Animals are a noisy bunch. They babble and they bleat, and they chirp and croak and coo. And it's no wonder why, since sound is one of the main mediums through which animals can communicate.
Studies suggest that there are around 10,000 species of birds and around 6,000 species of mammals that possess the ability to produce sounds, not to mention the sound-makers in the reptilian and amphibian taxa, among others. For these animals, sounds are the trick to survival. They allow their makers to find food, attract partners, avoid predators, and stake their claims on their territories. But which of the world's animals are the loudest?
Read More: Can Animals Learn Language Like Humans Do?
What Makes a Sound Loud?
To answer that question, it is important to understand what determines the loudness of a sound.
When the sound-producing structures of an animal start to vibrate, whether that animal is a chirping cheetah, a buzzing bee, or a singing sparrow, the molecules of air or water that surround that animal collide into one another in a continual chain. The outcome is a ripple of vibrations that surges through the air or water or whatever medium that surrounds the animal until the vibrations ultimately slow to a stop.
How Do Sound Waves Work?
That wave of vibrations is a sound wave, and the way that that sound wave, well, sounds, is determined by a few factors, including the medium through which it travels and the speed and strength of its initial vibration. While the speed of its initial vibration affects the pitch of the sound wave, the strength of its initial vibration affects its intensity.
Put simply, the stronger the vibration, the more intense the sound. And a number of animals are made for making incredibly intense, or loud, sounds.
Read More: Animals Share Human-like Hallmarks of Speech
What Are Some of the Loudest Animals in the World?
A few years ago, a team of researchers compiled a list of what they considered to be the loudest animals in the world. The team included researchers from the Sound Communication and Behavior Group at the University of Southern Denmark in Odense, which specializes in the comparative analysis of sounds from an assortment of different sound-makers, including birds, bats, and whales.
Standardizing and comparing the measurements of these animal's loudest sounds, the team found that the noisiest animals tend to belong to the mammalian taxon, whether they spend the majority of their time in the air or the water. But there were outliers. Here are seven of the animals that the researchers identified in their paper, published in Frontiers in Ecology and Evolution in May 2021, along with their listed decibel limits.
1. How Loud Is a Sperm Whale?
The shrill sounds of the sperm whale are downright dangerous. Since the 2000s, a whole slew of studies has shown that these animals are capable of creating sounds at a stunning 240 decibels or so, surpassing the sound of a jet engine at takeoff and tossing the whale to the top of the loud animal list.
Sperm whales send out clicks and creaks, which bounce off of prey, allowing the whales to detect their dinner at a distance. With only a couple of these calls, a sperm whale can scope out schools of squid from almost 800 feet away. Recent research suggests that these animals also use unique streams of clicks, called codas, to communicate. In 2022, it was suggested these codas signify a whale's connection to a specific social community.
Read More: Sperm Whales Have the Biggest Brains, but How Smart Are They?
2. How Loud Is a Blue Whale?
It might make sense to assume that the world's largest animals are also the world's loudest. And research reveals the truth of that assumption, announcing that the blue whale — the biggest animal in the world at approximately 330,000 pounds — releases resounding, rumbling calls at almost 200 decibels.
Whether pulses, grunts, or groans, a blue whale's booming calls can connect creatures as many as 1,000 miles away. But that's only possible with the correct ocean conditions, when other sounds aren’t around to drown out blue whale bellows. In fact, researchers recently found these whales are lowering the frequency of their vocalizations, forcing their calls stand out from rest of the ocean's chatter, according to one top theory from 2017.
Read More: Blue Whales Chase the Wind to Hunt Tiny Prey
3. How Loud Is a Snapping Shrimp?
Scampering through the ocean’s tropical and temperate reefs, snapping shrimp are also a sonic amazement, armed with two dramatically dissimilar claws, one small and one not so much. The shrimp’s no-so-small claw is absolutely massive in comparison to its body — with a 2-inch shrimp typically sporting a 1-inch snapper — and makes a sharp, almost 185-decibel sound whenever it is slammed shut.
When an adult snapping shrimp's claw closes, it sends a stunning shock wave through the water that incapacitates any prey animals as they swim or scrabble past. The sound of the shock is likened to a gunshot, though it is actually around 15 to 35 decibels louder than the average bang of a bullet. A 2022 study on the snapping shrimp's powerful pincer suggests that it is one of the fastest moving animal appendages in the ocean.
