All species of bat develop ears designed for echolocation, even if they are not all able to utilise the sense.
That's according to research by a leading Irish scientists and colleagues from China, which has turned existing theories about development of echolocation in bats, well, upside down.
The study suggests echolocation evolved once in bats and then became lost, rather than evolving more than once.
The research was prompted by evidence gathered from genetic analysis and from fossils showing bats that use laryngeal or voice box echolocation have not evolved from a homogenous group.
As a result, scientists have long wondered whether echolocation evolved more than once or evolved, then became lost in certain species.
Founding Director of the Centre for Irish Bat Research at University College Dublin, Professor Emma Teeling and colleagues tested the theories by examining how the inner ear develops in foetal and new born bats.
Using seven species of bat, five of which have the ability to echolocate, as well as five other species of mammal that do not echolocate, they studied the development of the cochlear - the bones housing the inner ear.
The results, published in the journal Nature Ecology and Evolution, show all of the various species of bats showed rapid early development of the cochlear, which is usually bigger in adult mammals that use echolocation.
The other mammals, however, did not show the same level of rapid growth.
Interestingly though, cochlear growth in the bats unable to see with their ears slowed down considerably after the initial expansion, and went on to grow cochleae that are similar to those of other animals.
As a result, the authors have concluded that echolocation in bats evolved from one single origin.