Law of Urination: All Mammals Take 21 Seconds to Urinate

Posted on October 19, 2013

Patricia Yang and colleagues at Georgia Institute of Technology have discovered the Law of Urination, which states that it takes about 21 seconds for all mammals to urinate. New Scientists reports that the Law of Urination states that "the time a mammal takes to empty a full bladder is proportional to the animal's mass raised to the power of a sixth."

The researchers filmed mammals of all shapes and sizes urinating at Zoo Atlanta and then compared the times. They found that all mammals take about 21 seconds to empty their bladder, regardless of the size or sex of the animals. The scientists found that an elephant's large bladder empties in the same amount of time as mammals with smaller bladder. This is because the elephant's urine is able to reach higher speeds as it is released thanks to a gravitational boost due to its long uretha.

Here is a video showing different mammals urinating. Take a look: