A new study has found that bats have an impressive vocal range of seven octaves, far surpassing ours as humans, and even “growl” like death metal singers.

We’ve always known that bats produce high-pitch noises as echolocation rather than sight, but researchers made a surprising discovery when they filmed bats’ larynges for the first time. In addition to vibrating very thin membranes above their vocal folds, the research team discovered that another set of folds on their larynx vibrate as well, producing very low-frequency sounds. 

Humans have similar vocal folds, however they only appear to be used by death metal and throat singers to make a throaty growl noise. Humans call these “false vocal folds” as they have no function in normal speech.

Researchers theorized that the false vocal folds of bats may have evolved this way because bats need to communicate over long distances and can do so more effectively with lower frequencies, while echolocation requires higher frequencies.

It’s unsure what the bats are communicating with these noises, but humans often hear them around bat roosts, and many have speculated that it could be associated with aggression or annoyance. 

The nibble of a lion

Researchers have discovered a new branch on the tree of life, and it’s made up of predators that nibble their prey to death. 

The predators fall into two groups called nibblerids and nebulids, which together make up a new ancient branch on the tree of life called Provora. Nibberids nibble chunks off their prey using tooth-like structures, whereas nebulids eat their prey whole. 

These microbial predators have been called the lions of the microbial world by the University of British Columbia researchers who published the study, due to being numerically rare yet important to their ecosystem. 

On the tree of life sitting under domains, and above kingdoms, are branches of creatures called supergroups. The organisms in these groups share a common ancestor and are characterized by traits. The Provora branch is the latest supergroup to be discovered.

To discover the new microbes, researchers collected water samples from marine habitats across the globe. It was found that there were tiny organisms with two flagella or tails in the water that convulsed in place or swam very quickly. When these were present, almost all the others disappeared after just one or two days, leading to the conclusion that they were being eaten. 

Fight club

Which would win in a fight: an ankylosaur or… an ankylosaur? These armoured dinosaurs — resplendent with spikes along their flanks and a formidable club-like tail — were thought to have evolved their defensive weaponry to protect themselves from predators like tyrannosaurs. However, an exceptionally preserved specimen of ankylosaur Zuul crurivastator (from the Royal Ontario Museum’s collection) has paleontologists thinking these hench herbivores may have been battling something else… each other.

Detailed study of a fossil ankylosaur, led by Victoria Arbour of the Royal BC Museum, revealed that the spikes on its flanks had been broken and rehealed while the dinosaur was still alive. And the battle scars were consistent with the damage we’d expect from another Zuul’s tail club, suggesting that ankylosaurs used their tails to engage in ritualized combat for territory or mates.

While these armoured animals may well have used their tails to defend themselves from predators in a pinch, it’s likely their club-like tails evolved through sexual, rather than natural, selection — that is, tail clubs enabled better access to mates, like moose with big antlers. 

Bee-lining for Canada