It’s a pee coup: scientists find most animals take 21 seconds to urinate

Headed to the bathroom? If you think you might have to "pee like a racehorse," join the club - so does every other mammal.

US scientists who watched dozens of different mammals from rats to elephants relieve themselves found that most of them seem to urinate in the same time frame: around 21 seconds.

The findings, released by the Proceedings of the National Academy of Sciences, illuminate the fluid dynamics of urination.

David Hu, a mechanical engineer at the Georgia Institute of Technology and the study's co-author, said he got the idea for the experiment while changing diapers a couple years back.

"I was thinking, 'How could anything be worse right now?'" Hu said. "I thought, 'Well, maybe if I was changing an elephant's diaper it would really bad.'"

The researchers headed over to Zoo Atlanta to watch the animals do their business. They watched videos and compared the size of each species' bladder and urethra. While some larger animals had capacious bladders (an elephant can fill a kitchen rubbish bin), they all - cats goats and elephants, seem to empty in the same time: 21 seconds.