Bats aren't very loved in our culture. They are referred to as 'the bird(s) of the Devil.' Evil creatures like Vampires take the form of Bats... Bats can be a symbol of black magic, witchcraft, but also of cunning and of wisdom.
In most other traditions however, the Bat has a different, and usually more positive meaning. In Buddhist tradition, as well as in the Shamanic traditions, as in the tradition of the Native American Indians, the Bat is a symbol of reincarnation, of Rebirth.
"Bat embraces the idea of shamanic death. Shaman death is the symbolic death of the initiate to the old ways of life and personal identity.(...)
It symbolizes the need for a ritual death of some way of life that no longer suits your new growth pattern. This can mean, a time of letting go of old habits, and of assuming the position in life that prepares you for rebirth, or in some cases initiation. In every case, Bat signals rebirth of some part of yourself, or death of old patterns. If you resist your destiny, it can be a long, drawn out or painful death. The universe is always asking you to grow and become your future. To do so you must die the shaman's death." (Jamie Sams & David Carson, the Medicine Cards.)