The Jamaican fruit bat (Artibeus jamaicensis) is only eight centimetres long and yet it plays an important role in fighting deforestation. Like many herbivorous bats, it chows down on fruit from a variety of rainforest tree species, then spreads the seeds with remarkable efficiency. At a time when many of the world’s tropical forests are facing clear-cutting and deforestation, these bats are a beacon of hope.
The Jamaican fruit bat has short brown fur, weighs about 50 grams, and has a wing span of up to 30 centimetres. Its most distinctive feature, however, is a noseleaf, a fleshy outgrowth on its face, which looks like a third ear. The noseleaf is used to focus its echolocation calls, concentrating the ultrasonic noises into a narrow beam. Like most fruit bats, the Jamaican fruit bat uses the resulting echoes primarily for navigation.
The Jamaican fruit bat needs finely tuned navigational skills. Every night, it travels up to eight kilometres in search of fruit. When it finds a suitable piece, preferably figs, mangoes, avocadoes or bananas, it carries off the fruit to a feeding roost to devour it. (The Vancouver Aquarium’s 269 Jamaican fruit bats eat a mixture of apples, oranges, cantaloupe, honeydew, bananas, mango, papayas and canned food for primates.)
Fruit bats are picky eaters. They use their strong rear molars to crush fruit, suck out the juices and spit out the pulp and larger seeds. The smaller seeds remain undigested and are pooped in flight just 20 minutes later.
A 20-minute digestion process is impressive in its own right, but it also serves an important ecosystem service. Bats help disperse seeds and spread pollen, acting as keystone species in rainforest ecosystems. Many beloved tree species, like mango, banana, and cashew trees, rely on them for this service.
Bats are also useful ecosystem indicators — the health of bat populations provide clues as to the state of the entire ecosystem. One quarter of all mammal species are bats and they’re found in nearly every ecosystem on earth, including right here in British Columbia. In each habitat, they respond to changes and stressors in the environment quickly.
Bats are especially sensitive to landscape changes and habitat loss because they often live in dense colonies and rely on very specific food sources. When a roost or a food source is lost, it can have a huge impact on bats. The local group BC Bats promotes co-existing with bats; half of the local species are at risk by wind farms, habitat loss and a fungus called white-nose syndrome. Simply building wooden houses in areas where bats are being excluded can have a huge impact. A related group, the Kootenay Community Bat Project, successfully installed a roost with 800 resident bats!
In the tropics, where half of the total forest cover has been cleared at least once, bats are losing critical habitat. Central America, where the Jamaican fruit bat makes its home, loses more than one percent of its forest every year to logging, urbanization and agriculture. As forests are carved up into smaller and smaller patches, the habitat fragments. Life living at the fringe tends to struggle and the overall health of the ecosystem declines. Less mobile species, such as trees, don’t have the luxury to move.
The heroes here are the fruit bats. These highly mobile animals travel long distances while foraging, dispersing seed, pollinating trees and linking together fragmented forests.