How scientists took their cue from bats and invented radar

Radar is a marvelous electrical device that measures the distance of wave-blocking objects by the round-trip time of electromagnetic waves. If you ask who invented radar? In Fink's radar machinery, said, "the invention of radar, can not be attributed exclusively to a particular scientist, is a number of radiological engineers to work hard to study, to be adjusted and become." During the war, the Massachusetts Institute of Technology (MIT) had five hundred scientists and engineers working on radar. It is amazing that in nature you find radar that God has prepared for a particular animal. In the January 1947 issue of the British journal Endeavor, the scientist B. Vesey-Fitzgerald published a very interesting text explaining to us how a bat guides itself in the darkness and never touches a wall, no matter how dark or how narrow it is. How does it know if there is an obstacle in front of it? On this matter, two American biologists, Griffin and Carambola, have proved in 1940 that bats are able to avoid collisions by means of a kind of natural radar, but it is a sound wave instead of an electromagnetic wave, which is exactly the same in principle. From the bat's mouth to send a very high frequency sound waves, more than the range of human hearing outside, two scientists by a special power equipment, in the bat flight, it will send high-frequency sound waves recorded out. This kind of sound wave touches the wall, must fold back, its eardrums will be able to distinguish the distance of the obstacle, and fly to the appropriate direction. Bat transmitting sound waves are like radar, are very short time apart and very regular, and each bat, has its own inherent frequency, so that bats can distinguish their own sound, not to disturb. Because of this reason, the bat flight, often open mouth, if you close its mouth, it will lose the role of command, if you plug its ears, it will hit the wall, can not fly. This is an interesting experiment that breaks its secret.

Flying "live radar"

Bats are good at flying through the air, making circular turns, braking and changing speeds quickly. White dogs, hidden in caves,

tree caves or eaves in the gap; dusk and night, flying in the air, prey on mosquitoes, flies, moths and other insects. Bats prey on a large number of pests that are beneficial to people and deserve

to be protected.

By summer, the female bat gives birth to a fairly fully developed young. The newborn is covered in downy fur and hangs firmly by its claws from the mother's chest to suckle milk,

and does not fall off while the mother is flying.

Bats have two wings for flying, which are not the same structure as bird wings and are made up of membranes of skin linked between the forelimbs, hind limbs, and tail. The second,

third, fourth, and fifth fingers of the forelimbs are especially long, and are adapted to support the dermatome; the first fingers are small, and grow outside the dermatome, with hooked claws at their ends. The hind limbs are short, with feet extending outside the dermatome, five toes,

with hooked claws at the ends of the toes. When resting, the claws are often used to hang the body upside down in a burrow or under the eaves of a house. When crawling in trees or on the ground, it relies on the first finger and foot to grasp rough objects

to move forward. Bats have light bones and a sternum with a protrusion similar to the keel of a bird, on which grow the muscles that move the wings.

The bat has a wide mouth with tiny, sharp teeth suitable for feeding on flying insects. It has weak eyesight, but a keen sense of hearing and touch. Some

Experiments have proved that bats rely mainly on their sense of hearing to detect insects. While flying, bats are able to produce ultrasonic waves in their throat, which are emitted through their mouth. When

the ultrasound encounters an insect or an obstacle and reflects back, the bat is able to receive it with its ears and determine whether the target of detection is an insect or an obstacle, and how far away it is

. This way of detecting a target is often called "echolocation". The signals that bats send out when feeding, orienting, and flying are made up of

ultrasonic phonemes that resemble speech phonemes. Bats must receive echoes and analyze the acoustic characteristics of such echoes in terms of amplitude, frequency, signal spacing, etc.

before they can decide what action to take next.

Bats that rely on echoes for ranging and localization emit only a simple sound signal, which usually consists of one or two phonemes repeated at regular intervals

. When the bat is flying, the signal is bounced back by an object, creating an echo that has different sound characteristics depending on the nature of the object. The bat

then decides on the nature and location of the object after analyzing the sound characteristics of the echoes such as frequency, pitch, and sound interval.

Different parts of the bat brain intercept different components of the echo signal. Some neurons in the bat brain are sensitive to echo frequency, while others are sensitive to the time interval between two

consecutive sounds. The ****synchronization of the various parts of the brain allows bats to make judgments about the traits of reflected objects. The flexibility and accuracy with which bats use echolocation to catch

insects is phenomenal. It has been calculated that bats can capture an insect in a matter of seconds and a dozen

insects a minute. At the same time, bats are amazingly resistant to interference, detecting a particular sound from the clutter of noise-filled echoes, and then quickly

analyzing and identifying that sound to differentiate whether the object reflecting the sound wave is an insect or a rock, or, more precisely, to decide whether it's an edible or inedible insect.

When 20,000 bats live in the same cave, they also don't interfere with each other because there are too many ultrasounds in the space. The accuracy of bat echolocation and the ability to resist

jamming are important references for people to study the improvement of radar's sensitivity and anti-jamming ability