Elephant

An elephant was a large herbivorous herd animal found on Earth. They were notable for their long trunks, which comprised over 10,000 muscles, and their ivory tusks. Types of elephant included the African elephant, Asian elephant, (PROSE: The Schoolboy's Story) and Indian elephant (TV: The Ark)

Their tusks were made of ivory, (COMIC: Witch Hunt) a fact which resulted in them becoming endangered by Robert Zierath's time. (PROSE: The Schoolboy's Story) In the 21st century, they were infected by a retrovirus and mutated into a rudimentary intelligence capable of using tools against their hunters. (PROSE: The Two Jasons)

Encounters with elephants
The Doctor and their companions occasionally encountered elephants.

Among the prizes the First Doctor won in a game of backgammon against Kublai Khan in 1289 were thirty-five elephants with ceremonial bridles. (TV: "Assassin at Peking")

Elephants were one of the animal species brought on board the Ark in circa 10,000,000 to escape the destruction of Earth. Dodo Chaplet pointed an Indian elephant out to the First Doctor and Steven Taylor and they proceeded to pet it. (TV: The Ark)

The Second Doctor and Jamie McCrimmon once used a herd of animals – which included elephants – to stampede a group of Quarks. (COMIC: Jungle of Doom)

Tegan Jovanka rode on an elephant to find the Fifth Doctor and Nyssa, rescuing them from wolves in India during the 1920s. (AUDIO: The Emerald Tiger)

The Seventh Doctor and Ace saw elephants living in the Ngorogoro Crater in March 1926. (PROSE: Prelude Birthright)

In about 120 AD, the Tenth Doctor learned that Roman authorities kept elephants as a part of a menagerie that included leopards, giraffes and a wide range of other, chiefly African animals. Some of the beasts were kept for hunting, and others were used to face off against prisoners in local arenas. The Doctor was incensed by the practice, because he knew it would lead to the extinction of several of the species. (PROSE: The Stone Rose)

On 4 February 1814, the Twelfth Doctor and Bill saw an elephant walking across the surface of the frozen Thames during the last frost fair. (TV: Smile, Thin Ice)

In April 1861, Leela and Abasi encountered an illusory elephant in the Congo. Leela determined that it was not real as it had no smell. (AUDIO: The Ghosts of Gralstead)

Whilst in India in 1947, the Doctor and Donna Noble travelled with Mohandas Gandhi and his party by elephant. Donna was amused by the rolling motion caused by the elephant's gait. Consequently, both she and the Doctor had a hard time controlling their laughter. As was customary in India, these "transport elephants" were highly decorated with flowers, bells, and a howdah. (PROSE: Ghosts of India)

There were elephants in the zoo that Martha Jones went to when she was young. (PROSE: The Last Dodo) They were also used as performers, with several working at the International Circus. (TV: Terror of the Autons)

Cultural references to elephants
In Voyager's dream world, a waterfall existed that was bordered by two elephant statues. (COMIC: Voyager)

When talking to Davros about logic, the Fourth Doctor said "All elephants are pink, Nellie is an elephant, therefore, Nellie is pink!". When he asked if it was logical and Davros agreed, the Doctor and Tyssan corrected him that elephants weren't pink. (TV: Destiny of the Daleks)

Human folklore stated that elephants never forget anything. It was a running joke between the Sixth Doctor and his companion Melanie Bush that she had the memory of an elephant. (TV: The Ultimate Foe, AUDIO: The One Doctor, TV: Time and the Rani, AUDIO: Unregenerate!, The Warehouse, A Life of Crime)

A life-sized model of an elephant's head was in Spellman's Magical Museum of the Circus in 2009. (TV: The Day of the Clown)

Salvador Dalí once painted with long, thin legs. (AUDIO: The Forbidden Time)

Jo Grant thought that the sound of the TARDIS dematerialising was like that of the trumpeting of a thousand mad elephants. (PROSE: Doctor Who and the Doomsday Weapon, Doctor Who and the Green Death) Gilgamesh thought it sounded like a dying elephant. (PROSE: Timewyrm: Genesys) Cindy Wu called it the "sexy elephant noise" and the "elephant-and-ancient-piano-dance sound". (COMIC: Old Girl)

Captain Jean-Luc Picard likened the prospect of the USS Enterprise-D engaging a Cyberman Fleet to a mosquito against a herd of elephants. (COMIC: Assimilation²)

Nardole played with a toy elephant in Grant's home. (TV: The Return of Doctor Mysterio)

Penny Carter's girlfriend always told her she had the "memory of an elephant". (AUDIO: SOS)