Calomyscus

Mouse-like hamsters, also called brush-tailed mice or calomyscids, are a group of small rodents belonging to the genus Calomyscus found in Syria, Azerbaijan, Iran, Turkmenistan, Afghanistan, and Pakistan. They are found in rocky outcrops and semi-mountainous areas in desert regions. The generic name Calomyscus derives from the Greek word kalos, meaning 'beautiful'; the full name translates to "beautiful mouse".

The mouse-like hamsters are not true hamsters, but represent an early split from the rest of the mouse-like rodents. They were once thought to be hamsters based on the shape of their molars, but they lack the cheek pouches, flank glands and short tails of the true hamsters. The closest relatives of the mouse-like hamsters may be the extinct Cricetodontidae. Because of their seemingly early break from the rest of the mouse-like rodents, mouse-like hamsters have been placed in a family of their own, Calomyscidae, and have been referred to as living fossils.