Bats DO eat mosquitoes.

More Info: The only flying mammal, one bat can eat 1,200 mosquitoes in an hour playing an important role in regulating insect populations. [1]

Insectivorous bats, those species that eat insects, comprise 60-70% of all bat species and prey on a variety of insects including mosquitoes, wasps, flies, gnats, crickets, and grasshoppers.  Many times, when a bat seems to be swooping toward a human, they are only chasing the mosquitoes that are trying to feed.

How Do Bats Capture Their Mosquito Prey?

Depending on the size of the prey and the species, bats use a variety of methods to capture their prey.  Most smaller insects, such as mosquitoes, are simply eaten right out of the air.  Bats feed on larger flying insects by swooping down on them, pulling them in with a wing, and dropping them into the interfemoral membrane (also called the uropatagium), which is the flap of skin between the bat's legs used for flight and food captivity.  Larger insects commonly found on the ground such as grasshoppers and beetles are frequently snatched up by the bat's feet.

Bats Are Nocturnal Creatures

Bats sleep during the day and emerge at night to feed.  They generally begin to stir as dusk sets in and will emerge after dark to begin feeding.  They will feed for a few hours and then return to the roost for rest.  Many will reemerge for a second feeding before daybreak.