Posted 29th Aug 2014
The secret life of a bat is one rich with tales as they intrigue and mystify us with their nocturnal habits. Though sometimes misunderstood, these compelling creatures are actually highly intelligent and of international importance in environments across the world. Join us in celebrating them this International Bat Night (from 30th to 31st August 2014)
Glimpsed at dusk as they dart through the night sky are mysterious mammals that can be as light as a pound coin, yet they have a reputation to be feared as the subject of many fictional vampire tales. These creatures of the night are of course bats, and together they make up more than a third of the UK’s native land mammal species. They’re also the world’s only flying mammals and we’re lucky enough to have 18 different species in the UK, with 17 known to breed here. Many of these species are rare – it is thought that there is just one greater mouse-eared bat left in England – and sadly they’re in decline due to loss of habitat. Their role in environments across the globe is very important, with over 500 international plant species relying on bats to pollinate their flowers, and here in Britain they serve as an ‘indicator species’ to help us monitor aspects of biodiversity and the health of the natural environment through their population numbers.
At this time of year the mating season has started and before long bats will be seeking their hibernation sites ready for the cold winter months when food is scarce. As they flit through the night sky the males will begin attracting their mates through a series of special purring, clicking and buzzing calls that let females know where they are. After mating, females will then store the sperm until spring and come May they will begin forming maternity colonies, congregating to give birth and raise their young together whilst males roost alone. Bats usually only give birth to a single pup, which are born tiny, less than an inch long, but in just six weeks they are big enough to come off their mother’s milk and begin catching insects for themselves. Incredibly some bats, such as the common pipistrelle, can eat up to 3,000 insects in a single night, with critters such as midges, mosquitoes and flies their cuisine of choice. Most of their prey is caught and eaten mid-flight using a special sonar system called echolocation. As bats fly they make high-pitched sounds that return echoes, which gives them information about anything ahead, including the size and shape of an insect. These shouts are inaudible to the human ear but can be heard with a bat detector – a useful instrument that can help to track them down. If you’ve ever heard the saying ‘as blind as a bat’ you would assume that bats can’t see, but in fact their vision is almost as good as ours, it’s just their hearing is more important when they’re out catching prey in darkness. The brown long-eared bat (pictured above left) can even hear the almost silent sound of a ladybird walking on a leaf.
When they’re not out hunting for prey, bats roost, often together, throughout the year, most commonly living in hollow trees, caves, under bridges, buildings and in roof spaces. They hang upside down so that they’re able to spread their wings ready for take-off, something they couldn’t do if they hung upright by their thumbs. The tendons in their legs are designed to support the weight of the bat, causing the toes and claws to automatically grip and keep them hanging upside down, even when they’re sleeping. They’re very clean animals too, spending much of their time grooming themselves and each other. With a lifespan of up to 30 years they have a lot of time to kill in between mating and finding food.
Bats come in all shapes and sizes, with the smallest species – the pipistrelle (pictured below right) – weighing just five grams with a wing span of 18-25cm, and one of our largest bats, the noctule, which still only weighs up to 40g and is smaller than the palm of a hand. In 2010 a new bat species was discovered here – the alcathoe, which went undetected for so long due to its close similarity to the whiskered and Brandt’s species. No two species are quite the same with some living in the countryside whilst others prefer towns and cities. They can be spotted flying both high and low, with the best chance to see them around sunset or sunrise in warm, dry weather. You can also help to attract bats in your garden by creating a space rich in flying insects. Try planting so that there is something that will flower throughout the season – night-scented flowers such as bladder campion, night-scented stock, sweet rocket, evening primrose and honeysuckle are particularly good. Climbing plants are also valuable as they provide bats with shelter as well as a concentration of insects. You can also build or buy a bat box and hang it on or near a tree where bats are known to be present, though hang it high – at least three metres from the ground – to protect them from pesky predators.
So often misunderstood, bats are truly intelligent creatures who are more closely related to humans than they are mice. Though frequently depicted as the phantom of Hallowe’en, chances are they’ll be building up fat stores ready for winter come October – so keep your eyes peeled and you might just catch a glimpse.
By Natalie Mason
Images courtesy of The Wildlife Trusts: Harry Hogg, Amy Lewis, Bethan Humphris