The Red-Crested Tree Rat may be the rarest rat in the world. It is known through descriptions, a single pelt in the New York Museum of Natural History from 1898 which was classified in 2005 as Santamartamys rufodorsalis, and now from two volunteer biologists working in Columbia for ProAves Foundation. The rat is nocturnal and assumed to be terrestrial rather than arboreal. It walked up to the researchers one night while they were standing on their porch about to turn in for the night. They sent pictures to Paul Salaman of the World Land Trust-USA who just a few years earlier had organized an unsuccessful attempt to find the elusive rat.
The Red-Crested Tree Rat is known only from Sierra Nevada de Santa Marta in Columbia. This area is a cloud forest, a type of tropical rainforest characterized by almost constant canopy-level clouds. Nothing is known about the rat’s life history or habits. Thus far the only thing known about it is that it is found in a small area, as the recent citing is only 3 miles from there the 1898 pelt was collected, and that the living rat probably weighed ab
out a pound, had a white and black tail and the red mane of fur from which it gets its name. The rat is the only organism within its genus and according to Salaman could basically be a living fossil, a rodent that has changed little in tens of millions of years of being isolated in its little cloud forest.