Welcome To Mexico, our latest World Tour location!

Welcome to Mexico! After our exciting hiatus for our British Science Week classifications target (which you helped us to hit comfortably), we’re now back on the road for the next stop on the Bat Detective World Tour. This time we’ve headed south, from our previous location in New York to tropical Mexico. Today we’ve uploaded a new set of data collected in 2008 during audio surveys in several locations on the Yucatán Peninsula, so head across to the Bat Detective site now to begin listening and classifying bat calls.

These data were recorded by a team that included Bat Detective’s founder Prof. Kate Jones, and include surveys around the city of Merida, the capital of Yucatán, as well as the Mayan historical sites Edzná and Calakmul, both of which are located in the jungle and are areas of special archaeological as well as biological interest.

Mexico is a remarkable country in which to search for bats. It has among the highest bat species diversity found anywhere in the world, as well as some of the world’s most unusual, beautiful and bizarre bat species. Some of our favourites are the spectral bat (Vampyrum spectrum), the largest carnivorous bat in the world; the fish-eating bat Myotis vivesi, which hunts by using its exceptionally large feet to snatch marine fish and crustaceans from the sea; and the banana bat (Musonycteris harrisoni), whose extremely long snout and tongue are ideal adaptations for feeding on nectar from tropical flowers – and lend it its alternative name of trumpet-nosed bat. Other Mexican nectar-eating bats are famous as important pollinators of agave plants – vital for making tequila.

Locations in Mexico, where Bat Detective audio data were collected

Another of the country’s best-known bats is the Mexican free-tailed bat (pictured below) which is widespread throughout the Americas and famed for roosting in colossal cave colonies of up to several million individuals. Because of its abundance and visibility, it is fairly well studied; for example one 2015 study, published in the journal Science, found that this species has the remarkable ability to produce interference vocalisations to ‘jam’ rival bats’ echolocation sonar, potentially enabling individuals to improve their own hunting success.

In southern Mexico, as in other tropical regions of the world, bats are even harder to survey than in temperate regions – tropical forests are noisy places, filled with inhabitants occupying their own sonic niches and working to be heard above and around each other. Developing automated bat detector softwares to pick out bat calls from this dense acoustic hubbub, and to then identify those calls to the level of species or species group, requires a lot of labelled input data to train our algorithms.

But it’s worth the exploration, since many of the calls you’ll encounter in tropical Mexico are quite unlike our earlier data from temperate regions such as Europe and New York. So if you’re unsure, use the guide underneath the main classify window to help you figure out what sounds you’re hearing. And as ever, if you have any challenges working out whether a call is a bat or not, just click through to discuss it on the Talk section of the site with us and other citizen scientists. These are some of our favourite recordings to be uploaded to Bat Detective, and we hope you’ll enjoy listening and classifying them too.

Mexican free-tailed bats (photo via Wikimedia Commons)

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