Boar

From TARDIS Index File, the free Doctor Who reference.

Boars were a type of omnivorous mammals that were the ancestors of domesticated pigs.

The boars had gone extinct in England, but they were later reintroduced in 1987. This occurred during a massive storm in Kent, when a farm that raised wild boars was damaged and the boars were allowed to escape. Some of these boars came to the house of the Doctor, and eventually evolved into the intelligent Boar race. (EDA: Mad Dogs and Englishmen)