A cadaver floats when bacteria in the body produces enough gas to float it to the surface. When the water gets warm enough, the formation of gas within the body occurs more rapidly, making it expand and float like a balloon.

Why do dead bodies float on water?

A body floats in water when its weight is less than that of an equal volume of water. ... Bodies whose densities are more than that of water sink in water. The density of the human body is less than that of the water. Therefore, when a human dead body falls in water, it floats for a few seconds in it.

How long can a dead body float in water?

On the open ocean, however, flies and other insects are largely absent. And if the body is floating in water less than 70 degrees Fahrenheit (21 degrees Celsius) for about three weeks, the tissues turn into a soapy fatty acid known as "grave wax" that halts bacterial growth.