These strong-flying bats typically pursue insects in open, uncluttered airspace above the canopy and they can fly to high altitudes. Studies in Africa, Australia, and North America document foraging by molossids at altitudes of several hundred feet (meters) above ground level. Radar shows that Brazilian free-tailed bats fly to altitudes of up to 2 mi (3.2 km) over central Texas, and research has confirmed that large numbers of these bats are actively feeding on insects at altitudes of at least 4,000 ft (1,219 m) above the ground. Molossids detect and pursue insects using relatively low-frequency echolocation calls (typically <30kHz, but <10kHz in some species) that travel long distances in open airspace. Recent studies suggest remarkable diversity in their echolocation calls.
Molossids are known to forage in groups and to exploit patches of insects such as emerging swarms of termites, winged ants, and large migratory populations of moths. They also forage around streetlights that attract concentrations of insects. These bats prey on a great variety of insects. Recent studies of Brazilian free-tailed bats document that their insect prey consists of at least 12 orders and 35 families of insects. Moths (Lepidoptera) and beetles (Coleoptera) provide the bulk of their prey, but all evidence indicates that Brazilian free-tails, in particular, and molossids, in general, are highly opportunistic feeders that exploit a diverse diet of insects.
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