The badger is a burrowing omnivore from the family Mustelidae, which also includes weasels and otters. It is the mascot of Hufflepuff House.
In CS11 Harry heard Professor McGonagall shouting at a student who had turned his friend into a badger.
Hufflepuff's Cup was engraved with a badger. (HBP20, DH26)
Uric the Oddball once showed up to a Wizards Council meeting with a dead badger on his head, having listened to fwooper song for three months. (FB)
Badgers are known for their tenacity, and while not regarded as aggressive, they can be ferocious when they are attacked. As such, they are often underestimated, much like the students of Hufflepuff House. In North American mythology they are also known for their determination, independence and persistence.