Animals eject fluids for waste elimination, communication, and defense from predators. These diverse systems all rely on the fundamental principles of fluid mechanics, which we use to predict urination duration across a wide range of mammals. […]

Using high-speed videography and flow-rate measurement obtained at Zoo Atlanta, we discover that all mammals above 3 kg in weight empty their bladders over nearly constant duration of 21 s. […]

Smaller mammals are challenged during urination by high viscous and capillary forces that limit their urine to single drops.

{ PNAS | Continue reading }

collage { imp kerr }

animals, science | September 9th, 2015