In Greek mythology, Cerberus or Kerberos (Greek Κέρβερος, Kérberos or Sürbürǔs, the aemon or ker of Erebos) was the hound of Hades, a monstrous three-headed dog with a snake for a tail and snakes down his back like a mane, whose analogs in other cultures are hellhounds. Other hell hounds included Orthus, his two-headed brother. Cerberus guarded the gate to Hades and ensured that spirits of the dead could enter, but none could exit (additionally, no living person was to come into Hades). Among his siblings are Chimera and the Hydra. He is the offspring of Echidna and Typhon. In Dante's Inferno, he is described as having a human head. This symbolizes the possibility of Cerberus being more human than animal.