Ilin Island cloudrunner
The Ilin island cloudrunner was a rodent found on Earth. It was worth 2000 points in the I-Spyder Book of Earth Creatures if it was spotted.
The Tenth Doctor once used the cloudrunner as a way to cheer up Martha Jones. When she became angry at humanity for having killed off the quagga, the Doctor used the cloudrunner as an example of the good in her species. He noted the wonder in the very naming of the speices, calling it "brilliant" that some human would invent the name "cloudrunner" for "fluffy rodents sitting about hight up in the mountain treetops" instead of going for the more mundane "tree rats" or "mountain mice". (NSA: The Last Dodo)