Large mammals 'all urinate for same duration'

A 2014 study by engineers and biologists in the US concluded that all mammals weighing more than 3kg take about the same length of time to urinate.

The researchers, from the Georgia Institute of Technology, how now been awarded one of the 2015 Ig Nobel prizes for their work.

They recorded high-speed video of various animals urinating and modelled the fluid dynamics involved.

As the size of the animals increased, so did the rate of flow - producing a consistent urination duration which averaged 21 seconds, although it could fluctuate by up to 13 seconds.

This "scale law" did not apply to small animals, such as rats, which can urinate in a fraction of a second.

Footage courtesy of Georgia Tech / PNAS