Why do bats hang upside down?

Question of the month

Why do bats hang upside down?

By Hannah Van Hesteren, Bat Advice Officer at the National Bat Helpline 

Mark Hamblin/2020VISION

When you think about bats, you probably think of mysterious little creatures hanging upside down from their feet with their wings wrapped around their bodies. And you’d be right, some of the time… 

Squeezing into tight spots! 

The truth is, most bats that live in the UK don’t do this at all. We sometimes call them ‘crevice dwellers’ because these bats much prefer squeezing themselves into little gaps and cracks in trees and buildings, so they’re really well hidden away.  

Some of our more common bats, called pipistrelles, are so small they could squeeze into a matchbox, but you’re much more likely to find them living under roof tiles of houses instead of hanging upside down like you might see in films. 

 

So which bats do hang upside down? 

Two of our bats species clearly have been watching the movies and will hang upside down, gripping on with their feet, in barns, lofts and caves.  These are called horseshoe bats, named after the distinctive horseshoe-shaped nose. You’d be very lucky to see horseshoe bats because they’re rare and live only in the southwest of England and the south of Wales.  

Greater horseshoes are about the size of a small pear whereas the littler lesser horseshoes are about the size of a plum. Their small size means they don’t get a rush of blood when they hang upside down which might otherwise make them dizzy.  

bat

Dale Sutton/2020vision

Gymnasts of the sky 

Horseshoe bats have special tendons in their legs (the parts connecting muscles to bones) which means their feet naturally grip on tight, even when they’re relaxed. They can even easily hold on with just one of their feet at a time! This, plus their backwards facing knees, make it easy for bats to sleep and even hibernate upside down.  

Dangling freely like this gives horseshoe bats a good clear view so they can see and hear all around them before they decide to take flight for the night. All they need to do is spread their wings, let go with their feet, and they’re off!  

This also means they are good at quickly escaping predators like owls, and hanging upside down helps them find good hiding places too. It must be hard to land on your feet when you’re landing upside-down but luckily our horseshoe bats are the gymnasts of the sky and land perfectly with a somersault.