Bats and dolphins, which are not even closely related and look so different from each other, both have what we call “echolocation,” an extraordinary ability among mammals.
Scientists recently discovered that the similarities are related to the physical and genetic levels of the bats and dolphins as they had been through many genetic transformations separately which resulted in their unusual bio-sonar systems.
Echolocation is used by animals by emitting calls out to the environment and listening to the echoes of those calls that goes back from various objects close by. They use this ability to identify and locate objects.
“Convergent Evolutions” is how scientists termed the event happening to bats and dolphins. The physical resemblance between the analogous shapes of the wings of the bats and birds is another example.
The researchers wondered if several genetic steps which bats and dolphins underwent on their evolution were the same. They compared and evaluated the complete genetic evolutions of 22 different kinds of mammals, which include both non-echolocating and echolocating bats, dogs, bottlenose dolphins, mice, horses and humans.
“Strong and significant support for convergence among bats and the bottlenose dolphin was seen in numerous genes linked to hearing or deafness, consistent with an involvement in echolocation. Unexpectedly, we also found convergence in many genes linked to vision: the convergent signal of many sensory genes was robustly correlated with the strength of natural selection,” researchers wrote in a report published in Nature.
The scientists discovered roughly 200 genomic regions where the bat and dolphin adaptations associated to echolocation overlapped.
Even if bats and dolphins share several genetic changes associated to echolocation, the courses are different. Bats use their vocal cords to produce sounds, as the majority of mammals do. Dolphins, on the other hand, make their clicks in an extraordinary structure in their heads (phonic lips) and are modulated and focused by the melon, a fatty organ in their foreheads.
Regardless of their dissimilarities, the study shows that both bats and dolphins evidently required in making essential genetic transformations in making the radical shift from relying on their vision to relying on their ears.
