What is the smallest mammal by weight?

The smallest mammal by weight is the Etruscan shrew (Suncus etruscus), which weighs only about 1.8 grams (0.063 ounces). Despite its tiny size, it has a high metabolism and needs to eat up to twice its body weight in food each day to survive. The Etruscan shrew is found in parts of Europe, Africa, and Asia and primarily feeds on insects and other small invertebrates. Its small size and rapid movements make it one of the most agile and energy-efficient mammals.