12. Etruscan Shrew
It goes by other names, the Etruscan pygmy shrew, or the white-toothed pygmy shrew is the smallest known mammal in terms of mass. It measures up to 4cm, not including the tail, and weighs about 1.8 grams. This tiny creature tends to eat twice it’s weight as it has a very fast metabolism and also tends to move very fast as well. They are commonly found in warm and moist places, from Europe and North Africa up to Malaysia.