Bats: The fabled nightdwellers of the British uplands

In all the years I’ve roamed our uplands, I’ve seen very few bats, and none up on the high mountains. But there are parts of Britain’s uplands that support these night-flying mammals.

The valleys around mountains are going to be your best bet, as trees and water are two features bats look for in a habitat. Being in a valley will also mean a more sheltered environment, because if their prey can’t fly then it’s not worthwhile them doing so. One feature which rocky landscapes have that bats love are caves, though many bats have actually adopted the mining tunnels which proliferate our uplands as homes. A good example of an upland environment where a couple of species of bats may be seen is Malham Tarn up in the Yorkshire Dales. The key here is the cave-rich limestone landscape and proximity to water.

There are 18 species of bats in Britain, and the most widespread is the common pipistrelle which thrives in a variety of habitats. Many of the bat species occur only in southern England. The others are scattered in hard to define, closely guarded parts of our countryside, kept secret in order to protect what are creatures on the knife-edge of survival. It requires a license to handle bats.

All bats are nocturnal and feed on insects, which they catch in flight at night. They breed in the autumn, with the female capable of storing the sperm through the winter before allowing fertilization in the spring. Bats have just one ‘pup’ each year. The reason for this is that bats are long lived for such a small mammal (30 years isn’t abnormal), so they don’t need to produce large numbers of off-spring in a short time, as rodents do.

Talking of rodents, bats are basically flying mice. Their wings are constructed out of thumb hooks on the front of the wing, with the four other digits of the hand supporting the membrane. The legs are bent slightly backwards at the knee to enable the tail membrane to be supported. It all looks a little like those wingsuits that close-proximity fliers use when they throw themselves off mountains. Bats hibernate during the winter, their prey not being available. Some migrate to these winter hibernation sites. And yes, bats do roost/sleep/hibernate upside down. There are 19 families of bats worldwide, two of which hang out (get it?) here. Those two families are the ordinary bats and horseshoe bats, and we have two species of horseshoe bat – the greater and the lesser. The lesser horseshoe bat, though rare, is one species that will use old mine tunnels. Unsurprisingly north Wales holds a significant proportion of the British population.

Horseshoe bats are ugly critters, with a ‘U’ shaped fold of skin around the nostrils and large ears. That nose is where they emit sound from when using echolocation, enabling them to locate objects and prey in the dark. And those big ears are the receivers of that ‘bounced’ sound. Interestingly, ordinary bats emit sound in the ordinary way, through their mouth, and have much more rodent-like faces. Horseshoe bats have broad, rounded wings and fly in a leisurely way, not like the fluttering flight of ordinary bats, which have longer, pointed wings.

When roosting, horseshoe bats wrap their wings around them, like a cloak, while ordinary bats generally keep them folded to their sides. Horseshoe bats have rounded bodies and so can’t crawl like their ordinary relatives. For this reason their roost perch must have enough room to fly to. Those broad, rounded wings make maneuvering in tight spaces that much easier.

Bats all over the world are the source of much superstition, their mysterious nocturnal habits being the obvious connection with all things evil. My favourite bit of bat-related folklore is that if you carry a bat eye in your pocket, it’ll enable you to become invisible. Don’t go trying it though, because if you mess with those bats, the real law awaits.

BATS LOVE CAVES, BUT MANY HAVE ADOPTED THE OLD MINING TUNNELS WHICH PROLIFERATE OUR UPLANDS AS THEIR HOMES