In an effort to identify and save rare species, an international team of scientists has compiled the world’s biggest library of bat sounds.

Led by researchers from the University College London (UCL), University of Cambridge, and the Zoological Society of London in the United Kingdom, the team did the study in Mexico, which boasts many of the known bat species on Earth — but also one of the highest bat extinction and habitat loss rates.

They have collected over 4,500 bat calls from over 1,300 individual bats coming from about half of 130 species in the country.

According to lead author and UCL professor Dr. Veronica Zamora-Gutierrez, audio surveys are playing an increasingly important role in monitoring biodiversity issues.

“By tracking the sounds they use to explore their surroundings, we can characterize the bat communities in different regions in the long term and gauge the impact of rapid environmental change,” she explains, highlighting bats’ significant contributions to ecosystems as pollinators, seed dispersal agents, and controllers of insect populations.

The audio library — which can be used for monitoring biodiversity changes and knowing species distributions in the most understudied, far-flung locations — allows bat calls to be automatically identified.

But it wasn’t as easy to do, adds Zamora-Gutierrez, until the team paired machine learning algorithms and voice recognition software with hierarchy data to automatically identify different species, which typically have very similar calls.

Apart from sheltering the most number of bat species worldwide, Mexico also provides a home to the most unusual and bizarre species, including the fish-eating beat, the banana bat feeding on tropical flowers’ nectar, and the biggest carnivorous bat in the world.

Today, many species of bats — which form one-fifth of all terrestrial mammals — have become endangered due to hunting and human development.

The team is currently developing tools to identify bat, using the Bat Detective website.

The findings were published April 14 in the journal Methods in Ecology and Evolution.

In North America, six million bats have already been killed by white-nose syndrome since 2006. This condition is caused by the skin-penetrating fungus Pseudogymnoascus destructans, which eats away at the creature as they hibernate.

Photo: U.S. Fish and Wildlife Service Headquarters | Flickr