. Generally, if you see an Aye-Aye or if it shows up in your village - you and/or your village are cursed to death. As such, the Aye-Aye is often killed on sight.

I, on the other hand, considered it a blessing when we entered the Lemur Center's nocturnal habitat, the red lights turned on, and an Aye-Aye immediately began swiveling its long pointy adaptation at me and my wife. It was actually quite thrilling, considering that the tour guide had just told us about the myth.

However, with the help of the Duke Lemur Center's conservation and education efforts in Madagascar (and many other such efforts), some of the Malagasy people seem to be changing their views. The Aye-Aye is still highly endangered, but hope remains...

Previous Adaptations of the Week:

1. Timber Rattlesnake Camoflage