A bat gets caught in your hair, its claws cling to your locks, the animal struggles to free itself. You don’t dare put your hands there, for fear of getting bitten. You scream in terror. Don’t panic, you will wake up soon. Except in nightmares, bats do not get tangled in hair. Bats are indeed equipped with such a precise echolocation system that they can circle around a single hair without touching it. All the explanations about the super power possessed by these small nocturnal mammals.
Can bats get tangled in our hair?
No. This belief dates from a time when, to prevent young girls from going out in the evening, it was claimed that bats would get caught in their hairstyles. If this fearful animal approaches (unintentionally) humans, it is generally because a mosquito is lurking nearby. Not only are bats not interested in humans, they are afraid of them. Bats display such precision in flight that they are able to avoid obstacles such as hair. Their secret sauce? The excellent perception of the environment gives them echolocation, a system that allows bats to orient themselves in the dark and detect prey, including the tiniest insects. Note that this ability is found in more than 1000 animal species, notably small nocturnal mammals and all toothed cetaceans. Insectivorous bats have this, but frugivores (eating fruit) and nectarivores (eating nectar) rely more on their sight and smell to move around and find food.
Bat: how does echolocation work?
To put it simply, echolocation (we also use the English term echolocation) works in this way: an animal emits a sound wave which ricochets against an object and returns an echo giving information on the size of this object and the distance at which it turns out that. These ultrasonic signals are called ultrasound. For comparison, the ultrasound emitted by European species of bats (located between 10 and 110 kHertz) escapes the human ear, which does not perceive sounds above 18 kHz. Echolocation methods use throat vibrations or wing beats. In bats, ultrasound comes from the larynx, so we speak of laryngeal echolocation. To be effective when moving quickly or actively hunting prey, you must broadcast high-frequency sounds in bursts and instantly analyze the echoes that form.
Why don’t bats get caught in our hair?
When we talk about the notion of echolocation, we inevitably think of bats. Here are the 2 characteristics that make them experts in this field:
We have seen that the bat practices laryngeal echolocation. To do this, they contract the muscles of their highly developed larynx to produce sounds with a frequency higher than the threshold of perception of the human ear. Depending on the type of bat, the emission of ultrasound takes place through the open mouth, through the nostrils or through a nasal leaf, a set of complex folds at the level of the snout which is found for example in bats. vampire mice (see below). This sensory system requires a lot of energy from animals because to be effective, it requires continuous operation. For example, if the prey is constantly moving, bats must emit clicks continuously, sometimes up to 190 per second;
Reception of echoes
The sound received in return passes through the ears of the ears which are shaped like horns and have various shapes. It then passes through the ear canal to the tympanic membrane. There, it beats the membrane which transmits to the 3 ossicles characteristic of mammals which will in turn transmit to the inner ear including the cochlea. This hollow, spiral-shaped organ contains sensitive cells that translate vibrations into nerve impulses that then go to the brain. The latter will then decode the distance of the obstacle which returned the ultrasound, the speed, the movements (of prey for example) and the direction. Namely, the 2 ears move independently, providing 3D interpretation and some species can change the shape of their ears to more accurately capture incoming signals.
Can a bat bite?
Bats do not seek to approach humans or attack them. They may only bite if they feel threatened or are disturbed. The rare cases of bites most often occur when handling the animal or disturbing it in its habitat. Resting on the ground is not a bat habit, so an individual found on the ground is likely to be sick or injured. You should never touch him, even when dead. If the bat is alive, it may attempt to bite to defend itself. If, despite everything, you are bitten by a bat or if you have come into contact with its saliva through a mucous membrane (eye, nose, mouth), you should clean the affected area thoroughly with soap and rinse it thoroughly. and disinfect it using an antiseptic solution. You must then consult a health professional who will consider the appropriate measures to take.
Do bats transmit rabies?
Yes, bats can transmit rabies. They are among the potential carriers of the rabies virus which they can inoculate to other animals and humans through their saliva in the event of a bite or contact with mucous membranes or open wounds. In France, only a small minority of bat species (2 out of the 36 species recorded) have been identified as carrying the virus. Rabies is an infection of the nervous system (encephalitis) that disrupts neuronal activity. The incubation time of the disease is long enough to allow treatment by vaccination before the first symptoms appear. However, without treatment before symptoms appear, the disease is systematically fatal. In 2019, a case of rabies likely transmitted by a bat and confirmed by the Pasteur Institute caused the death of a patient in New Aquitaine. Mainland France, like most European countries, remains mainly exposed to rabies through the illegal introduction of contaminated animals (mainly from Asia and Africa) or by travelers becoming infected in areas where rabies is prevalent. virus.
Do bats suck blood?
Of the 1,400 species of bats known to date in the world, only 3 feed on the blood of animals and therefore follow a so-called “hematophagous” diet. Referred to as vampire bats, they live only in South America. In France, all species are insectivorous and as such constitute real natural insecticides which get rid of mosquitoes, for example. The 3 species of vampire bats that feed on the blood of animals are:
The common vampire (Desmodus rotundus). Its coat is brownish on the back and lighter on the belly. Its wings are blackish with a gray or white and brown underside. Its nose is surrounded by dermal growths forming ridges above the nostrils (nasal sheet). Its short muzzle accommodates long canines and upper incisors with a cutting edge. Desmodus rotundus is about 9 cm long and weighs up to 40 g; The hairy-footed vampire (Diphylla ecaudata). This species resembles the common vampire but smaller: it measures between 7 and 9 cm and weighs 30 to 40 g. Its coat sports shades of reddish brown to charcoal brown. Of the 3 vampires, he is the one with the most teeth (26); The white-winged vampire (Diaemus youngi). This third species, rarer, also resembles the common vampire but smaller. Its size is 8 cm and its weight is 35 g. Diaemus youngi is best recognized by its brownish coat which contrasts with the white bordering its wings and the tip of its patagium.