With a Helping Hand From Tequila Makers, a Bat Comes Back From the Brink

A nectar-loving bat from the southwestern United States and Mexico whose population was tanking has made a remarkable comeback nearly 30 years in the making, and some of the credit goes to an unusual source: tequila producers.

Once endangered and down to fewer than 1,000 bats in 1988, the lesser long-nosed bat is now some 200,000 strong, according to the U.S. Fish and Wildlife Service (FWS).

The agency now thinks the bat, whose range runs from southern Mexico up to southern New Mexico and Arizona, no longer needs to be protected under the U.S. Endangered Species Act and has proposed taking it off that list of struggling animals.

How did the down-and-almost-out bat finally bounce back? With help from multiple sources north and south of the U.S. border. Across decades, citizen-scientists in Arizona kept watch on the animals and provided valuable information on the timing of their migrations, while U.S. federal agencies protected the bats' roosts and hunting areas, most of which were on protected lands.

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Meanwhile, tequila producers in Mexico have given a boost to the bats, after changing the way they harvest the key ingredient in their popular spirit, the blue agave (Agave tequilana).

The blue agave plant spends its life building up sugar and gearing up to blossom, just one time, creating giant stalks – clear-as-day invitations for top pollinators like the lesser long-nosed bat. In turn, the bat dines on the nectar and then pollinates other blue agave in its travels. The agave, for its part, dies after flowering.

The trouble was, tequila producers were harvesting the blue agave just before it flowered, when sugar levels were at their best. For new plants, they used the clones that sprout at the agave's base.

Because the agave plants never bloomed, they never became food for the nectar-hungry bat. The agave are part of a "nectar corridor" the bats use when migrating from southern Mexico to northern Mexico and the U.S. Southwest. The blooming times of agave, saguaro and giant cacti keep the bats supplied with nectar continuously throughout migration.

Over time, bat researchers like Rodrigo Medellín, from the University of New Mexico, worked to convince the producers that it might be best to let the flowering happen instead of replanting from clones.

"[Agave producers] were losing all genetic diversity, and with it all resistance to any disease that would come along," Medellin told the National Resources Defense Council.

Once farmers began to use a portion of their land for flowering blue agave, the hungry bats swooped in, which aided their recovery. "[The fields are] full of food and bats are visiting. It's nothing short of historic,'' Medellín told National Geographic in September 2016. "This is the way things were done six generations ago."

What's more, some savvy producers have even begun marketing "bat-friendly" tequila. As for the bats behind the marketing strategy? They were removed from Mexico's own endangered species list in 2015.

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The FWS delisting proposal is open for comments until March 7 of this year. If the lesser long-nosed bat is delisted, it will still be closely monitored for at least another five years.

"These collaborative efforts have succeeded in recovering this important pollinator and seed disperser, contributing to healthy soils and habitats, and providing sustainable economic benefits for communities," said FWS Arizona Field Supervisor Steve Spangle, in a statement.