Check out the article on tracing the evolution of bats. This relates some of the information from a publication in Science about affinities of microbats and megabats. Generally, the mibcrobats use biosonar megabats don’t. But picking out the family relationships has been a puzzle. This study asserts that the megabats “nest” within several of the microbat lineages.
While all this is cool stuff, including tracing the paleobiogeography of bats, there are some rough spots in the media hype.
“Bats are a spectacular group of mammals, with a combination of two remarkable specializations that you don’t see in any other land mammals: flight and echolocation,” Springer said.
Yes, bats are a spectacular group of mammals.
Yes, bats are the only mammals capable of sustained flight. Other mammals do have some pretty impressive gliding capabilities.
But Springer is off into the weeds with the claim that bats are the only terrestrial mammals to use biosonar. Shrews, rats, some badgers, and the aye-aye (Daubentoniidae) use forms of biosonar. Their use of biosonar is certainly less polished than that seen in many bat species, but they do use it. (Other species that use biosonar besides “the usual suspects” of bats, whales, and dolphins include oilbirds and cave swiftlets, showing that biosonar is not a strictly mammalian adaptation, either.)
There is a tendency in media reports for scientists to be quoted making statements that pump up the significance of their research. This is an all-too human quality, and perhaps we can’t expect reporters either to give all the caveats that someone might add to a statement that needs qualification, or to check out some of the sweeping claims that aren’t part and parcel of the actual data and analysis being reported. The simpler forms of biosonar noted in other species illustrate an important point, that this adaptation is not as limited in nature as Springer is reported to have stated.