At the center of every Wheel of Life are a cock, a snake and a pig, which represent greed, anger and ignorance. In Buddhism, greed, anger (or hate) and ignorance are called the "Three Poisons" because they poison whoever harbors them. These are the forces that keep the Wheel of Life turning, according to the Buddha's teaching of the Second Noble Truth.
The circle outside the center, which is sometimes missing in depictions of the Wheel, is called the Sidpa Bardo, or intermediate state. It is also sometimes called the White Path and the Dark Path. On one side, bodhisattvas guide beings to rebirths in the higher realms of Devas, Gods and Humans. On the other, demons lead beings to the lower realms of Hungry Ghosts, Hell Beings and Animals.