Scientists have long wondered why birds don’t simply flap themselves smack into the emergency room, given the massive forces placed upon their shoulders in order to generate flight.
So scientists at Harvard and Brown have newly investigated the matter, and, if you have at all been thinking what I’ve been thinking, it will come as no surprise that the answer lies primarily in the acrocoracohumeral ligament. Well, duh.
According to a helpful article on Live Science:
The key, they found, is the acrocoracohumeral ligament, a short band of tissue that connects the humerus to the shoulder joint [image]. The ligament balances all of the converging forces, from the pull of the massive pectoralis muscle in the bird’s breast to the push of wind under its wings.
But the researchers weren’t done there. They wanted to delve into implications for long-extinct birds … and went about their tests in a manner most odd:
Curious if the same was true of ancient animals, the researchers put some alligators on a treadmill and studied their gaits and used X-rays to make more computer models. The ancestors of modern alligators were closely related to birds.
They found that alligators use muscles, not ligaments, to support their shoulders. A look at fossils of Archaeopteryx, thought to be the first bird, revealed its flight mechanism to be unlike the pigeon, too.
The article includes this cool computer-animated drawing of the inner pigeon workings, but, unfortunately, nary a picture of an aligator on a treadmill.
