Badger pirates were life forms artificially created by humans. They often worked as mercenaries or pirates.
Biology
The badgers were made from the DNA of badgers and humans. They were humanoid, but with muscular bodies, badger-like heads and furry bodies. Badger pirates were grown in test-tubes. (PROSE: The Pirate Loop)
Culture
Badger pirates tended to have the culture of humans, since they were generally used as slaves and servants.
The Badgers of the Mandelbrot Sett had exaggerated pirate personae. They wore golden earrings, spoke with stereotypical pirate accents and wore skulls and cross-bones. The golden earring was used to pay for their funerals. They resolved issues with duels. (PROSE: The Pirate Loop)
Technology
The Badgers were armed with guns that engulfed their target in pink light before making them vanish. The Badger force was carried around space in a huge mothership. When they neared their target, the Badgers would be released in small pods that would smash against the hull of the targeted ship. The Badgers would then force an entry. (PROSE: The Pirate Loop)
History
The badgers were created after the extinction of the badger. They were generally employed as hired thugs and mercenaries.
The Mandelbrot Sett, a ship of pirate Badgers, was sent to attack the Brilliant in the 40th century to get its experimental drive. When they attacked the ship, it activated the drive, causing the ship to be stuck in time. Three pirates, Dashiel, Jocelyn and Archibald, were able to get onboard before the drive was activated. Because of an incomplete time loop, they were unable to permanently kill anyone and began to learn about the finer things in life. Eventually, they almost became friends of the crew.
Eventually, the other ships made it through the time loop and attacked the ship, killing the passengers, taking the crew back to the Mandelbrot Sett and destroying the Brilliant. When the Tenth Doctor tried to convince them to give up their mission, they killed him. However, the Brilliant's engine had been hooked to the TARDIS and the time loop had been extended to include the Mandelbrot Sett. Everyone was brought back to life. Seeing that fighting would be useless and having been told of life on the Brilliant, the pirates left the Mandelbrot Sett for the Brilliant. With the time loop repaired, they were allowed to party on the Brilliant forever. (PROSE: The Pirate Loop)