Do you remember the scene in the Wizard of Oz when Dorothy and Toto are kidnapped by an army of winged capuchin monkeys? Scary stuff, but why? Because (a) there were lots of them, (b) they were organized, and (c) they had an advantage over other armies: They could fly. More importantly, they could fly and use their hands.

It's this last point that makes the flying monkeys so distinctly fantastic. In the evolution of vertebrates, we simply do not see this phenomenon…ever. If you want to really fly by flapping a limb to get lift and thrust, you have to give up your hands. Bat or bird, no matter how fast or furious, they still can't type a text message. Would you give up your hands in order to fly? “Well, I am a bit attached…” you might say, and I would agree: Stick with the hands and leave off the dreams of soaring. But we do dream, don't we?

Luckily, animals have been spared this philosophical conundrum on the long slog up from the slime. Evolution has decided for us. Slowly, over millions of years, different creatures have developed highly specialized appendages that are modifications of what we chauvinistically call “hands." The bat is a perfect example of a particular survival solution that doesn't work for everybody. Just imagine turning a faucet with those long creepy stick fingers with the flaps of skin between.

Suppose, however, that there was a long lost branch of the evolutionary tree that didn't require its members to give up massage work for a little air time. Suppose, further, that eventually some of them found employment with one Wicked Witch, West. Talk about disruptive technologies! Think about it: the brains of a monkey…the wings of a bat…the hands of a surgeon. You get my point: Advantage. It's a winged advantage, of course, that will allow Oswald to gather more food, find the girlfriend of his dreams, and sire a lot of healthy little winged primates. They, of course, will inherit his surgeon hands and their mom's cute little prehensile tail. Before you know it, their cross-generational refinements will enable them to form armies and sign contracts with megalomaniacs and MGM.

Too good to be true for our contestants in the evolutionary most-likely-to-succeed category? Probably. If the aphorism that nature tends to optimize rather than maximize is true, then I expect we would see compromises at every developmental juncture. Each random path taken would preclude another. “Gee, that long tail sure gets in the way of tight flying turns and, honey, do we really need these big wings if we only visit your mother once a year?” And, “I know junior keeps getting beat up by those big apes at school, but our family has always kept our flying weight down.” The demands of biological survival, as well as the realities of plain physics, mathematical probability and time, seem to level the field in this marvelous spinning dance of natural selection and evolution. 

Are there cases, though, when an animal species got to have it both ways? Could the benefits and costs of flying be reconciled with the benefits and costs of manual dexterity? What forms would be the result?