Read More: The Most Fearsome Ocean Predator Is This Superhero Shrimp
4. How Loud Is a White Bellbird?
The white bellbird may not look like much, but it is actually world’s loudest bird. In 2019, researchers in the Amazon rainforest studied the songs of male bellbirds as they searched for female mates. They found that, from time to time, the serenading songbirds surpassed a volume of around 125 decibels.
The song itself is booming, comparable to the clang of a chorus of pile drivers, according to the researchers who recorded it. But while white bellbirds tend to sing louder than other birds, they don't tend to sing longer than other birds. In fact, the birds' loudest songs are also their shortest, the 2019 study suggests, likely thanks to limitations in their airflow.
Read More: Scientists in the Amazon Have Recorded the World’s Loudest Bird. It Hits a Painful 125 Decibels
5. How Loud Is an African Elephant?
Have a listen to a heard of happy elephants, and you'll certainly think that they're loud, with their frolicking feet and their trumpeting trunks. But those aren't even the loudest sounds that are associated with the big, tusked beasts. In the 1980s, researchers revealed that the African bush elephant makes resounding, rumbling calls at around 120 decibels, that aren't audible to human hearers, no matter how hard we try.
These calls carry over distances of several miles and enable elephants to contact each other despite distance. Surprisingly, the frequency of these calls can drop below the audible range for humans. In fact, studies from the Elephant Listening Project suggests that humans are only capable of hearing approximately 40 percent of the different calls that these elephants produce.
Read More: Can Elephants Learn By Observing and Imitating Others?
6. How Loud Is a Bulldog Bat?
In spite of its smushed, flattened face, the bulldog bat is one of the world's smoothest talkers. Or, at least one of the loudest. Studies show that these bats — native to the trees, shrubs, and streams of North and South America — belt out 120-decibel ultrasonic sounds as they navigate through the night sky.
The bounce-back of the bat's high-pitched peeps help them find flying and swimming food, including insects, scorpions, and shrimp, and avoid air collisions with other hungry animals on the hunt. Recently, researchers have collected recordings of these calls, and thousands of recordings of other types of bat calls, in massive audio archives. An analysis from 2017 says that these archives will assist researchers with identifying bats in the field.
Read More: Protecting the Coolest Types of Bats in North America
7. How Loud Is an American Alligator?
Though they aren't famous for their chatter, alligators are terribly talkative. They chirp to their mothers as hatchlings, and they transition to hisses, growls, and grumbles as they become bigger. But they're the loudest reptiles around thanks to their loud, low-frequency bellows, which blare through their beloved swamps and streams at around 105 decibels.
Adult alligators, both male and female, bellow throughout the year, though they bellow much more frequently between May and June. That's because their bellows play a pivotal part in their mating process, signaling the size of their bodies to potential partners. The deeper the bellow, the bigger the body, according to an analysis of American alligators from 2017.
Read More: Yes, Animals Create Culture and Pass It Along for Survival
Measuring the Sounds of the Loudest Animals
Naturally, whether any of the loudest animals actually sound loud to a human depends on a few factors. For instance, it depends on the distance at which an animal is heard, with an animal a meter away seeming a lot louder than an animal a mile away. It also depends on the frequency of an animal's sounds. A loud sound in a frequency that humans aren't able to hear is nothing to a human but deafening to an animal that's actually able to detect it.
"A major challenge in bioacoustics is to measure sound in a meaningful way — to reflect what animals can hear, rather than what humans can hear," states a study in Frontiers in Veterinary Science from 2022.
By assessing an animal's decibel output, without regard to their frequency output, the 2021 paper from Frontiers in Ecology and Evolution made sure to study the intensity of sounds from the perspective of the animals that produce them, not only from the perspective of humans.
And by assessing the source levels of the animals, defined as the intensity of a sound at a distance of a single meter from the source, they made sure that their sounds were all measured in the same way. The result is an assembly of animals that are skilled at making sound, and a whole, whole lot of it.
Read More: Will Artificial Intelligence Help Us Talk to Animals?
