In the dusty expanses of central Mexico's Chihuahuan Desert, hidden among the brown rocks are cold, dark caves.
They are home to thousands of small, furry bats during late spring.
Most are females and have embarked on a 1.609-kilometer journey from southern Mexico to southwestern America, where they will give birth.
They are hungry and fly for hours at night to find enough food.
They flap their wings from plant to plant, collecting nectar and spreading pollen along the way.
Their favorite is the puffy yellow agave flowers, which appear only once in the plant's decades-long life.
These sharp, fleshy leaves have a long history in Mexican culture.
They are used to make syrup, rope, and soap, and their sap is the main ingredient in one of Mexico's most legendary exports - tequila.
But wild agave is in decline, in a study conducted on 168 species, 42 are now endangered or critically endangered.
This means less food for the bats that depend on their flowers, and fewer bats mean fewer agave plants are pollinated.
To break this vicious cycle, conservationists are working with locals to plant thousands of agave plants, helping to feed the bats and protect the future production of Mexican tequila.
One species of bat dependent on agave – the lesser-known long-nosed bat – has experienced an incredible population recovery in recent decades, multiplying from 1.000 individuals in 1988 to a staggering 200.000 today.
But others aren't doing so well.
The Mexican (or greater) long-nosed bat has declined by an estimated 50 percent in the last two decades and is currently endangered.
Another species, the Mexican long-tongued bat, has a near-threatened status.
Biologist Marco Antonio Reyes Guerra is part of Bat Awareness Project at the National Autonomous University of Mexico, which encourages farmers to grow agave, which bats love.
Many of the threats bats face are caused by humans, he explains.
"If something disturbs them in the caves, they will leave them and lose their home," he says.
"People are clearing several areas of dry forest for this purpose, and in that forest are species that bats use as a food source."
These species include agave, as well as other plants that bats feed on.
Scientists from Bat Conservation International (BCI) are determined to turn things around for this endangered species.
The agave restoration initiative involves planting and protecting wild agave in the 'nectar corridor' that bats follow during migration.
“The whole thing started because, once these migratory bats leave central Mexico, they depend heavily on agave,” says Ana Ibarra, a bat biologist and regional director of BCI.
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Wild agave already faces numerous threats.
It is harvested for making alcoholic beverages, grazed by livestock, lost to agriculture, and facing drier conditions due to climate change.
Also, because there are fewer bats, pollination occurs less frequently.
It depends on them like hungry bats depend on agave for food.
"Bats and agave have coevolved over several million years," says Reyes Guerra.
With long tongues and long noses, bats can squeeze into the narrow, cone-shaped flowers of agave to feed and collect pollen on their faces and fur.
"If bats are not in the ecosystem, the agave probably won't produce seeds to reproduce, because it can only reproduce once in its lifetime."
Without any intervention - and threatened by climate change - scientists estimate that endangered bat species will have 75 percent less access to agave nectar by 2050 than they do today.
For conservation efforts to work, the agave must have a chance to grow old enough to bloom - not just for the sake of the bats, but also for its own sake.
Farmers who grow agave for tequila often cut the stem to prevent flowering, which results in a larger 'heart' (or pine tree) for reading.
Instead of reproducing through pollination, these plants produce 'puppies' that are genetic clones of their parent plant.
This reduces the species' genetic diversity, making it less resilient to the dry conditions that come with climate change, as well as to pathogens and pests.
“It’s a big risk for the agave and mezcal industries,” says Reyes Guerra.
Ultimately, to survive as a species, the agave must be pollinated.
“Without bats, tequila and mezcal wouldn’t even exist,” adds Reyes Guerra.
"If people want to continue drinking tequila and mezcal, they have to take care of the bats, they have to take care of conservation."
Since the Agave Restoration Initiative was launched in 2018, the team and local communities have planted more than 180.000 native agave plants and have more than 150.000 growing from seed in nurseries in Texas, Arizona, New Mexico, and throughout Mexico.
The bat-friendly tequila and mezcal project of Reyes Guerra is also working to increase the number of yellow agave buds throughout southwestern Mexico.
Participating farmers allow at least five percent of their agave plants to mature and flower, so that bats passing through can feed on them.
Alcoholic beverages made on the farm are considered 'bat-friendly'.
So far, 300.000 bottles of 'bat-friendly' tequila and mezcal have been produced.
It's not just farmers who are shaping the future for bats and agave.
In Mexico, 53 percent of land is owned by communities, meaning any conservation efforts must involve everyone who lives on that land.
“It was clear from the beginning that we had to work with communities and try to meet the needs of both bats and people,” says Ibarra.
The first step was to teach people that nectar-feeding bats are not harmful.
People often think they are vampire bats, which transmit rabies.
Some even burn caves with bats in them "without knowing if they were really vampire bats," says Ibarra.
"In the past, people hated bats and tried to kill anyone they saw," adds Lisette Lejekin, director of the Sierra La Mojonera Flora and Fauna Protection Area, protected natural areas in Mexico.
She works closely with the Agave Restoration Initiative, as well as with locals to change perceptions about bats.
Today, after the educational program, people are actively protecting the caves.
"They don't let people come in and do anything that would hurt the bats. Almost everyone really loves the bats. They've realized that the bat is very useful," says Lejekin.
Six important nests of long-nosed bats in Mexico have been protected by local communities, and the initiative's educational program has reached more than 1,5 million people.
Reyes Guerra agrees that bat conservation starts with locals.
"You can't do conservation without taking local people into account and consulting with them when you make decisions," he says.
"They sometimes have really valuable information that we, as scientists, don't know."
Reyes Guerra, for example, was recently brought to a tiny cave inhabited by five species of bats.
"That's a really, really rare find," he says.
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The true results of recent conservation efforts, however, will not be felt for several years, because agave takes a long time to grow.
But thanks to both BCI and Bat Awareness Project, people are allowing more agave plants to mature and bloom.
"You can see beds of blooming agaves in areas where there used to be nothing, because people are now leaving flowering stems for bats," says Ibarra.
Ibarra has already noticed an increase in the number of baby bats.
“These improvements are not huge leaps, but they are steady,” she says.
"When you've only seen declines all the time, just having stable numbers is a big victory."
Leykin noticed that where the agave was planted, the landscape began to look greener.
"You can see a lot more fauna, because they have food, they have places to hide."
A bountiful, blooming nectar corridor with agave is still far in the future.
But even then, Reyes Guerra points out that bats will need even more help.
"The problem with just reforesting with agave is that bats feed on several species. So if we just plant agaves to feed the bats, it won't be enough."
Restoring the agave population is just the first step in creating a healthy ecosystem in which more plants and more bats can thrive.
People are a key part of that ecosystem, says Lejekin.
"Taking care of bats here works for both people and the ecosystem. In reality, everything is connected."
And if a life well lived includes tequila – whether as a farm income or an evening drink – then a desert landscape filled with chirping, flying creatures and lush, blooming life benefits everyone.
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