If you’ve been to a Meet the Keeper program at Lemurs, you may have heard someone ask if the Red Ruffed Lemurs have “thumbs” or “fingers” on the ends of their tails. The answer is “no”; the little bit of naked tail that sticks out in varying lengths from the normally furry tails of our lemurs is a by-product of over grooming. The Red Ruffed lemurs will occasionally groom their tail tips by licking, chewing or rubbing at them with their fingers and subsequently, have removed tufts of fur from the ends. The naked bit of tail can bend and curl just like the rest of their tails, but it isn’t prehensile.

So what exactly is “prehensile”?

It’s defined as an appendage or organ found on a vertebrate animal that has the ability to grasp or hold.

Though the definition seems simple enough,  it’s not always so black and white. Think about the tail of a Virginia Opossum or the lips on a rhino or donkey. They have the ability to grasp or manipulate objects, but can’t really hang on tightly. In those cases, the appendage is considered “semi-prehensile.”

Here are some examples of prehensile appendages in the animal world: new world monkey tail (like Spider Monkeys), octopus arms, chameleon feet, prehensile-tailed porcupine tails, Giraffe tongues, primates with a thumb have prehensile hands and sygnathidae tails.

Here are a few more “semi-prehensile” appendages: elephant trunk tip, camel lips and snake tails.