Photograph by Jacques de Speville
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The Mauritius flying fox, a fruit bat endemic to the island of Mauritius, is the target of controversial culls.

Photograph by Jacques de Speville

These endangered bats are being killed by the thousands—here’s why

Scientists are suing the Mauritius government to halt the culling of flying foxes. So far, 50,000 bats have been slaughtered.

Mauritius, a small island nation east of Madagascar, is known for its postcard-perfect beaches, warm hospitality, and cultural diversity. And it’s known for the dodo, the poster child for human-driven extinction. Mauritius has also lost more than 130 other lesser known plants and animals, from giant skinks to burrowing boas, since the island was colonized in 1638.

Now, another unique species, a fruit bat known as the Mauritian flying fox, is being pushed toward extinction. Since 2015, the government has killed more than 50,000 flying foxes, reducing the population of the endangered bats to likely fewer than 30,000.

Officials claim that culls are necessary to protect fruit growers’ crops. “They cause significant damage to the plantations,” Mahen Seeruttun, Mauritius’s minister of agro industry and food security, told the local press last October, just before the most recent cull began. “We are not here to eradicate this species, but we need to make sure the numbers are manageable.”

Preliminary studies indicate that flying foxes account for 11 percent of damage to large mango trees and 9 percent to lychees, the two main types of fruit in question. According to research published in the Journal for Nature Conservation, growers add to the waste by allowing their fruits to overripen. Added to that are the damaging effects of strong winds and other fruit-eating animals and insects.

According to Mauritius’s Food and Agricultural Research and Extension Institute, yields of these fruits have actually decreased since the culls began. Yet bats continue to be blamed and targeted.

“I invite colleagues to come to Mauritius to have a look at what we should not do to nature,” says Vincent Florens, an ecologist at the University of Mauritius. “We’re really going to the bitter end of illogic with the government. Culling of flying foxes has never worked to achieve higher profits—so who is really benefiting from it, if it’s neither fruit planters nor threatened biodiversity?”

Several of Florens’s scientific colleagues are now supporting a lawsuit against the government on grounds of animal welfare violations—specifically, that culling bats with rifles violates section 3.1.a. of Mauritius’s Animal Welfare Act. If they lose the case, Florens and others worry that Mauritius could set a dangerous precedent for targeting endangered species around the world that are deemed nuisances to human activity.

In some ways, Mauritius excels at conservation. It was the first nation to sign and ratify the Convention on Biological Diversity in 1992, and it has helped save endangered species such as the Mauritius kestrel, growing the bird’s population from just four surviving individuals to more than 500 today.

This makes the case of the flying foxes all the more perplexing, says Guillaume Chapron, an ecologist at the Swedish University of Agricultural Sciences, whose work on using legal action to win conservation battles inspired the researchers in Mauritius.

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The flying fox population has plummeted by more than 50 percent since the country began culls four years ago.

“Mauritius is a small story on the planetary level, but here we have a very good illustration of how the world gets destroyed,” Chapron says. “Even for a government that’s an international model for conservation, as soon as wildlife is perceived to impact economic interest, there’s no political will anymore.”

Flying foxes are ecological keystones. As they feast on fruit, they pollinate flowers and scatter seeds, ensuring that forests can thrive. In a 2017 study, Florens and his colleagues found that fruit bats disperse seeds from 53 percent of forest trees in Mauritius—the most significant example of a single bat species’ contribution to a forest that the researchers know of. “Their ecological role is enormous,” Florens says. “All these trees are dependent on this one little endangered bat that the government is massacring.”

According to Florens, the bats’ activity is especially important on Mauritius, where other seed dispersers—including dodos, giant tortoises, broad-billed parrots, and two other flying fox species—have already gone extinct.

WHEN THE TROUBLE BEGAN

Trouble for the bats began in 2002, after Mauritius’s fruit growers—who traditionally sold their lychees and mangos at local markets—began exporting them. As profits increased, so did concerns about losses. For many fruit growers, flying foxes became a culprit for any rotten mangos or chewed up lychees discovered on the ground below a tree.

“Back in the 1970s, bats were only living in the mountains, the forest,” says Hervé Hardy, a retired sugar factory transport manager who is one of the most outspoken advocates for the culls and has published several opinion pieces in the local media in support of them. “Now, we have bats everywhere in the country, and they destroy all the fruits,” he says.

Based on his calculations, Hardy believes that 579,000 fruit bats lived on Mauritius in 2015. (Florens says that figure is biologically impossible because the island isn’t large enough and doesn’t have enough food to sustain that many flying foxes.) Hardy calls for reducing the flying fox population to about 13,000 individuals—the number he estimates lived on the island in the 1970s.

“I’ve seen the evolution of bats myself, that’s why I’m fighting,” Hardy says. “When people say bats have nearly disappeared, I know it’s not true.”

Many fruit growers agree, and their lobbyists began to call for a cull. Politicians—whose success in elections typically depends on winning the rural vote—took heed. As Florens sees it, “The purpose of culling is not to increase the harvest of fruit but the harvest of votes.”

Representatives from Mauritius’ National Parks and Conservation Services did not respond to requests for comment.

