The ability to produce loud sounds is a powerful biological tool, used by animals to communicate across vast distances, defend territory, warn of threats, and attract mates. The title of “loudest animal” is complicated because the environment—whether air or water—fundamentally changes how sound travels and how it must be measured. Determining the loudest creature requires understanding the physics of sound propagation and the specialized organs animals have evolved to weaponize noise.
How Scientists Measure Animal Loudness
Sound intensity is quantified using the decibel (dB) scale, which is logarithmic, meaning a small increase in the number represents a massive increase in actual sound energy. For instance, a sound that is 10 dB louder than another is ten times more intense. Scientists define the sound pressure level (SPL) by measuring the pressure of the sound wave at a specific distance from the source, typically one meter, which provides a standard for comparison.
Measuring sound in air versus in water requires different reference pressures, which is the main reason underwater readings are numerically much higher. Sound travels over four times faster in water, a dense medium that allows acoustic energy to propagate with less loss over greater distances. Researchers use specialized underwater microphones called hydrophones to record aquatic sounds, often focusing on the peak intensity of a transient sound burst rather than a sustained volume. This distinction between a short, powerful click and a long, drawn-out call is important when comparing record holders across different environments.
The Absolute Loudest: Marine Mammals
The undisputed champion for absolute volume is the sperm whale (Physeter macrocephalus), a massive toothed whale whose vocalizations dwarf all other known biological sounds. These animals produce intense, broadband clicks primarily for echolocation, a form of biological sonar used to navigate and hunt in the deep, dark ocean. A single click from a sperm whale can reach an astonishing 230 to 236 decibels (dB re 1 µPa at 1m).
This extreme volume is generated by a complex nasal structure that includes a large organ filled with a waxy substance called spermaceti. The whale forces air through its right nasal passage, clapping specialized lips, known as the phonic lips, which creates a click. This sound is then amplified as it travels through the spermaceti organ and is directed into the water. The purpose of these clicks is believed to be powerful enough to stun or disorient their primary prey, giant squid, at close range.
Other large marine mammals also rank highly. The blue whale (Balaenoptera musculus), the largest animal on Earth, produces low-frequency groans that can reach up to 188 decibels. These powerful, sustained calls are used for long-distance communication, traveling across entire ocean basins to connect individuals separated by hundreds of miles.
Runners-Up: Loudness on Land and Small-Scale Records
The loudest terrestrial animal is the howler monkey (Alouatta genus), whose booming calls can reach up to 140 decibels. These primates are capable of such extreme volume due to a specialized, enlarged hyoid bone in their throat that acts as a resonating chamber. Their signature howls are used to advertise territory and can be heard over distances of three miles through dense rainforest.
Even smaller creatures produce sounds of surprising intensity. The tiny pistol shrimp (Alpheidae family) generates a cavitation bubble by rapidly snapping its large claw, creating a shockwave that produces a peak sound pressure of over 200 decibels. This incredibly short, sharp burst of sound is loud enough to stun small fish, which the shrimp then consumes. Among insects, the African cicada (Brevisana brevis) is the loudest, using a ribbed, drum-like organ called a tymbal to produce its mating call, which can reach nearly 107 decibels in air. The water boatman (Micronecta scholtzi), a tiny aquatic insect only two millimeters long, is the loudest animal relative to its body size, producing sounds of up to 105 decibels by rubbing its reproductive organ against its abdomen.