Back in generation 1, when we were young and excitable, we began our journey with enthusiasm. What Pokemon would we catch? Where are the Pokemon hiding? It didn’t matter who showed up in the grass, we loved them all! That is, until we took the fateful step into Mount Moon. Inundated by Zubat after Zubat, many of us learned to hate this bat that continuously confused us. But generation 2 was a kinder generation, and somewhat redeemed Zubat upon the introduction of its fully evolved form, Crobat.
Crobat is, obviously, based on a bat. However, it has four wings instead of two. According to the Pokedex “As a result of its pursuit of faster, yet more silent flight, a new set of wings grew on its hind legs” (C). This fast and silent flight is one of the major traits of Crobat, as it is mentioned in many of its Pokedex entries. Bat wings are really just modified hands. If you look at a bat wing stretched out, you can see the long bones that resemble finger bones. The skin over these bones is leathery and so thin it is translucent in the right light. The substantial width of these wings allows the bat to propel itself from the ground (or branch or cave) by pushing air downwards, generating enough force to push itself up. Once in the air, the useful shape and lightness of the wings also allows the bat to glide through the air. The speed we can attribute to its extra pair of long wings, but how does it fly so silently?
One of the most notable animals with silent flight is the barn owl. Unlike most birds, you can rarely hear the swish of air that results from a barn owls wings. This is because the fine, primary feathers on the barn owls wings are separated to have a serrated edge, like a comb. This cuts the turbulence caused by their wings” into smaller units, which produce less sound. This is extremely useful to the barn owl, as it is able to sneak up on prey. It is easy to replicate this effect in real life. Wave a hand held paper fan up and down and listen to the noise. Then, slice the fan into segments and separate them slightly, like fingers, and wave it again. The sound caused by the fan will decrease as less turbulence is produced.
However, Crobat doesn’t have feathers, and so must rely on a different mechanism. Insects with wings can only control the joints at the end of their wings, so all they can really do is flap. Birds have more joins, and can therefore use the finger like bones in their wings to increase their manoeuvrability. However, the finger bones in bat wings are far more advanced, and a bat therefore has a huge amount of control over the shape and movement of its wings. Not only do they wave their wings up and down, but they can also subtly change the shape of their wings during flight.
Furthermore, the skin on the wing of a bat is stretchy and can balloon slightly when it pushes down. This allows more air to be utilised under the bat’s wings so it does not have to flap as much as a bird or an insect, even if it isn’t gliding. This makes the bat an incredibly efficient flyer.
Crobat may utilize this technique also. It possible that it can fly silently through a combination of needing to flap less and opting to glide, and also by subtly changing wing shape to catch up drafts noiselessly because its wing bones are far more advanced than an ordinary bat. It also has four separate wings that can be used individually to catch different areas of wind, in order to glide silently for long periods of time. Furthermore, the four wings may help to break the turbulence into smaller units, in a similar manner to the comb shape of the barn owl.
Obviously, the silent flight of Crobat is likely to be an incredibly complex system, but this may provide a very simple basis.