The speedy bird catches the girl

While the early bird might catch the worm, it’s the quick bird that gets the ladies. That’s the case for rock ptarmigans anyway – a species of bird that lives on the Norwegian archipelago of Svalbard.

Male ptarmigans run more efficiently and up to 50% faster than females and it’s believed that faster males are more successful at breeding than their slower brethren. This is due to their ability to defend larger territories against rivals, suggesting that physiology – not just physical appearance – plays a role in sexual selection.

Read more at University of Manchester