Which beast with three heads guards the circle of gluttons?

The beast with three heads that guards the circle of gluttons is Cerberus. In Dante’s Inferno, this monstrous watchdog stands at the entrance to the third circle of Hell, where the gluttonous are punished.

Dante adapts Cerberus from Greek and Roman mythology, where he guards the gates of the Underworld and prevents the dead from escaping. In classical stories, he is commonly described as a three-headed dog with a serpent’s tail and snakes around his neck. He is also famous as the creature captured by Heracles during the hero’s twelfth labor.

In the poem, Cerberus reflects the sin of gluttony: he is ravenous, filthy, and constantly snarling. The souls in this circle lie in a freezing, foul rain, while Cerberus tears at them. Virgil quiets the beast by throwing handfuls of earth into his mouths.

A common mix-up is confusing Cerberus with Geryon, another creature Dante encounters later. Geryon represents fraud, while Cerberus specifically belongs to the third circle and its gluttonous inhabitants.