Thread by @AlexPetrovnia

Happy (early) Halloween! For today's science thread, let's talk about bats. More specifically, let's talk about the incredible diversity and adaptations of bats. 🦇🧵

Most people are aware that bats are to be found most places where people can be found, but many people don't realize that bats occupy almost every biome and habitat on earth. From rainforests to deserts to plains to taiga - you'll find bats.

Many people also think of "bats" as one animal, when in fact, there are over 1,400 identified species (so far)! It's estimated that bats alone may make up 1/5th of all mammal species, making them one of the most successful groups of mammals currently.

Bats in general can be divided into two major categories - megabats and microbats. The most common distinction between these two groups is, as the names suggest, size. Typically, megabats are fruit eaters and do not echolocate to find food, while microbats are insect eaters.

Bats, as we've shown earlier in this thread, come in a staggering variety of shapes and forms. While many bats eat insects or fruit, there are bats that eat flowers, nectar, pollen, leaves, fish, small animals, blood, and more.

Bats are often important species in their environments, often maintaining insect populations and serving as important pollinators.

Bats overall provide an enormous array of ecosystem services, and are incredibly helpful to humans. So why do they have such a spooky reputation?
The answer lies partly in colonialism.

Around the Victorian era, expeditions into "exotic" lands became increasingly popular.
One of these "exotic" lands was deep into the rainforests of South America, a region which exhibits the highest species diversity of bats in the world.

One of the most prominent features of many of the bats found in this region is the huge variation in nose and ear shapes. We now know that this variety has a lot to do with channeling sound for echolocation, but the Victorians were frightened and fascinated by these faces.

In particular, the Victorians were fascinated by the tales they had heard of Vampire Bats. There were theories that the nose and ear flares found on many South American bats were indicators of bloodsucking tendencies.

This was around the same time that celebrations of what would become Halloween were becoming more popular, and these strange and frightening illustrations of animals from far-away lands quickly worked themselves into Halloween tradition.

"But Alex!" you may be thinking, "Bats carry all sorts of diseases and are dangerous, surely they've earned some of their spooky reputation!"
The answer to this, as is often the answer in science, is, "kinda."

Bats *do* pose a serious disease risk to humans (please do not handle any bats unless you are properly trained and vaccinated), but almost all bat-human encounters are human-initiated. Bats, in general, will do all they can to avoid big scary humans.

And bats do carry many diseases, especially viruses, that can be very dangerous to humans. But this isn't because bats are dirty or scary.
It's because they're social and adaptable, much like us.

Bats are *highly* social as a rule. The largest bat colony (that we know of), exists in Bracken Cave in Texas. There, a single colony consists of 15 MILLION Mexican Free-tailed Bats.

But living in large groups can have consequences. One of these consequences is that diseases can spread quite easily between individuals. Bats in particular spend a lot of time together - they "talk" to each other, groom each other, and sleep very close together.

Bats also are the only mammals capable of true flight. This means they can cover great distances very quickly. Just as humans inventing jet travel means we can spread diseases more quickly, bats are vulnerable to diseases spreading between communities.

Many bats also migrate, travelling extremely long distances in their yearly cycles between mating, hibernation, and finding food.

But plenty of animals live in large groups and migrate long distances. What makes bats such a viral spillover risk?
It's because they're flying mammals.

Mammals, by definition, are warm-blooded. This means we expend energy to keep our body temperatures higher than our surroundings. We can also generate heat by moving our muscles. (Think about how you sweat when exercising, or shiver to keep warm.)
In short, flying is a workout.

Bats have to be able to withstand huge fluctuations in their body temperature. Some bats' body temperatures get up to as high as 106 degrees F (41 degrees C) during flight!
But what does this have to do with viruses?

Any virus that is able to survive in a bat is able to survive the body getting up to these extremely high temperatures. Meaning that any virus that is able to survive in a bat is functionally immune to most human fevers, the first line of defense in our immune system.

But in spite of all of this, bats are MUCH MORE threatened by humans than vice versa. Bats provide essential ecosystem services almost everywhere and will avoid humans if they are at all able to. Bats don't attack people!

Over 200 different bat species, in 60 different countries, are currently considered "threatened" by the IUCN. Bats all over the world desperately need our help to survive and thrive. Some important resources to help save bats can be found here:
batcon.org/our-work/endan….

In general, some good rules to follow to protect bats are to leave them alone and to educate other people about them! Bats are amazing animals with an unfortunate (and undeserved) reputation, and are not in any way dangerous unless humans invade their spaces or try to touch them.

Bats are my favorite animals and I could ramble about them forever, but this thread is getting long so I'll leave it here. Feel free to ask bat questions or share your favorite bat facts below!

I'll add a #BatFact to get us started. While researching to verify the info in this thread, I learned that new research shows that baby bats "babble" while they're learning to "talk" to other bats.
smithsonianmag.com/smart-news/bab…

Talking so generally about bats is difficult! In the near future I plan to do a followup thread to this on the little brown bat and white nose syndrome specifically, so stay tuned!

Writing like this is my job and takes a lot of time and energy. If you feel I've earned it, please consider dropping a tip to my venmo, @AlexPetrovnia.

As promised, HERE is the followup thread to this one about little brown bats and white nose syndrome:

https://twitter.com/AlexPetrovnia/status/1446914500762947584?s=20