Why do bats hang upside down when they sleep?

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Bats are one of the most interesting creatures in the world. The fact that they are nocturnal has caused them to be the basis of many vampire myths. Even more interesting than that, they sleep upside down! Who else does that? OK, sloths do but they do it in a more lazy way, the bat way always appears more menacing. So why do bats sleep upside down, and how?

Bats sleep upside down for a number of reasons. The main reason is to do with their approach to flying. Bats lack the power that other birds have in their wings. This means that a bat can not take off into the air from a standing position. Instead a bat has to fall first and fly from the falling position they are in. While a running start would also work a bats feet are too small compared to the rest of its body to be effective. Thus, they choose to start by falling. By sleeping in an upside position it means that if any predators do come they can immediately fall and fly away. 

The second reason is entirely predator based. Bats sleep while its predators are awake. Most humans and animals are not nocturnal so bats need to sleep somewhere they feel safe. It turns out that they are often safest hanging upside down where predators tend not to look. While many people believe they will only find bats in caves, in reality they can be found under bridges, in trees, in garden sheds and more. They generally just want to choose somewhere that is quiet and dark to allow them to go unnoticed. 

This brings us to the important question of how bats hang upside down for so long? If you have ever tried hanging from a bar upside down you will know how quickly your head rushes with blood and how quickly your legs get tired. The blood rushing to your head is simply down to our anatomy. Blood fails to pump upwards and so it all goes to your head making you feel light headed. Bats don’t have this issue. Your legs get tired because the tendon used to grip the bar in your leg is attached to a muscle. The muscle will tire out eventually and you will no longer be able to hold the bar. 

Bats hold on to bars with their tendons as well, but their tendons are not attached to any muscle. This means that when a bat locks its tendon around something, and hangs underneath, its own weight is the driving force in keeping the lock closed and it is not using any muscles. This means that bats would never tire from this grip. In fact many dead bats have been found in this very position. Unless something knocks them from their hanging position they will stay there when they pass away!

We hope you enjoyed this little bit of insight into the lives of bats. Many people seem to be afraid of the little creatures but as in most cases, that fear is usually driven by the unknown. Once you know a little bit more about these incredible creatures, you know how impressive they are.