Here’s a great idea for a super-power: what if by merely emitting a sound, you could detect nearby friends and enemies in the way the sound echoes? Echoes. Echoes.

For many species of bats and dolphins, echolocation isn’t a super-power but a necessity. It allows these animals to hear predators and prey without seeing them in the dark skies or cloudy oceans. This adaptation evolved separately in these mammals—a great example of convergent evolution.

Scientists at Queen Mary, University of London were curious how this type of convergent evolution looked at the genomic level. So they compared the complete genomes of 22 mammals, including new sequences of four bat species, to look at how echolocation is expressed in the genes.

To perform the analysis, the team had to sift through millions of “letters” of genetic code using a computer program developed to calculate the probability of convergent changes occurring by chance, so they could reliably identify “odd-man-out” genes.

Remarkably, they found genetic signatures consistent with convergence in nearly 200 different genomic regions! “We had expected to find identical changes in maybe a dozen or so genes but to see nearly 200 is incredible,” explains Queen Mary team member Joe Parker. “We know natural selection is a potent driver of gene sequence evolution, but identifying so many examples where it produces nearly identical results in the genetic sequences of totally unrelated animals is astonishing.”

Although many of the gene region similarities are in genes involved in hearing, which the team expected, others are all over the place, reports ScienceNOW:

…some genes with shared changes are important for vision, but most have functions that are unknown.

The team published their findings last week in Nature.

“These results could be the tip of the iceberg,” says group leader Stephen Rossiter. “As the genomes of more species are sequenced and studied, we may well see other striking cases of convergent adaptations being driven by identical genetic changes.”

So perhaps not a super-power, but a regular occurrence…

Image: Greg Hume

Bats are not scary– in fact, what’s not to love about them? Echolocation, mosquito-eaters, they’re mammals and even kind of cute. (Well, maybe not this newly discovered tube-nosed fruit bat.)

But wait, there’s more. Recent research shows that their flight is much more complicated than that of birds and insects. Discover has a great online video demonstrating the process. And bats’ flight could inspire future aerospace technology design, according to the New York Times:

Further study of bat wings could help aerospace engineers develop tiny autonomous airplanes that are as flexible and acrobatic as bats… Today’s aircraft are large and have stiff wings, more similar to birds than to bats.

Other current research shows that bat echolocation goes beyond hunting—it’s also used to identify other bats.

More recent news about bats is sadly very scary. As cold winter weather begins to arrive, scientists are incredibly concerned about the further spread of White Nose Syndrome (WNS), caused by a fungus, that has killed over one million bats since 2006 in the eastern US. Current research suggests that the fungus disrupts the bats’ hibernation, causing them to awaken early, behave oddly, and lose critical fat reserves, resulting in death. One particular species, the little brown myotis, could quickly become extinct in some areas.

Eastern caves are being shut to stop the spread of the fungus. Though it travels from bat to bat, humans likely spread WNS, as well. It is possible that humans brought the syndrome to the US, since the fungus is found in European caves (European bats are not affected by WNS).

Because of the number of insects bats eat each day (more than half their weight), the effects of life without bats could be very dramatic, especially on agriculture. From a recent Popular Science article:

“Without bats, people are going to end up using more pesticides, there will be more water and soil contamination, more human contamination,” [Boston University researcher Tom] Kunz said.

You can help. Send a message to Interior Secretary Ken Salazar to get more funding for scientists studying and hoping to stop WNS. Build your own bat house to help protect your own bat-neighbors (with instructions from Bat Conservation International).

The world would be a very scary place without bats.

Scientists from Brown University and Japan report that echolocating bats traveling in large groups minimize sound wave interference by tweaking the frequencies of the sounds they emit — their broadcasts — to detect and maneuver around obstacles. The scientists also found that bats make mental templates of each broadcast and the echo it creates, to differentiate one broadcast/echo set from another. According to James Simmons of Brown, “They’ve evolved this, so they can fly in clutter. Otherwise, they’d bump into trees and branches.”

Meanwhile, in Germany, researchers from the Max Planck Institute for Ornithology found that the greater mouse-eared bat uses an internal compass and the Earth’s magnetic field to navigate in the dark. The fact that the greater mouse-eared bat does not use echolocation, even when hunting for food, makes this finding even more surprising.

The scientists don’t know how the bats detect the magnetic field, but according to New Scientist, “By exposing bats to a short pulse of skewed magnetic field during and after sunset,” they found that exposure “during sunset confused the bats, causing them to fly in the wrong direction, while experiencing it after the sun had set had no effect. This is strong evidence that the bats rely on the magnetic field while flying at night, after calibrating it by noting where the sun has set.”

So add radio broadcaster and astronomer to the list of bats’ amazing feats!

Creative Commons image by Vermin Inc