Yes, Lemurs Really Do Have Two Tongues – But Why?

Do you ever wish you had more of one particular body part? An extra pair of hands could come in well, handy, as would having another pair of eyes in the back of our heads – but what about two tongues? That might sound like the stuff of nightmares to us, but for lemurs, it’s far more helpful than horror-like.

If you’re wondering where on Earth lemurs are stashing a second tongue, take a look at one of the many delightful pictures on the internet of lemurs doing a “mlem”. Peer a little closer, underneath the main tongue, and there should be a small, white feature that might look pointed or brush-like – that’s the sublingua (literally meaning “under tongue), their secondary tongue.

Unlike the primary tongue above it, the sublingua isn’t part of the sensory experience; it doesn’t have tastebuds. Not long after it was first described back in the early 20th century, some scientists thought that it didn’t have a purpose at all, believing it to be a vestigial structure.

Nowadays, however, it’s widely thought to be related to another unusual part of lemur anatomy – the toothcomb . This is a set of six long teeth found at the front of a lemur’s lower jaw, featuring two canines and four incisors, which does in fact look a bit like a comb thanks to small gaps between each tooth.

Like its namesake, the toothcomb is used in grooming, although it does more than get rid of pesky knots. This structure can also help lemurs remove bits of debris from their own and other lemurs’ fur.

Trouble is, like our own teeth, stuff – in this case, debris and fur rather than a bit of spinach – can get stuck in the gaps. We might turn to some floss or a toothpick in this instance, and the sublingua is the lemur equivalent, keeping their built-in grooming tool nice and clear.

It’s a feature that makes sense considering how important effective grooming is to lemur life; so-called “social grooming” is a way in which the bonds between individuals and groups of lemurs can strengthen. No one’s going to want to be your pal if you can’t keep your comb clean.

Luckily, making good use of a toothcomb and sublingua isn’t the only way for a lemur to create and maintain strong bonds – it also turns out that, like many of us, they also love a good gossip .