Animal

An animal was a kind of lifeform. Mammals were a class of animal.

As noted by the Third Doctor, all animals had brains of some sort. (TV: Invasion of the Dinosaurs)

Around 10,000,000 AD, the Earth was in danger of falling into the Sun. The entire human, Monoid, animal and plant population of the planet was loaded onto the Ark, a gigantic spacecraft, to take them to a new home on Refusis II. (TV: The Ark)

Proximans were a semi-intelligent, empathic telepathic species of social animals, with a type of primitive group mind described by the Eighth Doctor as a co-ordination. They lived in nests. (PROSE: The Face-Eater)

On Harmony, all animal life (or, at least, those raised for food) was wiped out in a plague. (PROSE: Planet of Bones)