Which is the smallest mammal?

Two tiny animals share the title of smallest mammal. The Etruscan shrew, found from southern Europe to Asia, is the lightest, usually weighing only about 1.8 grams. The bumblebee bat, or Kitti’s hog-nosed bat, from Thailand and Myanmar, is the smallest by length, with a body only about 3 centimetres long. The bat was described in 1974 and is named after Thai biologist Kitti Thonglongya. To stay alive, the Etruscan shrew has an extraordinarily fast metabolism, with a heart that can beat more than 1,000 times per minute, and it must eat constantly.