Bats are wild animals and should therefore not be kept as pets. The act of keeping one of these winged creatures as a pet will cause it to experience fear, inappropriate and damaging nutrition, loneliness. Furthermore, wild bats are capable of living over 25 years but unfortunately bats that are kept as bats rarely survive for more than a year.
Bats are also protected by laws at many levels. Regulations govern the taking of bats from captivity, as well as any exchange between individuals or organizations. The transfer of bats is also carefully regulated by the CDC. USDA permits from the Animal Health Inspection Service are required and special permitting regulations also now apply at the state level. There are also interstate laws that prohibit transport of these animals without special authority.
In order to keep a bat as a pet one must acquire the necessary state and local permits for native wildlife. Bats are not to be transported within the United States without a CDC permit. Even when individuals have this type of permit bats can only be transferred to an institution that is bona fide sanctuary, zoological or scientific organization or a registered establishment that has approved facilities and/or certified education programs.
Although only about 1% of bats actually carry the rabies virus, bats and other wild animals are still considered to be a rabies vector species. Special administrative codes under the Department of Health and Zoonosis Control address this issue. The U.S. Centers for Disease Control and Prevention for biohazard regulations that pertain to bats can be accessed online and provide valuable information regarding the issue.
As you can see, bats are difficult to keep as pets and illegal to keep as pets in most cases. It is also not fair to them, and they have a much greater chance of living a long and healthy life when left alone in the wild where they belong.