In addition to being able to fly, bats are relatively unique in having the capability to echolocate. Echolocation in bats, just like in a submarine, involves directing sounds out into the environment and detecting the reflecting sound waves. By comparing where the reflecting sounds come from, bats flying in the dark can estimate their distance from prey items and obstacles.
Most bats are relatively small, have tiny eyes and can echolocate by producing clicks from their larynx (voice box). The Old World fruit bats (Pteropodidae) tend to be large, have much bigger eyes and cannot echolocate, with the exception of the rousette fruit bats (genus Rousettus) which can produce tongue clicks.
Rousettus aegyptiacus – Egyptian fruit bat
For many years, evolutionary biologists noted that the echolocating bats were anatomically very similar to each other, to the exclusion of the Old World fruit bats. The former were referred to as microbats, being typically smaller, and the latter were known as megabats. However, once scientists began examining their DNA, they found out that some of the echolocating “microbats”, including the minuscule bumblebee bat
are actually more genetically similar to the large-bodied, non-echolocating megabats
than to other echolocating species.
Though this was first discovered in 2000 by Emma Teeling and colleagues  using six genes with >6,000 letters of DNA, more recent studies using almost 2.4 million letters of DNA have confirmed these earlier results .
Why the discrepancy between anatomy and DNA? An evolutionary explanation is that the Old World fruit bats are adapted to a new lifestyle that no longer requires echolocation. Many fruit bats rely on their large eyes for navigation during flight, and since they are typically fruit or nectar eaters they presumably do not need to echolocate to detect their immobile ‘prey’!
Questions for Creationists
If God created bats and their DNA, why is it that some small, tiny-eyed, echolocating bats are much more genetically similar to large, non-echolocating bats with big eyes than other small bats? If God created the same animals with the same building blocks, wouldn’t all echolocating bats be more genetically similar to each other?
1. Teeling, E. C., Scally, M., Kao, D. J., Romagnoli, M. L., Springer, M. S., & Stanhope, M. J. (2000). Molecular evidence regarding the origin of echolocation and flight in bats. Nature, 403(6766), 188-192.