Kangaroos were mammals common to Australia. Indeed, a young Western Australian lad named Harvey met the Tenth Doctor soon after stumbling across a kangaroo with glowing eyes. It turned out that the animal had been affected by the recently-fallen Skylab. (PROSE: Bennelong Point)
On at least one adventure with the Eleventh Doctor, Abigail Pettigrew went to Uluru and was photographed in front of a kangaroo crossing sign. (TV: A Christmas Carol)
Immediately after regeneration, the Seventh Doctor's brain was addled, and he unwittingly altered several common metaphors. He claimed that Melanie Bush had the "mind of a kangaroo" before she reminded him that people with great memories were said to have the "mind of an elephant." (TV: Time and the Rani)
Kangaroos were among the animals on board the Ark in circa 10,000,000. (PROSE: The Ark)
