At dusk you can see bats flying in the Netherlands near old bunkers and farms. What is special about these animals is that they use echo sounding (also called echolocation) and polarized light to navigate. But this is not the only thing that makes these animals so special. And what about vampires (bloodsucking bats)? Are these real?
Types of bats and where they live
There are more than 1100 different bat species. Bats can be roughly divided into two groups:
- The little bats; that occur all over the world except for the polar regions and high mountains.
- The big bats that are only found in Africa, Asia, New Guinea and Eastern Australia.
Only small bats occur in the Netherlands. About 15 to 17 different types.
The bat is a mammal
One of the special features of a bat is the fact that it is a flying mammal. The bat is the only mammal that can fly. Usually once a year the female bat gives birth six to ten weeks after mating and sometimes two young. The young are suckled for four weeks.
Bats do not have a steady mate.
The bat; a number of characteristics
- A bat has a stocky stature, short neck, a thick elongated head and a wide slit in the mouth. Size, like body weight, can vary greatly from species to species.
- His ears are very well developed, as is his sense of smell, but he sees very little.
- Its body temperature is 42 degrees Celsius and its heart rate is about 600 beats per minute.
- The bat is completely adapted to flying, but some species can also move very well on foot. The bat has very long fingers that support the fly skin. The fly skin consists of three parts:
- The forefly skin; it runs from the neck to the thumb.
- The finger fly skin; it runs from the fingertips to the hind legs.
- The tail fly skin; this is between the hind legs and the tail.
- The fly skin is very thin and has no hairs. The wingspan of a large bat is up to 1.70 m.
Flying speed of bats
Some bats can reach speeds of 40 to 50 kilometers per hour.
Age of the bat
- Small bats live on average 10 to 15 years at the most.
- Large bats can live up to twenty years.
What do bats eat?
Most bats eat insects, but there are also bats that eat fruits, fruit and / or fish. These bats usually eat as much as their own body weight every day.
Vampires
There are also bats that live on blood. The so-called vampires. These bats make an imperceptible cut (on a cow, horse, human, or other large mammal) and then drink the blood. To ensure that the blood does not clot, the bat injects a substance that mosquitoes also use. It can transmit diseases such as rabies. The vampire needs about 26 liters of blood per year.
Polarized light
It has already been read that a bat cannot see much. Bats use polarized light to navigate, among other things. The bat is the only mammal that can perceive this light.
Echo sounding / sonar
A bat mainly uses echo sounding or sonar to determine its position. This is a special technique for orienting and locating its prey. To do this, the bat sends out sounds with its mouth or nose, which are not perceptible to human hearing and receives the echo (reflection) of this with its ears. (This can be compared to a ball bouncing off a wall). When a bat approaches a prey, the sound waves follow each other faster and faster. Sometimes up to 150 to 200 kilometers per second. The height of the sound waves is sometimes as high as 150,000 hertz (one hertz is one vibration per second) or even higher. It is unknown how a bat knows whether it is dealing with an object or a prey. It is thought to have to do with moving or not moving the object and the smell.
Energy recycling
Bats can push away their wings extra forcefully, because they use ‘energy recycling’. They do this by stretching their tendons and using the stored energy to push their wings away with extra force. This can be compared to the energy that is released when you pull on a rubber band and let it go.
Hibernation
The bats in the Netherlands live on insects. These are (almost) impossible to find in winter. That is why they start looking for a suitable place to hibernate in October. This can be a hollow tree, a cave, a rock crevice, hayloft, cellar, etc. Usually they hang together in large colonies. During hibernation, the body temperature drops from 42 degrees Celsius to 8 to 10 degrees Celsius. Breathing becomes slower and slower and finally the bat only takes one breath every six minutes. The heart rate drops from 600 times per minute to less than 100 times per minute. In March the bat awakens from hibernation.
