We don’t usually post pre-prints, but we couldn’t resist this one. A group of physicists from Georgia Tech went to Zoo Atlanta to watch animals urinating. To their surprise, they discovered that regardless of size, most mammals urinate for about the same amount of time (21 seconds), despite large differences in bladder volume, a phenomenon they term the “Law of Urination”. They explain this law using physics, and illustrate their explanation with an amazing video (below) that is absolutely a must-see.