Why do robins have red breasts? © Getty Images

Why do robins have red breasts?

A robin’s red breast may look beautiful to us, but to other robins it’s a mark of how hard he is...

The robin’s distinctive red breast is a beautiful sight as it’s seen against a backdrop of fresh snow. It’s actually a tool in their ongoing campaign to gain or retain territory, according to research from the University of Cambridge. For each year that passes, a male’s red breast gets a little larger.


Robins do not typically die of old age, so every year a robin survives is a credit to its survival skills. Following this logic, an older robin with a large red breast is a real threat, as his survival skills must be very well honed. Such a robin could therefore use his breast to attract mates, or to intimidate younger birds in battles over territory.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.