Update 2018: “A new study points to a surprising reason for the varied shape of bird eggs.”

Guillemots are sea birds that reside in crowded colonies on rocky cliff sides. When they breed, they produce one conical egg which incubates for around 30 days on the precarious cliffside… but guillemots don’t make nests.

Without a nest on those densely packed cliff sides, it’s likely that a rounded bird egg would roll right off. But an extra pointy Guillemot egg has two fascinating examples of evolution [see the update below] built into how they look… and how they roll. Steve Mould explains their color and shape in the vid above: The egg that saves its own life.

Bonus fact: Guillemot eggs are also water repellant and self cleaning. Bonus visual: This gif of the egg’s tight spin, via the BBC.