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An interesting observation that shows just how essential the ability to hear is to living species on the earth is that while researchers have discovered many types of amphibians, reptiles, mammals, and fishes who were blind, they have been unable to locate any species that is naturally deaf. That said, hearing does not specifically require ears. Only vertebrate animals have ears, while invertebrate animals use various other sense organs to perceive the vibrations we know as sound waves.

Insects have tiny tympanal organs that can provide them with far more acute hearing than humans; for example, the female cricket fly can pinpoint the exact location of the cricket it parasitizes just by hearing its song. Spiders and cockroaches have tiny hairs on their legs that they use to pick up sounds, and caterpillars have similar sound-receiving hairs on their bodies. Some animals have two ways of processing sound vibrations. For example, an elephant has extremely large ears, but it also takes in sound information via its feet. Elephant feet are sensitive to the very low frequency calls of other elephants and also the rumble of thunder many miles away.

Fish are interesting too. Fish don’t have ears, but are able to perceive sounds underwater using lateral lines that run horizontally along the length of their bodies. A marine mammal, dolphins have no ears, but have eardrums on the outside of their bodies that give them the best sense of hearing among animals, over 14 times better than human hearing.

Not only do many animals have better quality hearing than humans, they can hear more sounds, detecting frequency ranges that are much higher and lower than the range that humans are capable of hearing. Cats have the most acute hearing among animals we have domesticated as pets; while humans can only hear sounds between 64 and 23,000 Hz, cats can hear sounds between 45 and 64,000 Hz. Birds also have acute hearing, especially owls, whose hearing is not only far better than ours, but more precise in its ability to locate the source of the sound. An owl can pinpoint the exact location of a scurrying mouse in less than 0.01 seconds.

Some species, such as bats and dolphins, extend their hearing abilities by using a form of sonar called echolocation, in which they emit ultrasonic chirps or clicks, and then interpret the sound waves as they return from objects the waves strike. Echolocation is extremely precise. It only takes one chirp to determine an objects’ size and location. Scientists have proven that by using echolocation dolphins can detect objects the size of a small coin from over 70 meters away. Bats can hear insects flying up to 30 feet away, in total darkness, and then catch them in mid-air…now that is hearing.

Looking at the animal world is a great reminder of how vitally important hearing is.