The human hearing range depends on both the loudness and the pitch of the sound produced. Loudness is measured in decibels (dB) while pitch is measured in hertz (Hz). A person with average hearing ability perceive sound frequency from a range of 20- 20,000 Hz. A typical conversation is about 60 dB, but normal hearing begins at 20dB. Zero decibel (0 dB) is near total silence; some people have such sensitive hearing that they can hear 0dB. Some scales range up to negative decibels, and extremely sensitive people can hear sound at -10 dB, 1000 times better than ordinary people. For humans, exposure to 85 dB is dangerous for the ear, 120dB is extremely painful, while 150dB can rupture the eardrums. There are a lot of sounds that human beings cannot hear because they are out of our frequency or pitch range. Humans cannot hear the sound of a dog whistle because the frequency is too high, but dogs can perceive and react to the sound because they have a much wider hearing frequency and pitch range. When the pitch is too low we cannot hear the sound, for example, the roar of a wind turbine is heard as vibration rather than sound although the turbine is actually producing sound. The sperm whale is the loudest animal on the planet with a recorded 230 dB followed by the blue whale with 188 decibels. The following are the loudest land animals.
15. American Alligator - 90 decibels
The American alligator produces low-frequency but high pitched sounds known as “bellows”. The sounds of the alligator can reach 90 decibels and are produced when warding off invaders or contesting for mates. Alligators make the sound by exhaling either below or above the water to communicate their sizes to the potential mate or challenger.
14. Coqui Frog - 100 decibels
The coqui frog is a small but extremely loud amphibian with sounds of up to 100 dB. It is native to Puerto Rico, but it has invaded parts of California and Hawaii. In 2014, coqui frogs invaded residential areas of Hawaii and caused sleepless nights among the people. In California residents were advised to water their lawns with hot water to kill the eggs of the coqui.
13. Three-wattled Bellbird - 100 decibels
The three-wattled bellbird is native to Central America. The sexes have different physical appearance; males have brown plumage with white heads and throats while females have an olive plumage and yellow underparts. The three-wattled bellbird is a noisy bird that can produce sounds at 100 decibels. The males, in particular, are extremely noisy when attracting females.
12. Hyena - 112 decibels
The Hyena is known as a scavenger with a powerful bite force. A pack of spotted hyenas can rival lions and drive them away from their kill. The sound of hyenas is famous because it is associated with laughing. The noises of these animals can reach 112 decibels. Hyenas make the laughing sound when attacked, calling a family member, or when attacking other predators.
11. Hippo - 114 decibels
The hippopotamus is the most dangerous animal in Africa; it kills more people than all wild cats combined. Although they are large-bodied, the hippos can clock speeds of 20 miles per hour. The hippo producers groans and grunts at 114 decibels when threatened or establishing dominance.
10. Lion - 114 decibels
The lion is known to be aggressive and powerful, but it is also the loudest cat. The king of the jungle can produces sounds at 114 decibels. The terrifying roar of a lion can be heard from 5 miles away. Lions also grant and purr as a sign of dominance. They roar to mark their territory, ward of invaders, or when calling their pride.
9. Gray Wolf - 115 decibels
The grey wolf is a nocturnal animal that mostly hunts at night. It is portrayed in films as a dangerous animal with a deafening howl. The grey wolf is indeed loud an can produce sounds of up to 115 decibels that can be heard from several miles away. These wolves live in a pack of between 6 to 15 members. The entire park howls to mark territory or when it encounters another pack.
8. African Elephant - 117 decibels
The African elephant is an extremely intelligent and social animal. It produces different sound to communicate with other elephants. The sound is in the form of rambles, snorts, trumpets, and roars. Each sound signifies a different thing such as a sign of anger or danger. The trumpet of an elephant has been recorded to be as loud as 117 decibels. When an elephant rambles, the sound can travel up to six miles.
7. North American Bullfrog - 119 decibels
The North American bullfrog is native to eastern North America. It is the loudest amphibian and can produce sound of up to 119 decibels. Both females and males make the low-pitched sound but the males crock louder and more frequent to attract the females. During the mating season, the males form a group and engage in a deafening chorus.
6. Green Grocer Cicada - 120 decibels
The Green Grocer Cicada is the loudest in the insect family. It is known to produce sound that can reach 120 decibels, which is painful to the human ear. The cicada produces sound by rapidly vibrating its exoskeleton rapidly. The male is louder than the female and the louder the male, the higher the likelihood to attract females.
5. Northern Elephant Seal - 126 decibels
The northern elephant seal inhabits the eastern Pacific Ocean. This mammal makes loud noises of up to 126 decibels. The sound of the elephant seal is unique, and members of a group are identified using the sound they make. The tone of the sound is also interpreted to mean different things such as a mother calling her calf or warning other seals of impending danger.
4. Moluccan Cockatoo - 129 decibels
The Moluccan Cockatoo is a bird in the family of parrots. It is endemic to eastern Indonesia but kept worldwide as a pet. It is a very noisy bird that is known to produce sound of up to 129 decibels, earning it the title of the loudest bird in the world, although this is shared with the Kakapo . The owners of these birds complain of ear problems due to exposure of loud noises. The sound can be heard from 5 miles away.
3. Kakapo - 132 decibels
The kakapo is a bird that belongs to the parrot family. The Kakapo competes with the Moluccan Cockatoo for the title of the loudest bird on the planet. The kakapo can produce sound of up to 132 decibels and cover a distance of about four miles. The high-pitched sound is produced within the thoracic air cavity. The flightless bird is nocturnal and can live for up to 90 years.
2. Greater Bulldog Bat - 137 decibels
The greater bulldog bat can produce sound of up to 137 decibels. However, the frequency of sound produced by the bat is out of human hearing range and thus requiring the use of technology to hear the sound of the bat. The frequency of the sound slowed down by at least ten times to be audible to humans. When heard from 10 centimeters away, 137 decibel is extremely painful to the human ear, but when moved one meter away the sound reduces to about 20 decibels. Bats use sound to rage obstacles by measuring the time it times the sound produced to echo back.
1. Howler Monkey - 140 decibels
The howler monkey has the loudest sound of all land animals in the world. This amazing monkey inhabits the forest of Central and South America. At peak, the monkey can produce sounds that reach 140 decibels and can be heard from a distance of three miles. The howler monkeys live in a group of between 6 to 15 members. They howl as a means of communication especially when calling their young ones or a dangerous predator is cited.