The eastern and western meadowlarks look nearly identical, behave in the same way, and share similar habitats — even overlapping in range in the central plains of North America — yet they are separate species that rarely interbreed. What keeps them apart are the different songs they sing.

Hopkin’s rose nudibranch is a sea slug that lives in the tidepools along North America’s West Coast. It gets its rosy-pink pigment by eating pink bryozoans — tiny, colonial animals that form larger plant-like structures. Despite looking like bubblegum, its frilly pink appearance is thought to deter predators.