Steele is the main antagonist of Balto, the first film of the trilogy. He is a selfish and aggressive Alaskan Malamute and the lead dog of the fastest dogsled team in Nome. Steele often bullies Balto over his wolf heritage.
Obviously, don't nominate any human characters. Hybrids like Cheetah or The Lizard are okay, as are shapeshifters with one set animal form (eg Professor McGonagall.)