Scientists have found evidence that bats have existed for 50 million years. Some scientists believe it may have been even longer.
When trying to understand how bats have lived, scientists study living animals. But no one was around 50 million years ago to study the beginnings of bat life. Scientists use "fossils" (old bones) to try to learn about how bats evolved.
The earliest fossils of bats that we've found look very much like the skeletons of bats today. This tells us that bats haven't changed much over the years.