Feared as disease carriers, bats can save lives
No species of animal has been more demonised in the modern era than the bat. First, Bram Stoker’s Dracula meant horror lovers everywhere linked the winged Chiroptera to the myth of human vampires: “he can be as bat, as Madam Mina saw him on the window at Whitby.”
Then along came Covid-19, with scientists’ assumption (not yet disproved, if widely challenged) that the virus leapt from bat hosts in rural caves to mammals that ended up in the wet market in the Chinese region of Wuhan. Once again, the bat was the villain. But as a devotee of bats – someone who has studied their behaviour and biology for nearly twenty years – I feel we should align ourselves with the Chinese concept of bats as fu, or good fortune. Not to be confused with flu, of course. Certainly, we should take a better look at what we can understand from bats, since they make up a fifth of Earth’s mammals.
As a naturalist born in an animal sanctuary, I’ve always had a thing for bats. I loved watching them dart about the garden, untouchable, in and out of the aviaries where the poor, sick birds we were caring for clung to their perches and their lives.
In Chinese arts and crafts, a bat is a male symbol of fertility, usually depicted close to the female one, a peach, because the wild ancestors of today’s peach trees depended on bats to disperse their seeds, and us humans depended on them for our shared harvest. It’s a time-honoured salute to a perfectly stitched, reciprocal relationship. They sow, we farm, everyone reaps.
Bats have around 65 million years of evolution under their wing, while we modern humans began walking the planet a mere sneeze of a few-hundred-thousand years ago. Bats are the only mammals able to sustain flying for a prolonged period, while echolocating their prey. In fact, bats aren’t blind and the non-echolocating fruit bats can see very well indeed. But echolocation in the dark creates a superior sound picture that can be even more highly detailed than conventional eyesight, able to identify the twitch of a cat’s whisker.
As mammals, humans have a similar skeletal structure to bats, except that their wings substitute our hands, and their knees bend the opposite way. In fact we share 95.8-97.4% of their DNA. The main difference is that they have adapted over millennia to use their physical attributes much more fully and connectedly than we do. Unlike most humans, they can also rotate and stare all the way up their back passage. They can flip on their feet so as not to urinate in their own face.
Humans have learned a lot in the past century by examining bats. Rudimentary military sonar exploited the Doppler effect (as bats do) in 1918, while fully-fledged echolocation was first employed by observing bats in 1938 by Donald Griffin and Robert Galambos in a secret military project just before WWII. Today, the US Navy are trying to map a 3D world of sound deep underwater by studying bats’ brains. Ostensibly they want to distinguish mines from natural objects, among other things. So far, however, they’ve only managed to develop technology that takes twenty to 30 seconds to process an echo in the deep sea, whereas bats take less than a tenth of a millisecond in the sky.
The downside of all this innovation is that it’s too often developed for war and defence, which is where all the funding is. Furthermore, the US navy’s sonar testing exercises disturb, injure, strand and sometimes kill sea mammals. Effectively, they are using bat know-how in a way that potentially destroys endangered marine life like killer whales, dolphins, seals and walruses.
It’s clear we have far to go when it comes to harnessing bat ingenuity to benefit the planet. We can learn so much more from other species about how to take positive action and waste fewer resources: to borrow and fix, not blame and blight. Draculin, the inspiringly named anti-coagulant for humans, developed from the saliva of a vampire bat, is one such borrow and fix. The bat spittle contains properties that keep their victims’ blood runny so they can keep returning to sup. For us, it’s helped create a life-saving blood thinner that can prevent certain types of stroke and blood clotting.
Other benefits for humans include Griffin and Galambos’ use of the Doppler effect in peacetime for ambulances and X-rays. It has also helped significant human applications such as helping blind people “see” through sound, by using clicks or tap sticks to harness their bat-like, super-sense hearing and echolocate their surroundings. Bats helped give birth to human sonar.