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. (ST: Stanley)

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 mythically large gorilla. This movie spawned imitations, such as Mighty Joe Young. (NA: Happy Endings) There was also some literary use of gorillas. Lucy Hayward developed a life-long fear of gorillas from a book she had read as a child. It was this fear which eventually killed her in a room on the Minotaur's "hotel". (DW: 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. (ST: To Kill a Nandi Bear)

Gorilla could also be an epithet or insult, indicating a person — usually male — who was ugly or brutish. Rose Tyler described Darren Pye as looking like a shaved gorilla, "only not as handsome". (NSA: Winner Takes All)

Alien equivalents
The Doctor, John and Gillian encountered alien sabre-toothed gorillas on a planet that resembled Earth. (TVC: The Sabre-Toothed Gorillas)