The Bothans were used as spies in the Galactic Civil War.
The Bothans originated on the planet of Bothawui. Due to the nature of how their civilization developed (lacking mounts and pack animals), bothan states early on turned to covert operations to acheive their political ends. They have a curious ability to become invisible and undetectable, and to regenerate health.
The Bothans joined the Rebel Alliance shortly after the construction of the Death Star. In accordance to their ability to become undetectable by radar, they were employed as spies. A small team of Bothans were responsible for stealing the Death Star plans.
The Bothans have a small history of refusing to use standard-issue blaster rifles, and instead employ the use of incinerator pistols. As the incinerator pistol is a Bothan's primary weapon, they have been proved upgradeable to the Incinerator Cannon. The only weapon they have used issued by the Rebel Alliance is the Thermal Detonator.