The Etruscan Pygmy Shrew, or white-toothed pygmy shrew (Suncus etruscus), weighs in at about 1.8 grams (0.063 ounces) and averages 4 centimeters (1.6 inches) in length excluding the tail. Known as the smallest mammal by mass, the pygmy shrew has an incredibly fast metabolism and eats 1.5 to 2 times its body weight each day.