Animals rarely appear in the BBC series. For vampires animals are uninteresting. They need human blood. Werewolves hunt animals during a fullmoon night. After such a night they often wake up next to a dead a animal, which they have killed in their werewolf form. Animals don't react differently towards humans, werewolves in human form or vampires. It's unknown whether animals can sense the presence of ghosts or not.
Most of the animals that are seen in the series are pets or animals that have been killed by a werewolf.