amnhnyc:

The smallest mammal that ever lived could be sitting right on your shoulder, and you’d hardly know it. Batodonoides vanhouteni (model pictured) lived about 50 million years ago in what is now Wyoming, and was so small that it could climb up a pencil. It also weighed as little as a dollar bill! Several slightly larger species of these mini-mammals lived between 55 and 42 million years ago, but they are now all extinct. Its closest living relatives are modern-day shrews and moles.
Photo: randychiu