Rabbit

A rabbit was a small mammal. The Fourth Doctor once asked K9 if he wanted to chase some rabbits. Adric had to explain to him that this meant they were going somewhere. (DWA: Inter-Galactic Cat)

Boa constrictors preyed on rabbits and ate them whole. (DW: The Time Monster)

A giant rabbit was a delegate at the Third Inter-Galactic Peace Conference. (DW: Frontier in Space)

On Dagomere, giant rabbits were know to dig large tunnels. (BFBS: The Tree of Life)

Both the Bunnoids and the Leppos were rabbit-like in appearance. (ST: Planet of the Bunnoids, EDA: Frontier Worlds)