Hanging out with bats!

Ever wondered how they hang upside down when they roost without the blood rushing to their heads? Special tendons that lock their toes and talons in place allows them to grip tightly without exerting energy, and valves in their veins and arteries prevent the blood rush. Clever. Bats are true fliers with wings that resemble a modified human hand — imagine the skin between your fingers being larger, thinner and stretched. This flexible skin membrane and many movable joints make them agile fliers.

Echolocation

Just before sunset bats head out to hunt their prey of mosquitoes, midges, and gnats, and in order to locate their prey, they use echolocation, producing sound waves at frequencies way above human hearing. These sound waves bounce off objects and the sounds return to the bats' ears, which are finely tuned to recognize their own unique calls.

Bats in Portugal

I have never yet seen a bat here, but know they are here in their thousands and are quite happy in urban environments as well as the countryside. Around 25 species are known to be in Portugal, and legal measures are in place to keep them protected, including enforcement actions, with all bat species being protected by Portuguese law since 1967. Various worldwide wildlife conventions try to ensure that international trade in specimens of wild animals and plants do not threaten the survival of the species.

There are many habitats here that can be used by bats – with caves aplenty for use in the winter and during breeding seasons. In addition, bat populations in cities are becoming increasingly common — they're found roosting under bridges, in vacant buildings, and in the trees of parks. In cities such as Lisbon, there are thousands of bats of various species, and at dusk, Castelo de S. Jorge sees several species of bats flying over the walls, towers, barbican and moat.

Apparently, the most common bat here in Portugal is the little brown bat or mouse-eared bat (Myotis), followed by the common pipistrelle. Thankfully not found here, the Golden-Crowned Flying Fox, with a wingspan of up to 1.8m, found in the Philippines, is the largest bat species in the world, with individuals weighing up to 1.40k. By comparison, a pipistrelle weighs around a mere 5 grams.

The major threats that occur in Portugal

Disturbance is one of the threats that exist for bats. People involved in outdoor activities unwittingly disturb them, and shepherds have been known to block the entrance of vertical caves to keep their own animals from falling into them. In accordance with Portuguese law, the entrances of inactive mine galleries are often closed with walls, but some still have open entrances, and efforts are being made to avoid the blocking of the entrances of the galleries used by bats by the mining authorities.

Loss of food

Portugal´s landscape is changing, and traditional land use practices were overall better for the bats. Climate change, habitat loss, declining insect populations, and collisions with wind turbines are all causing a loss of their food source. Being able to eat their own body weight in insects nightly potentially means they are helping foresters and farmers protect their crops.

Myths

Calling them ‘flying rats’, is nothing but a myth, as they aren’t even closely related. Another myth to put fear into young ladies’ minds was that if you went out on your own, bats would fly into your hair – in reality, they probably just had their echolocator focused on a juicy mosquito heading to your neck!

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