What parts of the body would a person want to have in greater numbers? An extra pair of hands could certainly come in handy. Perhaps a second pair of eyes on the back of the head wouldn’t hurt either. But what about a second tongue? Just thinking about it is a bit unsettling. Meanwhile, for lemurs, having a double tongue is more of a benefit than a nightmare. So where does this adorable primate hide its second tongue?
If you take a closer look at a licking lemur, you can spot a small white structure with a pointed, brush-like tip beneath its main tongue. This is the sublingua, or the secondary tongue of the lemur.
Unlike the primary tongue, the sublingua lacks taste buds, so it doesn’t play a role in the sensory perception of food. Shortly after the secondary tongue of lemurs was first described in the early 20th century, some scientists believed it served no function at all and was merely a vestigial structure. However, researchers have since concluded that the sublingua is closely linked to another unusual anatomical feature of lemurs: the dental comb. This consists of a set of six long teeth located at the front of the animal’s lower jaw. These two canines and four incisors resemble a comb due to the small gaps between them, as reported by IFLScience. Like a hair comb, this one is used for grooming.
But the lemur’s sublingua does more than just tackle pesky tangles. The second tongue helps lemurs remove food particles, debris, and fur from the crevices of the dental comb. Just like in our teeth, all sorts of things can get stuck in the gaps of this primate’s mouth. While we might reach for dental floss or a toothpick in such situations, lemurs utilize their “built-in” tool: they clean their mouths with the sublingua.
So, it’s safe to say that the second tongue makes perfect sense for lemurs. Effective self-care is crucial for these primates. Grooming and cleanliness help Madagascar’s endemics establish close social bonds. It’s no surprise: no one wants to be friends with someone who can’t keep their comb clean. However, the masterful use of the sublingua isn’t the only way lemurs create and maintain social connections. It turns out that, just like humans, lemurs enjoy a good gossip session.