While it is not the absolute noisiest animal, the minuscule male water boatman can reach 99.2 decibels by rubbing his penis against his abdomen to attract new mates.
The volume has been likened to a full orchestra playing, while Maria Sharapova's grunts at this year's Wimbledon Ladies' Singles final on Saturday reached 101 decibels.
However, the sound the water boatman produces usually originates underwater, and a large percentage of the noise is lost in the process.
Lead researcher Dr James Windmill said: "Even though 99% of sound is lost when transferring from water to air, the song is so loud that a person walking along the bank can actually hear these tiny creatures singing from the bottom of the river.
"We were very surprised. We first thought that the sound was coming from larger aquatic species... If you scale the sound level they produce against their body size, they are without doubt the loudest animals on Earth."
Other loud animals include the blue whale (188 decibels) and the elephant (117 decibels). The Alpheidae, also known as the pistol shrimp, can hit up to 218 decibels by snapping its claws together but is 3-5cm in size compared to the water boatman's 2mm body.
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Meanwhile, the volume of a conversation between two people is around 60 decibels.
The water boatman is a plant-eating insect that resides in ponds and streams, but is known to sometimes feed on small animals like tadpoles.
Watch a montage of Maria Sharapova's grunting at this year's Wimbledon below: