For the last five years, Miller has used the Anabat to study bat populations throughout Belize. So far, he's identified about 80 percent of the 74 known bat species in the country by their voices. Now, acoustically, we find they're everywhere in a healthy forest. It's causing us to reassess the concept of rarity. Certain species are only abundant in relatively unspoiled forest, and tallying these populations helps biologists diagnose forest health.
Bats are particularly sensitive to habitat changes because they bear just one pup each year.
Because of their low reproductive rate, Miller explains, it takes years for threatened bat populations to rebound. That's one reason bats provide a good indicator of habitat quality. Sonic Sight Bats aren't the only animals that use sound to navigate and hunt for food. Other well-known echolocators include dolphins, toothed whales, seals, small mammals like shrews and rats, and some birds. Like bats, these animals emit pulsing sounds, with intervals of silence to listen for returning echoes.