they hear by their ears duhhh

they were interested in them

PCH=Can use echoes to fly in the dark

more commonly known as Echolocation

Bats are not birds. Bats are flying mammals. Some birds have a rudimentary echolocation capacity. These birds are the oilbirds of South America, and the cave swiftlets of Asia.

The Oilbird, or Steatornithidae, is the worlds only nocturnal fruit eating bird. It uses echolocation to find it's fruit during the day. At night, it's uses its' large, light sensitive eyes to search for food. It's echolocation use a clicking sound at an audible frequency of about 7,000 cycles per second. Unlike a bats cry, which is supersonic.