Bats are incredibly diverse animals: They can climb onto other animals to drink their blood, pluck insects from leaves or hover to drink nectar from tropical flowers, all of which require distinctive wing designs.

But why aren't there any flightless bats that behave like ostriches—long-legged creatures that wade along riverbanks for fish like herons—or bats that spend their lives at sea, like the wandering albatross?

Researchers may have just found the answer: Unlike birds, the evolution of bats' wings and legs is tightly coupled, which may have prevented them from filling as many ecological niches as birds.

We initially expected to confirm that bat evolution is similar to that of birds, and that their wings and legs evolve independently of one another. The fact we found the opposite was greatly surprising.