Crocodiles were a species of reptile.
In ancient Egypt, Thoueris controlled the crocodiles in the River Nile with her ring. The Eighth Doctor took her ring and used it to turn the crocodiles against her. (COMIC: The Power of Thoueris!)
In Karabya, India on 31 December 1926, the Fifth Doctor and his companions Nyssa, Tegan Jovanka and Turlough were forced to cross a den of crocodiles. Tegan referred to one of them as "an overgrown handbag." (AUDIO: The Emerald Tiger)
In India in 1947, a gigantic crocodile tried to attack the Campbells' house, but Major Daker shot it dead. (PROSE: Ghosts of India)
On an unnamed planet, the First Doctor was nearly attacked by a crocodile, but drove it off with some magnesium powder. (COMIC: The Didus Expedition)
A lake on an unnamed planet was infested with crocodiles. The first of the tests of Trefus required that one of the fair-haired people to swim across this lake. Saul completed this test when the Second Doctor used explosives to temporarily stun the crocodiles. (COMIC: The Tests of Trefus)
One planet was inhabited by six-legged, telepathic crocodiles. (PROSE: The Crocodiles from the Mist)
Crocodiles lived on an island in the Divergent Universe. (AUDIO: The Next Life)