The red-crested tree rat was thought to be extinct but was recently rediscovered after 113 years of not being seen! Researchers have been trying to find this animal, when it simply showed up at a nature reserve. They live in Columbia, South America, and are about the size of a guinea pig.
The below photographs are a couple of the first pictures ever taken of the animal:
Pictures from Animal Planet.
I love the long fuzzy tail!
To read the story of their rediscovery see Conservation International.