Many fish, especially species that live in lakes and coral reefs, are equipped with enlarged, rubbery lips. Such a pronounced piscine pout has evolved many times independently among unrelated species, but only now have scientists got an idea of why.
A study of African cichlids has found that fat-lipped species also tend to have thin, pointed snouts, which make them look even poutier. This particular arrangement of facial features enables fish to extract prey from crevices more easily.
The pointed snout can be inserted into nooks and crannies, while the fleshy lips create a seal with the rock, which enables the fish to suck the prey out.
Main image: Black grouper fish © Getty images