Animals, such as bats, dolphins, rats, whales and oil birds, use ultrasound to navigate or communicate. Bats, dolphins and some toothed whales used echolation, an ultrasound technique that uses echoes to identify and locate objects. Echolation allows bats to navigate through dark caves and find insects for food.
Dolphins and whales emit a rapid series of underwater clicks in ultrasonic frequencies to locate their prey and navigate through water. Male mice and rats use ultrasonic vocalizations as a courtship song to attract female mates. Many nocturnal insects, including moths, grasshoppers, praying mantis, beetles and lacewings, have sharp ultrasonic hearing, which helps them escape predators. While oil birds use ultrasound to fly safely and hunt at night, they use lower echolation frequencies compared to bats and other nocturnal insects.