Why do emperor tamarins have such big moustaches?

David Waite, keeper at ZSL London Zoo

Emperor tamarins are known for their big moustaches, but scientists are still not sure what they are for. The most likely reason is to help groups of tamarins see each other in the dense rainforest. The bigger and more visible the moustache, the more likely they will be seen by other members of their group, and this ensures that everyone is accounted for.