Which Came First: Echolocation or Fruit Bats?

Apart from flight, perhaps the most impressive bat feature is their ability to “see” with sound by using echolocation. But fruit bats in the family Pteropodidae (flying foxes) lack this sonic superpower, and that sets up two possible scenarios for the trait’s evolution: either it arose separately in the close cousins of these fruit bats and all other bats, or the ancestor of all bats could echolocate, and these fruit bats lost the ability. “This has been a long-standing question in bat biology,” explains Dr. Santana—one that these six genomes may have finally answered.

Comparing physical features and genetic ones has yielded different answers in the past, Dr. Santana explains, but the six highly complete genomes were able to provide clearer insights. Instead of having to zero in on known genes and compare them between species, the Bat1K team was able to compare whole genomes and look for areas that differ between the various bats. That allowed them to uncover mutations present only in echolocating bats, including a tiny duplication in part of a hearing-related gene that no one had noticed before.

Since these genetic features were identical in all echolocating bats—including in previously published genomes—they concluded that two independent origins for echolocation was extremely unlikely.