Urban Wildlife: Bat Facts

Recently, I’ve been spending a fair bit of time at the Kew Bridge Eco-Village in west London. This fascinating project aims to create a sustainable community garden on an acre or so of derelict urban land which has been the subject of a now decades-old planning wrangle between the prospective developer, local residents and the borough council.

Sitting empty, unused and unloved on the banks of the Thames for almost two decades, the site was soon taken over by Mother Nature, and the eco-village is now home to an amazing array of wildlife, including bees, butterflies, ladybirds, foxes, a rare type of biting spider (!), as well as several neighbourhood cats who have obviously viewed the site as their very own private feline fiefdom for almost as long as it has been derelict.

I first visited the eco-village back in the summer, when the whole area was covered in the familiar pink of patches of rosebay willow-herb and the vivid purples of newly-seeded buddliea bushes, as well as any number of other, more curious and less common plants and herbs – all of which attract wildlife of all kinds, even on such a resolutely urban patch of land as this.

However, despite the fact that they are becoming more and more common in urban areas, and that the eco-village provides an ideal habitat for them, there is one species I have yet to see there – bats.

Everyone has their favourite animals, and bats are definitely one of mine. Not only are they remarkably cute little creatures (they are, honestly!), but they also play a crucial part in the maintainance of a green and healthy environment, which makes them doubly cool in my eyes. They really are extraordinary – and extraordinarily important – animals.

So here are a few fascinating Bat Facts to explain precisely why that is…

– Bats are the only true flying mammal, which makes them unique in the animal kingdom, although they actually make up as much as a quarter of all mammal species in Britain (and a fifth worldwide). Some British bats are much less common than others, but they are all threatened by the encroachment of humans onto their habitats.

– Many people would understandably assume that bats live solely in the countryside, but it is becoming more and more common to find them in urban habitats, where they roost in buildings and feed in local parkland. I have certainly seen bats in London. All bats need certain things in their habitat, whether rural or urban, in order to survive, including water, trees (which provide both food and navigational landmarks), and somewhere quiet and sheltered to protect them against predators and allow them to roost.

– Bats can live up to about the age of thirty, which makes them one of the longest-lived of all mammals. And they go back a long way. Fossilized bats have been found which scientists calculate are in the region of fifty million years old. These fossils show that these ancient bat ancestors were very similar to 21st century bats, suggesting that they have actually been around a lot longer than a mere fifty million years.

– The scientific name for bats is Chiroptera, which translates as ‘hand-wing’. If you look at a bat with its wings outstretched, you can see exactly where this name comes from. In fact, bats appear to have shared a common ancestor with us primates at some point in their evolution, which makes them genetically closer in some ways to humans than to other flying creatures like birds, or even mice.

– In the UK alone, there are seventeen different species of bat (of 1,100 worldwide), including a selection of bats with wonderfully descriptive names – such as the whiskered bat, the soprano pipistrelle, the Natterer’s bat, the lesser horseshoe bat, and the greater mouse-eared bat. All seventeen of these British species are very small creatures indeed, ranging from the pipistrelle, which weighs a little less than a £1 coin (approximately 5g), to the greater mouse-eared bat, which is the biggest bat in Britain, but would still easily fit on the palm of your hand.

– All of these different species of British bat are also insect eaters, and they all hunt their favourite bugs in different ways. Most bats actually catch and eat their prey on the wing, which is probably the very definition of fast food. And they need those calories. Flying and hunting expends a lot of energy, meaning that even the tiniest bat can eat upwards of 3,000 insects in a single night.

– Bats are very clever hunters. They aren’t blind, they actually see almost as well as humans, but they have a very acute sense of hearing, and they use a natural sonar-like system called echolocation to track their prey and estimate distance at night (which puts them at a distinct advantage, no matter how quietly that tiny midge thinks it is flying through the dark). It is the very existence and super-accuracy of echolocation which can finally and fully disprove that old canard about bats getting caught up in your hair.

– At this time of the year, most bats are quite sensibly contemplating hibernation. They’ll have mated (the female bat actually stores the sperm until it is safe to become pregnant in the warmer spring weather), and, like many mammals in autumn and winter, are getting sleepier and sleepier. In only a few weeks time, they will be hibernating somewhere cool and quiet until the spring.

– And spring is, of course, the time of year when baby bats start to appear. Female bats will group together in a ‘maternity roost’ to give birth, often at the same site every year. Bat pregnancies last between six and nine weeks, with some variation depending on the climate and the availability of insects. Similarly to human females, bats tend to give birth to a single baby, which they then feed and nurture for about a month until the baby bat is able to fly and fend for itself.

– It is during this maternity season that bats are most vulnerable to disturbance, but they are actually under threat all year round. This threat comes mostly from us humans, and mostly because so many of us do not understand how important bats are in the greater scheme of things. Despite the fact that all British bats (and their roosts) are protected by law, they are still threatened by everything from urban building work and renovations to loss of rural food sources, habitats and flightlines – as well as less obvious threats, such as intensive farming methods, lighting and wind turbines.

It seems that being a bat in Britain (and in other parts of the world) is an increasingly risky business, particularly for bats in urban environments. Rather than running from them, screaming, we should be admiring and protecting these remarkable and often endangered creatures. If the general public were aware of the good that bats do in keeping our natural world going – that they hunt insects, pollinate and re-seed plants, and that bat droppings make an excellent natural fertilizer, as well as providing enzymes used in the laundry detergents we use every day – I would hope that many more people would join me in wanting the best for these endearing and helpful animals.

For more information on British bats and helpful advice on the legal status of roosts etc., visit the Bat Conservation Trust website. If you are in America, try the Bat Conservation International website for useful information on bats there.