The bumblebee bat is about 29–33 millimetres (1.14–1.30 in) in length and 2 grams (0.07 oz) in mass). This is the reason for its common name "bumblebee bat". It is the smallest species of bat. The Etruscan shrew is lighter (1.2–2.7 g) (0.042-0.095 oz).