Do I need to tell you any more? Can't we just let that sentence stand, knowing that it's out there, and go on with our lives? No? Okay. Here's some more detail.
The water boatman is a tiny insect that lives at the bottom of freshwater ponds and slow streams. It's less than half a centimeter long but make a noise of 99.2 decibels. A freight train is about 80 decibels. This makes the water boatman, relative to its size, the loudest creature on earth. Although blue whales are louder, they are massive and use their entire respiratory tract to make noise. The humble water boatman has only its penis.
To make this sound, which alerts females to its presence and amorous mood, the water boatman scrubs its penis along ridges on its abdomen. It does this fast and forcefully enough so that the sound is the equivalent to sitting in the front row of a concert hall while a symphony is being played. There are a lot of water boatmen in the United States and Europe, and the only thing that has kept us landlubbers from being driven mad from the sound is the fact that sound doesn't carry well from water to air. In fact, most sound doesn't carry at all from water to air. An easy ninety-nine percent is lost. And yet people who walk along ponds where water boatmen live can hear them playing away under the water. The sound, which is a scraping chirp, would probably be taken for crickets by most. Anyone reading this article now knows better.
The water boatman's amazing sound has just recently been quantified. The work was done by researchers in Scotland and France, including Doctor James Windmill, who is at pains to convey how impressed he is with the water boatman. The insect is only about 2 millimeters long, and researchers stress that the "area producing the noise" is only about the size of the width of a human hair. Dr. Windmill says, "We really don't know how they make such a loud sound using such a small area," proving, once and for all, that scientists can be both very impressed and very cruel at the same time.