At barely 2" long (about 47 mm, to be exact), the Pygmy Jerboa is one of the smallest mammals in the world. There are a few different species spread out across Central Asia and China, but they really love this little guy in Kazakhstan! They have him on postage stamps there! Scientists believe their tiny size is due to the species separating off from the larger rodent family about eight million years ago or more, and settling in the lands it now lives in today.