Animals Are Awesome

This is a great gray owl, looking very intimidating in an adorable sort of way.

Owls have developed a wing structure that allows them to be—for all practical purposes—completely silent in flight. Noise generated in flight is produced by the vortices formed as air flows over a wing, and is proportional to the size of the vortices. Owl wings have tiny projections along their leading edges, which generate a large number of small vortices, keeping noise to a minimum. Furthermore, the fringe at the wings’ trailing edges (which, by the way, have a smaller number of hooklets at the end of the feather barbs than most birds) help break up waves that are propagated as air flows over and down. The soft down covering much of the rest of the owl further helps to absorb any sound above 2000 hertz, making them almost completely silent.

More bird-related trivia: the shock absorbing capacity of a woodpecker’s skull!

Another interesting avian adaptation for light weight, yet practical bodies: Tucan beaks!

The top image is the beak’s outer layer, which is made up of keratin hexagons (for context: keratin is the stuff your finger nails are made out of). This allows the beak to be relative strong and durable, and the layer is thin enough to remain light.

The second image shows the bony matrix (referred to in the third image as “foam”) that makes up most of the beak’s structure. A tucan’s beak makes up roughly 1/3 of its length, yet only weighs 1/20th of its total body weight. The matrix is made of ossified fibers and sheets, similar to bone but far more porous.

Storm-petrels are sea birds that feed on planktonic, drifting crustaceans and tiny surface dwelling fish. They do so by standing on the surface of the ocean using their webbed feet, while facing into the wind, wings raised, to catch the air currents. The air causes drag opposed to that of the water, which keeps the birds stationary (or floating slowly backwards, depending on the wind strength and water currents). In a lack of wind, storm-petrels will rapidly flutter their wings to remain above the water.

Because it is disadvantageous for penguins to leave the nest to relieve themselves, they instead turn away from the nest and, taking wind trajectory into account, shoot their excrement away from the nest to a distance of ~40cm.

Because birds have very high metabolic rates, they must eat a vast amount of food relative to their body weight. Yet because, usually, birds are flying animals, they must be light-weight. This means that their digestive systems must lightweight and efficient, and their musculature and skeletal structure is often as minimal as possible. Thus, birds have very few muscles in their heads compared to other animals. There are only a handful of tiny muscles responsible for opening and closing the jaw, limiting the strength of their bites.

To make up for this lack of bite strength, different birds have grown a range of adaptations. Sharp beaks, oral pouches to retain food, and oral papillae to grab onto food are common physical accoutrements.

Penguins have oral papillae (which are made of keratin) in order to grab onto and hold slippery fish in their mouths. Penguins do not fly, so they do not need to be light, but they still retain characteristics of their class, Aves.