BBC:

The giggling sounds of a hyena contain important information about the animal's status, say scientists.

In the first study to decipher the hyena's so-called "laugh", they have shown that the pitch of the giggle reveals a hyena's age.

What is more, variations in the frequency of notes used when a hyena makes a noise convey information about the animal's social rank.

What a disappointment is to learn that the laughter is meaningful and not some demonic expression of the true absurdity of existence, of being in a world that is the way it is—full of misery, pain, and throats that heartily swallow the little joy that is to be had. At the end of the universe, one expects to see some laughing teeth, gums, tongue, and a throat to nothingness.