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Be nice to bats this Halloween
Slow Views

Be nice to bats this Halloween

Tuesday 26 October 2021

These wondrous flying mammals have had a bad rap, thanks in no small part to Bram Stoker. They deserve our friendship


If I shine a light in your eyes on a dark night, your eyes will not shine back. Nor will those of tarsiers, monkeys and our fellow-apes. The eyes of dogs and cats will, along with those of most other mammals; I have located hunting lions in the dark by using a spotlight to seek out their eyeshine. 

Lions are at home in the dark, likewise cats and dogs. We humans are not. We lack the tapetum lucidum, the device that aids low-light vision – and causes eyeshine. In the dark we are out of our depth: caught in an environment in which our senses struggle to cope. We don’t know what’s going on, we don’t know where we are going and worst of all, we don’t know what’s around us – or who.

Throughout our history we have feared the darkness and loved the light. Our ancestors’ control of fire brought warmth, sure, but that was a bonus. Far more importantly, it brought safety and security for as long as the night – or the fire – lasted. 

We celebrate light. At the December equinox, the moment when the hours of daylight start to increase in the northern hemisphere, we hold the biggest feast of the year, Christmas. At the time of the first full moon after the March equinox – when daylight hours outnumber those of darkness – we celebrate Easter. For us light and goodness are one and the same, just as darkness is evil. The idea of evil as the Dark Side predates Star Wars by a good few million years. 

But on the day before All Saints Day – the feast of All Hallows – we turn to the forces of darkness, and, in a joco-serious manner, many among us revel in creepiness, darkness, death, bones, ghouls, ghosts – and above all, bats. For this is Halloween.

Bats are singularly miscast in the role of bringers of evil. They do very little harm to humans: most of the bats that live in Britain hunt for insects and infinitely prefer to keep out of the way of humanity. But across the country, in a tradition that was exported to America from Europe with the first settlers and later reimported in a new and jollier form, people will celebrate All Hallows Eve with images of bats.

This is because bats love the night. They are at home where and when we are not. They are creatures of the dark, so naturally we associate them with evil, with the devil – or to be more accurate, with the deepest human fears.

When the bodies of bats are seen plain, they are charming little furry things, like the jolliest kind of shrews, which are their ancestors. But the wings are bare skin and that gives many people the creeps: odd, since we are bare-skinned mammals ourselves. Bats make it into the witches’ brew in Macbeth, the ingredients for which is a roll-call of traditional flesh-creepers: “wool of bat” goes into the cauldron along with eye of newt, toe of frog and all the rest. 

But there is an additional aspect to the fear and loathing that bats inspire, and that is vampirism. Across uncountable millennia humans have feared that dreadful things might suck the life out of us when we are asleep. Now we associate bats with that fear.

The myth of vampirism is a long-established tradition in many cultures: walking dead who steal your life for their own ghastly purposes. But blood-drinking bats weren’t known in Europe until the 16th century; they got their name from the ancient fears of vampirism. They were first described for science in 1810.

There are three species of vampire bat, all of them from South America; two of them feed only on birds while the third, the common vampire, feeds on the blood of mammals. They are hardly creatures of nightmare in their natural state: a body less than four inches, wingspan seven inches. 

They are agile crawlers: they land on the ground near a potential victim and creep across the ground. They make a painless bite on the ankles of wild mammals and domestic stock; their saliva contains a powerful anticoagulant and rather than sucking, they lap up the flowing blood like a cat with a saucer of milk. They have been known to feed from the toes of sleeping humans, but that’s pretty unusual. They are known to practise altruism: a hungry bat will, after an unsuccessful hunt, beg from a neighbour, who is often unrelated. The neighbour will regurgitate a nice warm meal. They are thoroughly admirable animals, in short.

But the twin horrors of night-loving bats and of nocturnal blood-drinkers became conflated, and so the modern archetype of horror arose in the form of what we now think of as vampires. The most likely prototype appears in a novel of 1819, The Vampyre, by John Polidori. A series of penny dreadfuls with the title of Varney the Vampire was printed 1845-47.

And in 1897 came Bram Stoker’s epistolary novel Dracula and the cult of the undead count has never died: growing stronger with the years, feeding on our own delight in fearful things. The first Dracula film was released in 1921: so there’s a centenary for you. There have been many subsequent films of horrors, often with Christopher Lee as the count, many semi-jocular examples like Billy the Kid vs Dracula, more recent versions with Buffy the Vampire Slayer. 

These works of the last couple of centuries explicitly connect Dracula with bats. In Stoker’s novel the count shapeshifts into a bat; he also appals Jonathan Harker by climbing down the castle wall face-down. The count is traditionally dressed in a leathery cloak, reminiscent of the wings of a bat. Like a bat he has apparently miraculous abilities to operate in darkness. Dracula represents a double-dose of fear.

Bela Lugosi plays the vampire count in ‘Dracula’, directed by Tod Browning, 1931

In the wild world there is plenty of food available at night, but not every wild creature can exploit it. You can find it in the open skies and on the trees. If you take on the challenges of the night you have an ecological niche with comparatively little competition. The night represents a glorious opportunity for the forces of evolution: and bats seized it with both wings.

