Flies don't have mouths to chew or bite food. They vomit on food to help them break it into tiny particles and then suck up the vomit again
A jellyfish's mouth is also its anus.
Hippopotami are able to open their mouths 180 degrees
The Mouth is integral to erotic pleasure in the sensual act of eating, as well as in the acts of kissing, licking and sucking.
The Mouth is a potent symbol of both consumption and its control, combining in the one site sensuality/nature (the tongue and the tastebuds) with rationality/culture (the organ of speech).
The Mouth is the ambiguous locus of two oralities: one articulates the voice, language... the other satisfies a need, the ingestion of food for survival first of all, but also for a pleasure that becomes juxtaposed with the value of nourishment'.

Your mouth is dirtier than a toilet seat
The Mouth is an useless instrument to some people,-in as far as it renders ideas audible, but of special service for rendering victuals invisible.
The Mouth is the grocer's friend, the dentist's fortune, the orator's pride and the fool's trap.