The question of the world’s loudest animal is not simple, as the answer depends on how sound is measured, the environment in which it is produced, and whether the volume is considered in absolute terms or relative to body size. Animal vocalizations and sound production methods are diverse, ranging from the deep, sustained calls of ocean mammals to the rapid snaps of tiny invertebrates. Understanding which creature holds the record requires appreciating the different acoustic strategies animals use to survive and communicate.
Defining Sound Measurement and Context
The standard unit for measuring sound intensity is the decibel (dB), which operates on a logarithmic scale. This means that a sound measuring 100 dB is ten times more intense than a 90 dB sound, and a 120 dB sound is a million times more intense than a 60 dB sound. This logarithmic nature means small numerical differences in decibels represent enormous differences in power when comparing species.
Context is important when interpreting these measurements because sound behaves differently depending on the medium it travels through. Water is far denser than air, allowing sound to travel much faster and with less attenuation over distance. For this reason, the absolute loudest biological sounds are almost exclusively found in the ocean. Scientists must use a standardized reference point, often measured at one meter from the source, to ensure a fair comparison.
The Absolute Loudest—Marine Giants
The reigning champion for the loudest biological sound is the sperm whale (Physeter macrocephalus), an enormous toothed whale. These animals produce rapid, high-intensity clicks that can reach 230 to 236 decibels underwater. This impulse sound, louder than a jet engine at takeoff, is generated by a complex structure in the whale’s head known as the spermaceti organ and phonic lips.
The function of these clicks is two-fold: long-distance communication and echolocation for hunting. The highly directional sound beam allows the whale to locate giant squid in the deep sea. The blue whale (Balaenoptera musculus) is another acoustic powerhouse, producing sustained low-frequency moans that reach up to 188 dB. These low-pitched calls, below the range of human hearing, are used for communication across vast ocean basins, allowing whales to keep in touch over distances of up to 1,000 miles. The difference is noteworthy: the sperm whale’s click is an impulse sound of extreme peak pressure, while the blue whale’s song is a long, sustained tone.
Loudness on Land—The Terrestrial Record Holders
When the environment shifts to air, the maximum volume drops significantly due to the medium’s lower density and higher sound attenuation. Among terrestrial mammals, the howler monkey (Alouatta genus) is considered the loudest, with its distinctive roar audible up to three miles away through dense jungle. This territorial call is produced by a specialized, enlarged hyoid bone and vocal chamber that acts as a powerful resonator.
The howler monkey’s call registers around 90 to 100 decibels when measured at a standard distance. The record for the loudest terrestrial invertebrate belongs to the African cicada (Brevisana brevis). This insect creates a sound of nearly 107 decibels, measured from 50 centimeters. Male cicadas generate this mating call by rapidly vibrating specialized, drum-like membranes called tymbals, located in their abdomen.
The Champions of Relative Volume
While the sperm whale is the absolute volume winner, a more surprising answer emerges when considering relative volume, scaled against body size. In this category, the tiny freshwater insect, the water boatman (Micronecta scholtzi), holds an impressive record. This small creature, measuring just two millimeters in length, produces a courtship song that peaks at 99.2 decibels.
The sound is created through stridulation, where the male rubs a ridge on its genitalia against a ridged part of its abdomen. Its volume, relative to its minuscule body mass, makes it the loudest animal on Earth by this metric. Another contender is the pistol shrimp (Alpheus species), known for its sonic weapon. By rapidly closing its disproportionately large claw, the shrimp creates a high-speed jet of water, forming a cavitation bubble that immediately implodes. The resulting shockwave registers at over 210 decibels at the source, loud enough to stun or kill small prey.