You've seen one bat, but you most definitely haven't seen them all. That's because after rodents, bats make up the second-largest order of mammals. There are over 900 different species fluttering around, from a bumblebee-sized "hog-nosed" bat to gentle giants with wingspans of 5 feet (1.5 meters) or longer.
Most bats eat insects, often in copious amounts. Then you've got your big game hunters: Bats who've evolved strong enough jaw muscles that they can kill off vertebrate prey, such as fish, lizards or birds.
And of course, the blood-drinking vampire bats from Central and South America need no introduction.
But not all bats are carnivores (or vampiric). About 300 species eat fruits and other plant products to survive, which works out great for the rest of us because those flying creatures really help the environment.
What Are Fruit Bats?
One of the most important families of bats is the Pteropodidae. Also known as the "Old World fruit bats," they hang out in tropical and subtropical parts of Africa, Eurasia, Australia and many Pacific Islands.
Remember the "gentle giants" we mentioned above? Those would be the flying foxes, enormous pteropodids who represent the largest bats alive today.
A species called the giant golden-crowned flying fox can weigh 2.5 pounds (1.13 kilograms). You may be relieved to hear that it's a fruit-eater ("frugivore") with a taste for figs, which is hardly unusual.
"Pteropodids eat primarily fruit and nectar," says biologist Liam McGuire, assistant professor at Texas Tech University in an email. "For example, nectar from the flowers of eucalypt trees is a very important food source for several species of flying foxes in Australia. But Pteropodid [diets] can also include other plants (pollen, leaves) and sometimes insects."
You might think the name "Old World fruit bats" implies the existence of "New World fruit bats." And indeed, the Americas have no shortage of winged fruit fanciers.
The Phyllostomidae is another large bat family, one that's distributed across the neotropics of North, South and Central America, plus the Caribbean. While many species are committed insect-hunters, dozens of these animals incorporate plant matter into their diets.
Depending on the bat in question, fruits, nectars, pollen or seeds may be fair game.
Forestry and Tequila
"Frugivorous bats in both the Old World and the New World tropics eat a variety of fruits that tend to be scented, relatively large, green to yellow in color, and exposed away from branches and leaves," Norberto Giannini, mammologist and research associate at the American Museum of Natural History, says via email.
The Old World pteropodids alone feed on more than 1,000 different plant species. Most of these (71 percent) grow fruits the bats like to consume. Other plants may attract pteropodid visitors because of their flowers, leaves, nectars and sap. (Shoots and tree bark are fair game as well.)
Usually, the relationship has mutual benefits.
Seeds swallowed by fruit bats get released elsewhere when the animals poop. According to a 1999 study, tropical bats in some parts of Chiapas, Mexico, distribute more seeds in this manner than fruit-eating birds do.
After a forested place is devastated by wildfires, droughts or human activities, fruit bats help it bounce back.
Research suggests that a colony of 152,000 African straw-colored fruit bats can distribute more than 300,000 seeds in one night! This could be enough to get the reforestation process started across 1,976 acres (or 800 hectares) of land.
Flower and nectar-eaters do their part as well.
Bats are pollinators for upward of 530 types of plants, such as balsa trees, bananas and assorted cactuses. Then we have agave, a key ingredient in tequila. Migratory Leptonycteris bats eat the nectar from their flowers. In the process, the mammals spread agave pollen around, cross-fertilizing the plants as they go.
Sounding Things Out
Echolocation is a sound-based navigating strategy. The process starts when an animal releases high-frequency sound waves through the nose or mouth. By carefully listening for an echo, the sender can decipher a lot about its surroundings.
That's how some predatory bats track down moths and mosquitoes in pitch-black darkness.
Unlike insects, a piece of fruit can't fly away. Regardless, Giannini tells us "[all] New World frugivorous bats use echolocation."
"This type is called 'sophisticated laryngeal echolocation' and it is essentially a laryngeal call emitted through the nostrils and modulated using a nose leaf," he adds. (For the record, nose leaves are weird structures found around the nasal openings of many bat species.)
Over in the Old World, most fruit bats don't echolocate — with a few interesting exceptions.
"Among the Pteropodidae, there are bats in the genus Rousettus that echolocate by clicking their tongues," McGuire explains. "This mode of echolocation has often been considered primitive, but studies have shown that their tongue click echolocation is quite sophisticated."
So much for the old myth that bats are blind.