Posted on Categories Discover Magazine
Bats often get a bad rap. They’re known mostly as characters in spooky myths or Halloween stories. But these flying mammals are responsible help keep ecosystems in balance and our food economy humming.
Bats comprise one fifth of all living mammal species and are found everywhere on Earth except the ice-covered poles. They first appeared on Earth over 50 million years ago, long before humans. While many people assume bats are related to rodents because of their size, taxonomic research shows they’re more closely related to horses.
All 1,462 known species of bats are of the order Chiroptera, which means “hand-wing” in Greek. The smallest species, the Bumblebee Bat found in Southeast Asia, measures just 1 to 3 inches and weighs less than one tenth of an ounce, while the largest species, the Giant Golden-Crowned Flying Fox in the Philippines, has a wingspan up to 6 feet.
Like toothed whales, bats use echolocation — sound cues — to navigate and locate prey. Fishing bats, for instance, can detect a minnow’s fin as thin as a strand of human hair poking just a couple millimeters above the water’s surface. The African Heart-Nosed Bat can hear a beetle walking on sand from more than six feet away.
This bat superpower decreases with noise pollution, however. When Pallid Bats are exposed to even low levels of noise, their ability to locate prey declined by half and the time they spent searching for prey nearly tripled, according to research published by The Royal Society in 2021.
North America has 154 bat species alone and has each adapted to occupy a unique niche in the ecosystem. Winifred Frick, chief scientist at Bat Conservation International, says her “all-time favorite bat” is the Pallid Bat that lives in desert habitats throughout the western U.S. and Canada and central Mexico. They have large ears to listen for the scuttle of prey, which includes crickets, cicadas, lizards, rodents — and even scorpions, whose venom doesn’t bother them.
Frick is also enamored of the continent’s smallest bat species, the Canyon Bat, which roosts in cracks and crevices of boulders or rock faces across much of western North America. They fly out each evening around sunset to hunt for bugs. Although most bats have only one pup per year, canyon bats give birth to tiny twins.
Endangered Hawaiian Hoary Bat (Credit: United States Geological Survey)
The Hawaiian Hoary Bat holds the record for the longest trans-oceanic dispersal event for terrestrial mammals. Its ancestor made the 3,600-km voyage from North America to Hawai’i roughly one million years ago. Native Hawaiians call this bat ‘Ōpe’ape’a: pe’a, which refers to the sail shape on outrigger canoes. Ancient Polynesian voyagers used these canoes, and like this bat, crossed the vast Pacific Ocean to settle the world’s most isolated island chain.
North America is also home to the fastest mammal in the world, the Mexican Free-Tailed Bat. It can reach speeds of 100 mph during short bursts of flight. Bracken Cave near San Antonio, Texas is a summer maternity colony for up to 20 million Mexican Free-Tailed Bats, the largest colony of bats on the continent.
Read More: Bat Faces Are Vast and Varied
(Credit: Shutterstock/Natalia Golovina)
Since most bats eat insects — including pests that can damage crops—it behooves humans to help bats thrive. For instance, a single colony of 150 big brown bats gobbles up nearly 1.3 million insects per year. A 2011 study by researchers from the University of Tennessee at Knoxville estimated that it would cost the North American agricultural industry between $3.7 to $53 billion a year if bats disappeared.
In Thailand, researchers estimated that the Wrinkle-Lipped Bat may prevent the loss of almost 2,900 tons of rice per year by eating the white backed plant-hopper, a major rice pest. This natural pest control translates into an annual economic value of $1.2 million, or enough rice meals to feed nearly 26,200 people each year.
Fruit-eating bats in tropical latitudes provide food security, too, along with healthy forests. Studies have shown that bats are better than birds at dispersing fruit seeds— particularly pioneer species like figs that help tropical forests regenerate. Bats are the primary pollinator of durian fruit, considered a delicacy in Southeast Asia. And in Mexico, bats are the main pollinators of agave plants, which means that we can thank bats for tequila.
Bats are also giving insight into ways to boost human health. A protein in the saliva of the common vampire bat called Draculin was developed into a medication that helps prevent strokes by breaking down blood clots. Researches are also studying bats’ immune systems to learn why they tolerate or are immune to certain viruses — including COVID-19 and Ebola —to help humans better cope with these diseases.
Read More: 20 Things You Didn’t Know About … Bats
(Credit: Shutterstock/Volha Werasen)
Unfortunately, nearly half of North America’s bat species are at risk due to habitat loss as well as severe droughts and temperature extremes caused by climate change, according to the first-ever State of the Bats Report released in April 2023.
“Bat experts are really worried because over 50 percent of bats in North America could face serious declines in the next 15 years,” says Frick. Rather than cause for despair, she sees this report as “motivation for action.”
Bat Conservation International and its partners are already using innovative approaches to help bats recover, like building “bug buffets” to help certain species survive white-nose syndrome. This fungal disease introduced from Europe causes skin lesions on some bats during the winter that diminish energy reserves to the point they can starve to death. A study released in March 2023 found that placing ultraviolet near entrances to caves where little brown bats hibernate lured in insects, providing infected bats with three to eight times more food during spring and fall.
“There isn’t going to be a simple solution to this wildlife crisis,” says Frick. “But I’m hopeful because people are working together to protect sites and create the kinds of conditions that benefit bats.”
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