When in 2015 the government undertook its first large-scale cull, officials quickly realized that hunting bats near orchards was an ineffective means of meeting the 30,000-plus kill quota set for the cull. “In the orchards, they’d shoot one bat, and 15 would fly away,” Florens says. So they began targeting bats deep in the forest, including in protected areas, where the animals concentrate to roost.

This strategy was “aberrant,” Florens says, because it targeted bats in places where they should be safest and because it removed some of the least problematic individuals from the population—those that likely aren’t eating farmers’ fruit. Flying foxes tend to stick close to home, he says, and ones living in the forest probably aren’t traveling to distant commercial fruit trees to forage. “In short, a bat in the orchard is sure to be eating commercial fruit, but one in the forest is much less likely,” Florens says.

In 2016, the government launched a second cull, of 7,380 individuals “in order to further control the damages caused to fruit trees in selective orchards,” according to Mahen Kumar Seeruttun, a member of Mauritius’s parliament. This contributed to the decision in 2018 by the International Union for Conservation of Nature (IUCN), which sets the conservation status of species, to raise the Mauritian flying fox’s status from vulnerable to endangered.

The IUCN also organized two workshops hosted by Mauritius’s Ministry of Agro Industry and Food Security to promote nonlethal means to mitigate problems between people and bats. “Everyone was quite motivated, and we felt like we were making headway,” says Tigga Kingston, a biologist at Texas Tech University and co-chair of the IUCN’s Old World Bat Specialist Group. Shortly after, however, the government began a third cull of 13,000 flying foxes, which recently concluded.

“None of this is normal,” Kingston says. “This began with an unprecedented action in which a government actively culled a vulnerable species, and then was followed up by an even more unprecedented action.”

Officially, the government has killed 51,318 flying foxes, but Florens and his colleagues believe the number is probably much higher. “The culls took place late in the year, when many mothers were pregnant or had babies,” he says. “You shoot one bat and basically kill two.” Other bats, he adds, were likely injured and died later of their wounds.

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Scientists suing to stop killings of the endangered bats say fruit growers can protect their mangos and lychees effectively by netting their trees.

Mauritius’s flying fox population has fallen by more than 50 percent since the culls began in 2015, according to Florens. The fewer animals that remain, Kingston warns, the more vulnerable the remaining bats will be to natural disasters, disease, competition with nonnative species, and habitat loss. If the killing continues, she says, “the species will be trapped in an extinction vortex where the cull is the beginning.”

After the first two culls, lychee production actually fell by 70 percent, likely, Florens reports in the Journal for Nature Conservation, because of a mix of weather and invasive fruit flies, birds, macaques, and rats. “Unfortunately, all these damages are put on the back of the bat, which makes lobbying more intense,” he says.

Desperate to give the bats a reprieve, a group of researchers decided to sue the government. Fabiola Monty, an environmental scientist in Mauritius with the nonprofit group Human Rights in the Indian Ocean, acted as plaintiff, with Christian Vincenot, a bat ecologist and ecological modeler at Kyoto University, in Japan, advising.

“We tried petitions, demonstrations, publications in Science, and IUCN discussions with the government,” Vincenot says. “Everything we’ve done failed so far, so we decided we needed stronger action.”

Although the bats are recognized as endangered by Mauritius, which follows IUCN guidelines, a loophole in the country’s current legislation excludes them from domestic protection, Florens says. Because of this, Monty filed her suit on grounds of animal welfare violations rather than the breaking of wildlife protection laws. (Monty can’t speak about the case until it concludes, and officials with the Mauritian government have not responded to repeated requests for comment.) The case has been postponed, or appealed, three times, with the next hearing scheduled for May 9.

“THE ONLY THING THAT WORKS”

As litigation continues, Florens and his colleagues continue to push for education and to propose alternatives to killing the bats for farmers who are interested. With a little investment, which can be recouped in a single season, he says, trees can be protected from flying foxes with netting, a strategy used in Australia and Thailand.

“Culling flying foxes has been shown to be useless,” Vincenot adds. “The only thing that really works is protecting trees with nets.”

Proper netting reduced bat damage in Mauritius 16- to 23-fold, according to research published in the journal Oryx. But farmers who have tried this tactic often cut corners, Florens says, leading to the assumption that nets don’t work. “Many growers do a slack job installing the net by throwing it over the tree in direct contact with branches and fruits, allowing birds and bats to eat the fruit through the net from the outside,” he says. Farmers also often leave gaps at the bottom of the net, he continues, allowing animals to enter (and often get trapped inside).

Florens and his colleagues eventually hope to create a bat-friendly certification that will allow consumers at home and abroad to use purchasing power to support fruit growers who sustainably exclude bats from their crops rather than rely on culls. Experts would help environmentally conscious fruit growers install state-of-the-art netting and would then help establish partnerships between growers and local and international marketing firms to raise consumer awareness about the difference such netting makes for threatened biodiversity.

“We hope that farmers who put up nets will make so much money that others who continue to count on the cull will be put out of business,” Florens says. “We want to change the mentality at the grassroots.”

Wildlife Watch is an investigative reporting project between National Geographic Society and National Geographic Partners focusing on wildlife crime and exploitation. Read more Wildlife Watch stories here, and learn more about National Geographic Society’s nonprofit mission at nationalgeographic.org. Send tips, feedback, and story ideas to ngwildlife@natgeo.com.