The Laotian Rock Rat - Living Fossil

Happy Monday, everybody! After a week spent talking about sharks I figured it might be nice to focus on an animal today that most likely won’t ever get a minute on television, despite making a comeback after a vacation of at least a few million years! Meet the Laotian rock rat: living fossil.

Animals and plants that are considered to be living fossils are those that are nearly identical to a species only known from fossilized remains with no other living relatives. Cockroaches and aardvarks are two commonly known animals that are referred to as living fossils. The recently discovered Laotian rock rat may fit this description as well, but there is some debate.

Discovered in Laos in the late 1990’s, the Laotian rock rat was first thought to be so distinct from all living rodents that it was placed in a new family called Laonastidae. However, in 2006 this classification was debated by biologists and it was instead suggested that the Laotian rock rat is a relative of members of the ancient Diatomyidae family which has been extinct for 11 million years. The rat is commonly placed in this family now. If this is indeed the case, the Laotian rock rat would join sixteen other mammals that were once thought to be extinct only to be rediscovered, though none have been thought extinct for nearly this long. This type of occurrence is known as a Lazarus taxon.

The Laotian rock rat appears different from other living rats. Despite the similar appearance and coloring of its body, it has the long and bushy tail of a squirrel. Most are about 15 inches in length with a third of that coming from the tail and a weight of about a pound. These rats have thus far only been found in the Khammouan Province of Laos. Though little is yet known about this newly-discovered species, their limited range and pressure from trapping has led the ICUN to label them as endangered.