om nom nom or singing for one’s supper

Via the resplendent Nag on the Lake, we learn that gorillas and other primates compose happy little songs of contentment to accompany their meals.
There are two distinct types of humming, one steady and seemingly like a dinner-bell (or saying grace) to signal to the group that it is now time to eat, and the other highly idiomatic and personalised that’s always varied and seem to express pleasure in the repast. This behaviour has been observed both in the wild and in zoos, but outside of captivity, social norms seem to prevail and only the dominant males, the silver-backs, sing—whereas in zoos, all gorillas do so. Studying these vocalisations may help researchers learn more about the development of language and socialisation. Listen to recorded samples of the hums at the link above.