Many creatures can manage a glide: lizards, frogs, squirrels, lemurs, even snakes. But only four groups have evolved true flight: birds, insects, the extinct pterosaurs – and bats. This was such a brilliant breakthrough that it has made bats one of the most successful mammal groups in existence, second only to rodents in diversity: one fifth of all mammal species are bats: more than 1,400 of them. They are found everywhere outside extreme deserts and the poles.

They range in size from the giant golden crowned flying fox with a wingspan of five and half feet to the bumblebee bat – a species I saw in Borneo – an inch long and a wingspan of less than six inches. For convenience (rather than precise taxonomy) they are divided into two groups: megachiroptera and microchiroptera: big hand wings and small hand wings.

The megas feed mostly on fruit, pollen and nectar, and few of them find their way by echolocation: after all, they are hunting a prey that doesn’t move and evolution doesn’t go in for unnecessary luxuries. The micros mostly hunt for insects. (There are other exceptions than vampires: some species take fish, night-flying birds, small mammals and there’s a species, the fringe-lipped bat, that specialises in frogs. At least two species hunt other bats.) 

But it’s the great resource of night-flying insects that preoccupies most bats. They catch them in their tails, like a net, and flip them to their mouths in flight: quite a trick. Mostly these are consumed on the wing.

The bats track them down by means of sonar. They make sounds, and listen to them as they bounce back from moving and static objects all around them. This poses an obvious problem: how do they avoid getting confused by the sound of their own voices? The answer is that they shout at a pitch beyond the range of their own ears: they can only hear the lower-pitched echoes. This requires them to calculate the Doppler shift, the change in pitch that occurs when the source of the sound is moving relative to the listener. (Radar, which bounces radio waves rather than sound, as the name suggests, operates on a similar principle to sonar. It was invented around the same time that the bats’ secret was discovered, but there seems to be no correlation either way. Just one of those rum coincidences.)

It is possible to listen to bats at work, and to detect their presence on black nights when human sight is little help. I have a bat detector, a device that listens to bats and plays back their ultrasonic calls at a pitch at which humans can hear them: you can fill the night with what sounds like thrilling phrases played on a bongo drum. This is good fun itself, and with experience and skill (both of which I lack) you can distinguish one species from another from the sound. 

Flying Fox Bat during the day time.

Bats tend to be more dominant in the imagination than in the experience of most people in the developed world. They are seldom associated with the glamorous sights of wildlife adventures: the great whales, lakes with a million flamingos, the plains of Africa. 

But bats provide one of the greatest wildlife spectacles of the world, and it can be experienced every year from October to December at Kasanka National Park in Zambia. The straw-coloured fruit bat is one of the mega bats, a mobile and highly social species that commutes around Africa in hefty groups following the fruit. They are frequently found in colonies of a million or so.

But in December an annual fruiting bonanza brings them together in one vast group: and at such times there are ten million of them roosting in one small clump of woodland, in such numbers that you often hear branches breaking under the weight of hanging bats. These are not the little insect-eaters that fizz around our heads on an English night: they are chunky animals with a wing span of more than two feet. In terms of bioabundance and biomass they provide a profound and powerful experience to visiting humans.

They leave at dusk and boggle the human mind with their crowds: these are numbers for astronomers rather than biologists. You see them leaving in an endless steam: and always it seems, there is one of them heading back against the tide, having apparently left the gas on.

This spectacle is now threatened by illegal commercial farming in the neighbouring Kafinda Game Management area. The Kasanka Trust notes that Lake Garo Industries have been illegally expanding their operations, which are, they say, clearly visible on satellite imagery. Kasanka Trust manages the park; I have had dealings with them as a council member of the UK-based World Land Trust.

Since we humans are creatures of the daylight we seldom notice bats, and for most of us, it is a matter of comparative indifference as to whether or not they continue to exist. But there are problems for bats in many places. 

Accurate surveying of bats is a specialist job: it’s a problem with most creatures of darkness. But as bats vanish, they begin to attract our attention. They suffer from the decline of insects, light pollution and the loss and disturbance of their roosting place: these days many bats use abandoned human constructions.

Straw-coloured fruit bats returning to their daytime roost at sunrise, Kasanka National Park, Zambia

Two years ago a bat enthusiast called Scotty Dodd found a small colony of bats – with young – in a derelict, once-handsome stable block in Sussex, and identified them as greater horseshoe bats. And that was quite a find. In recent years, the species has been considered a West Country specialist; the nearest known population was 70 miles off in Dorset. It was 100 years since they had bred in southeast England: they had declined 90 per cent in the 20th century.

This tiny colony could be the start of a return. The Vincent Wildlife Trust already owns and maintains more than 40 bat roosts in the country: half the British population of greater horseshoe bats is on Vincent reserves. Now they are trying to acquire this one. It is in a poor state and needs to be refurbished. The Trust has managed to raise a deposit; in order to proceed they must raise £350,000 in two years.

The bats we fear so much – not for themselves so much as for the darkness in which they have their being – are not, it seems, without their friends. It is, I think, time to bring them inside our circle of concern. Bats have been tricked for long enough: perhaps it’s time that we treated them instead.

Photographs Getty Images, Alamy, John Kobal Foundation, Nick Garbutt/Barcroft Media