Fox

Foxes were small mammals abundant in the United Kingdom and other places on Earth.

They were the objectives of hunts held in Britain that were both sport and aristocratic tradition. During the Third Doctor's exile on Earth, the Bristol police were once forced to keep the peace between fox hunters and those who opposed the practise. Because of the high tensions between the groups, the police had a difficult time of it. (PDA: Rags)

When foxes died in public places, it could be the local police's job to remove the body. One British constabulary was clued into an alien invasion ultimately countered by the Third Doctor and UNIT because of a dead fox discovered on public ground. (DWAN: The Mind Extractors)

Much later in the Doctor's life, Hex, Ace and the Seventh Doctor found stuffed foxes in Joe Hartley's taxidermy studio. (BFA: Night Thoughts)

Cultural references to foxes
Foxes were commonly used in the names of pubs and inns in the United Kingdom. The Fourth Doctor, Harry Sullivan, Sarah Jane Smith and UNIT used the Fox Inn as a temporary headquarters in Scotland while dealing with the Zygon threat in Loch Ness. (DW: Terror of the Zygons) The Fancy Fox was a pub that Amy Pond, Rory Williams and the Eleventh Doctor used as a kind of base while on an adventure in the town of Foxton. (NSA: The Way Through the Woods)