New Study Reveals Microscopic Inner Ear Structures of Bats Dictate How They Echolocate

Researchers have found that there is a presence of extra neurons and specialized ear structures inside bats which helps them to echolocate. In a study, experts determined how bats differ in their echolocating abilities.

They examined microscopic inner ear structures of bats from 19 of the 21 known bat families. The new study also sheds light on our understanding of the evolution of echolocation, which only a few species are capable of.

"This is the first physical evidence we have to support what genetic data tell us about the split of bats into two major groups," says Bruce Patterson in Science Daily, one of the study's authors and the MacArthur Curator of the Field Museum.

Why Some Bats Can't Echolocate

There has been a time when scientists classified bats into two groups, Megachiroptera and Microchiroptera, with the former being vision-reliant big fruit bats and the latter being the small bats that use echolocation.

However, such categorization has been outdated over the past several decades. This is due to the fact that previous genetic analysis showed that some bats close to the fruit-eating bats were able to echolocate.

As a result, researchers proposed a new classification for bats, leading to the coinage of Yinpterochiroptera and Yangochiroptera, and these terms have been used ever since.

Patterson advocated the 'use of genetic analysis, saying that it is the most efficient method to determine the evolutionary history of bats.' To determine the recent findings, the researchers CT scanned 31 bat skulls in New York to understand why some bats can echolocate.

The researchers found that there are 39 different species from 19 of the 21 known bat families. The researchers observed most of the bat skulls showed a tiny organ in the inner ear was responsible for bats' capabilities to hear.

Furthermore, the CT scans made by the researchers show that there are huge differences in these tiny structures and these differences may hold to key in understanding that some bats echolocate while other bats do not.

Echolocation Links to Evolutionary Biology

By classic definition, echolocation is the active use of sonar by means of echoing sounds to navigate and measure the distance of one's surroundings, as per the Scientific American.

Bats and dolphins are known to be using sonars to travel from one place to another. These animals also use sonar to detect nearby food and objects. Characterized by high-pitched noises, bats listen to returning echoes to visualize their surroundings even in the dark.

According to Science, although many bats use echolocation, there are some bats that do not have the ability to echolocate. The new study compared the inner ear of the two main groups of bats. The researchers used DNA analysis to find that their ear structure aligns with a split in bat evolution.

In the field of evolutionary biologists, many scientists are still uncertain about how bats developed their sonar. This analogy gave rise to the notion that perhaps an ancient bat developed echolocation and succeeding bats inherited it.