This document summarizes three animals that are now extinct - the dodo bird, saber-toothed tiger, and woolly mammoth. It provides key details about each animal's physical characteristics and behaviors. The dodo was a flightless bird that became extinct in the late 1600s. The saber-toothed tiger preyed on large mammals like bison and lived in forests and grasslands. The woolly mammoth was a huge mammal with long hair and tusks that lived in northern climates and ate grasses and plants.