Hi everyone! I hope you all had a good week!

I read a very interesting article about a study dedicated to finding what types of evolutionary forces help shape animals. A group of biologists at the University of Washington researched the diversity of bat skulls. The researchers used scans of skulls of over 200 bat species to look into what physical changes have occurred over millions of years. In a paper published on May 2, they reported that the two main factors of evolution in bats is echolocation and diet.  

Using 3-D scans of jaw shapes for 191 species and scans of the cranium of 202 species, scientists compared the skull differences of bat lineages to study how diets affected lower jaw shapes. The experiment showed that early on, around 58 million to 34 million years ago, the main factor affecting bat skull shape was echolocation. This is because echolocation has been a part of bat survival for that long. Echolocation helps bats in hunting and foraging in settings with low light. Since they first began using echolocation, different bat species have evolved to have more species-specific echolocation techniques. Some bats, like mega bats, even echolocate through their noses instead of their mouths!

More recently in bat evolution, around 26 million years ago, diet became a more dominant driving force in skull shape evolution. Evidence of this can be found in bat species such as leaf-nosed bats which have very intricate designs to their skulls, which help with echolocation and eating.  

Because of all the variety in bat skull shapes, the study showed that diet and echolocation don’t affect skull shape evolution uniformly. Scientists did learn that diet was the stronger evolutionary driver in bats with stronger lower jaws, whereas echolocation affected the cranium.

If you would like to read more about this study, you can find the article here.