descends to a lower domain of rebirth after a human life, rather than immediately going on to another human birth, or going up to a higher domain. In the lower domains, such as the animal domain, it is a very slow and difficult process to accumulate enough merit to achieve a human rebirth once again, so it may be countless lifetimes before one has another chance. Tiryagyoni Domain The Tiryagyoni domain (alternately spelled Tiryag-yoni or tiracchānayoni) (also known as the Animal domain) is based on strong mental states of stupidity and prejudice cultivated in a previous life or lives. Buddhists believe that this domain is the domain of existence of the nonhuman animals on the Earth. Although humans and animals live in separate domains of existence, they can still see each other because their domains are so close to each other in the vertical cosmology, just as the Devas and Asuras can see each other despite being in separate domains. Preta Domain The Preta domain (also known as the Hungry Ghost domain) is a rebirth based on strong possessiveness and desire which were cultivated in a previous life or lives. The sentient beings in this domain are known as "hungry ghosts". They are constantly extremely hungry and thirsty, but they cannot satisfy these needs. In Tibetan versions of the Bhavacakra these beings are drawn with narrow necks and large bellies. This represents the fact that their desires torment them, but they are completely unable to satisfy themselves. Naraka Domain The Naraka domain (also known as the Niraya domain or the Hell domain) is a rebirth based on strong states of hatred cultivated in a previous life or lives. The sentient beings in Naraka stay there until their negative karma is spent, at which point they are reborn into another domain. The Wheel of life The Bhavachakra or "Wheel of Life" is a popular teaching tool often used in the Indo-Tibetan tradition. It is a kind of diagram which portrays these realms and the mechanism that causes these samsaric rebirths. In this depiction, the realm of the Devas is shown at the top, followed clockwise by the realms of the Asuras, the Animals, Naraka, the Pretas, and the Humans. Close examination will show that the Buddha is shown as being present in every one of these realms. Characteristics In Mahayana and Vajrayana Buddhism, there are some sayings reflecting a tradition that