Gorilla

Gorillas were a type of ape native to Earth.

Earth gorillas
The Doctor, his companions and associates occasionally ran across gorillas in their travels. For instance, the Fourth Doctor and Leela once visited the London Zoo at a time when its animals were running free. They saw a gorilla grooming one of the zoo keepers. (PROSE: Stanley)

In 1911, Nathaniel Whitlock had a gorilla on his property in Suffolk. He paid £150 for it. (AUDIO: Moonflesh)

In 1936, Charley described the Slaverings as a "cross between a silver-backed gorilla and Mr Hyde." (AUDIO: The Shadow at the Edge of the World)

The Eleventh Doctor and Rory Williams visited New York City in the 1930s and found it was being menaced by a giant gorilla. However, the Doctor said that it wasn't a giant gorilla, but the city itself had been shrunk. (COMIC: The Doctor and the Nurse)

Breeds
Amongst the specific breeds of gorilla known were mountain gorillas.

Cultural references to gorillas
Gorillas were often the subject of fiction. One of the more popular films of the 20th century was King Kong, which depicted the adventures of a giant gorilla. This movie spawned imitations, such as Mighty Joe Young. (PROSE: Happy Endings) There was also some literary use of gorillas. Lucy Hayward developed a life-long fear of gorillas from a book which she had read as a child. It was this fear which eventually killed her in a room on the Minotaur's "hotel". (TV: The God Complex)

It was also common for people to dress up as gorillas. Harry Sullivan, for instance, used a gorilla costume from the TARDIS to help fool a tribal shaman in Nyasaland into believing that the tribal chief had captured a mythical "Nandi Bear" inside the ship. (PROSE: To Kill a Nandi Bear)

Behind the scenes
The gorilla from The God Complex that frightened Lucy Hayward in the hotel room was a role played by actor Roger Ennals.