Why are rugby balls oval, not round?

The rugby ball was not always oval shaped. Early rugby balls were made out of inflated pig’s bladders, encased in leather and hand-stitched. The smelly bladders had to be inflated by lung power alone and therefore the balls varied in size – they were more plum-shaped than oval. In 1870 Richard Lindon invented an inflatable rubber bladder and a brass hand pump. Because of the stretchy rubber the shape gradually changed from a sphere to an oval. Over the years, the shape has changed slightly to make the ball more streamlined for passing and easier to hold.

Claudia Velhas, Science Museum