Were you aware that researchers have yet to discover a vertebrate species that is deaf? That is unlike a substantial variety of amphibians, fishes, reptiles and mammals that are blind. However, hearing doesn’t specifically call for ears. Only vertebrate animals have ears, whereas invertebrates utilize other types of sense organs in order to perceive the vibrations we all 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. In some species, tiny hairs take the place of ears; in spiders and cockroaches these hairs are on the legs, while in caterpillars they are along the surface of its body. One species known for its acute hearing is the elephant. Elephants have large ears, but they can also hear through their feet. This form of hearing is so acute that elephants can detect the sound of thunderstorms or the low-frequency call of other elephants coming from many kilometers 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. Dolphins have external eardrums on the outsides of their bodies that are so sensitive that they have the best sense of hearing among animals, and are able to hear 14 times better than humans.
Many animals not only hear better than we do, they hear more sounds, easily detecting sounds in frequency ranges far below or above the frequencies that we humans can hear. Cats are recognized as having the most acute hearing among domesticated animals. They can hear sounds at lower and higher frequencies than humans can. A normal human range is 64 to 23,000 HZ. A normal cat range is 45 to 64,000 HZ. Owls also have phenomenal hearing, both in terms of acuity and reaction time; they can detect the exact location of a scurrying mouse in less than 0.01 seconds.
Echolocation is an extension of hearing often considered it own sense since it functions like sonar. Bats and dolphins emit small click or chirps which bounce off of surrounding objects and return to them. They are essentially using sound waves as a tool to “see” their surroundings. Using echolocation, bats and dolphins can determine a great deal about objects they can’t even see, including the objects’ size, location, and even their physical nature. Dolphins can use echolocation to detect objects the size of a small coin over 70 meters away. A bat can detect an insect 30 feet away in complete darkness.
Looking at the animal world is a great reminder of how vitally important hearing is.