Fox

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

History
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 practice. Because of the high tensions between the groups, the police had a difficult time doing it. (PROSE: Rags)

When foxes died in public places, it might 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. (PROSE: The Mind Extractors)

After the evacuation of London during Operation Golden Age, Mike Yates saw a fox in Picadilly and listed this among the benefits of the city's abandonment when talking to Sarah Jane Smith. (TV: Invasion of the Dinosaurs)

Much later in the Doctor's life, the Seventh Doctor, Ace and Hex found stuffed foxes in Joe Hartley's taxidermy studio in 2006. (AUDIO: Night Thoughts)

In the 30th century, foxes were present on the human colony planet of Avalon. (PROSE: The Sorcerer's Apprentice)

In the 40th century, foxes were aboard the colony ship that eventually became the Twist. When the ship malfunctioned, the foxes evolved into the Foxkin. (COMIC: The Twist)

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. (TV: 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. (PROSE: The Way Through the Woods)