Bat

Bats are the only mammals capable of true flight. With extremely elongated fingers and a wing membrane stretched between, the bat’s wing anatomically resembles the human hand. Almost 1,000 bat species can be found worldwide. In fact, bats make up a quarter of all mammal species on earth!

Description
The Bat is the only mammal that can fly. Bats have modified hands and arms that serve as wings capable of sustained flight. They have been flitting across the night skies since the Eocene Epoch, some 50 million years ago. In all this time, the physical features of these animals have changed very little. Fossil specimens from Europe and North America are nearly indistinguishable from living forms. There are nearly 1,000 living bat species, accounting for almost a quarter of all mammal species. The Bat is a relatively fast flight unit and has a good defense for a vulnerable flyer. Combine with a strong offense creature for a powerful and extremely mobile attack force. It also capable of revealing and area in the fog of war with it's sonar pulse ability.