In some branches of Buddhism (e.g., Tibetan Buddhism), hungry ghosts are associated with one of the six realms--Realm of the Gods, Realm of the Jealous Gods, The Human Realm, Realm of the Hungry Ghosts, The Animal Realm, and the Hell Realm. Hungry Ghosts are envisioned as creatures with huge distended stomachs but narrow straw-like mouths. Hence they cannot take in enough food to satisfy their monstrous appetites--a fit metaphor for unbridled desire. It is said that the Human Realm is the only one that holds the possibility of enlightenment.