I’ve mentioned in previous chats that I’m building a species based on the Mexican free-tailed bat, or Tadarida brasilienses.
Similar to pseudodragons, Tadarida brasiliensis has a relatively long tail and high sensory abilities. Additionally, the Mexican free-tailed bat is the fastest flier in the animal kingdom. I imagined all these traits would lend great detail to my sci fi world building.
The thing is, I know a little about flight. Lift. Thrust. Drag. Yup. Definitely concepts I’ve learned. But what does all that mean for an animal known to have a unique flying ability compared to birds and insects?
Time to dig into the particulars of bat flight.
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Basic Bat Wing Biology
Bats have been given the order name Chiroptera, meaning “hand-wing,” because their wings are similar to human hands. The four bat “fingers” are long and slender to allow them to support, spread, and manipulate the layer of skin that we refer to as a bat wing. This skin incorporates blood vessels, nerves, and tendons–the whole of which comprises the wing membrane.
The thumb, which extends slightly above the bat wing, typically has a sharp claw and is used to assist in climbing.
With this in mind, it’s easiest to think of bat flight as being like swimming. They row through the air, adjusting the movements of their fingers to quickly change direction. The strong chest and back muscles power their upstrokes and downstrokes, which provide thrust and lift.
How Skin Affects Flight
Birds have wings made from keratin feathers. Having a wing constructed primarily of dead material means that birds have limited control over their wing surface shape. By contrast, bat wings are constructed with living skin. Bats are able to make micro-adjustments in flight to stretch their wing membrane and affect lift.
Many bats also have a tail membrane. Like the wing membrane, this is a stretch of skin that connects the otherwise independent tail and legs. This feature is thought to have a hand in maneuverability. There is also some research suggesting that this tail membrane allows bats to stop quickly.
Like the wing membrane, the tail membrane can be easily damaged due to how thin it is. But, also like the wing membrane, it heals quickly–suggesting that both membranes are very important for this animal’s survival.
How do Mexican Free-Tailed Bats Stand Out?
I mentioned that the Mexican free-tailed bat is the fastest flier in the animal kingdom. And I imagine some of you immediately thought a falcon. And it’s true, peregrine falcons are known as the fastest fliers, but their fastest speed is diving speed, which means their top speed is aided by gravity.
What Mexican free-tailed bats are known for is fast horizontal speed–meaning their fastest recorded flights are roughly parallel to the ground. While the peregrine falcon has a top horizontal speed of 110 kph / 68 mph, Mexican free-tailed bats fly at a top speed of 160 kph / 100 mph.
Scientists are still learning about bat aerodynamics as well as what makes these bats, in particular, so fast. Generally, though, body shape appears to have a significant role. Compared to other bats, Mexican free-tailed bats have long wings–a feature that’s synonymous with faster flight.
Additionally, the reduced tail membrane for these bats is thought to increase their aerodynamics. Further, their uniquely strong muscles allow efficient and long-lasting flight.
Are Mexican Free-Tailed Bats Really the Fastest Animal in the World?
Interestingly, the discovery of this bat’s fast flight is fairly recent. As the ability to measure flight speed evolves, scientists may find an even faster animal. But as of now, Mexican free-tailed bats are considered the fastest animal on Earth.
Until next time, stay curious.