How do homing pigeons tell the direction?

Question 1: How can pigeons tell the direction? The authoritative explanations are acute sense of smell and detecting magnetic field. Now, after decades of investigation and research, scientists have confirmed that the pigeon's upper beak does have a unit cell that can induce magnetic field, and it is this organ that guides the pigeon's flight. The report of this study was published in Nature on1October 25th, 165438.

keep a secret

Recently, after a series of detailed behavioral experiments in the laboratory, scientists announced that they had clearly proved for the first time that pigeons have magnetic sensing ability, just like a simple magnetic compass, which uses the earth's magnetic field to navigate pigeons and perhaps other birds and turtles. Dr. Kaddoura Nora, a biologist at the University of North Carolina in the United States, said at Chapel Hill Art College: "There are two main theories about the ability of pigeons to find their way home: one is that pigeons find their way home by smell; The other is that they have a magnetic map in their brains. Our work strongly supports the latter theory. Of course, this theory needs further proof. "

This research on pigeons is a doctoral research project in Nora, New Zealand. The report of this study was published in Nature on1October 25th, 165438. The other authors of the research report are Dr. Michael Walker, Dr. Michael Davidson and Dr. Martin Weil from the University of Auckland, New Zealand.

Dr Kenneth Roman, a famous professor of biology at the University of North Carolina, said: "This is a fascinating study. In this study, Nora trained some homing pigeons that can respond to magnetic fields. This is an important news in biology, because some people have done many experiments on 10 in the past few years, but they all failed. Nora was the first person to find an effective method. "

The experiment was carried out like this.

Nora said that in the experiment, if pigeons accurately find two platforms in a room similar to a tunnel, they will get food rewards. Under normal circumstances, they will climb to either platform to find food. But when horseshoe magnets are placed above and below the food platform to induce them, these pigeons will find food accurately. The accuracy rate reached 75%. This is much more accurate than their random search for food.

Knowing that pigeons can respond to magnetic fields, Nora's next step is to find out where the magnetic field receptors are in pigeons.

They first tied a small strong magnet to the pigeons' beaks, and as a result, these pigeons found the wrong platform more than half the time. When they tied a piece of brass with the same weight but no magnetic force to the pigeon's mouth, the result had no effect. Then, they locally anesthetized the pigeon's upper beak and cut off the trigeminal nerve, and found that all these would weaken the pigeon's ability to detect magnetic fields. But when the olfactory nerve that transmits olfactory information is cut off, it will not weaken the pigeon's ability to perceive magnetic field. Through these experiments, Nora thinks that the pigeon's magnetic field perception ability lies in the nose area. Nora said: "In the experiment, we know that pigeons have the ability to recognize magnetic fields. However, this ability can also be weakened in various ways. Now we can say that the pigeon's magnetic field perception ability is in the nose area. "

Maybe there is more than one answer.

Nora's research results are very convincing, that is, pigeons find their way by the earth's magnetic field. Other research results also show that pigeons may know their way in many ways, because other scientists have made other discoveries. For example, British researchers published a research report in February this year, claiming to have solved the mystery of pigeons identifying their way home. They think that the secret of pigeons finding their way home is actually very simple and direct. Like other birds, they often fly along artificial shipping and aviation signs such as roads, railways and canals, and finally reach their destinations.

The study was conducted by a zoologist at Oxford University. They studied the homing of pigeons in 65,438+00 years. In the last year and a half, they tracked the flight path of birds with the most advanced global positioning technology, with an error of 1 ~ 4 meters. Researchers in the Department of Zoology of Oxford University said that after more than 65,438+00 years of international research, it was really surprising to find that pigeons did not seem to rely on their innate instinct to tell directions, but flew according to the road system. If it is a long-distance flight or the first flight, pigeons will use their directional nature to identify their orientation according to the sun and stars. But as long as it flies once, the pigeon will fly back according to the familiar route, much like people driving or walking home after work. The researcher said: "Some people may think this matter is trivial, but for us ... >>"

Question 2: Excuse me, what does a homing pigeon rely on to tell its direction? Pigeons know their direction not by their eyes, but by the earth's magnetic field.

Some people regard pigeons as semiconductors with a resistance of1000Ω. When it flaps its wings in the earth's magnetic field, the wings cut the magnetic field lines, thus generating induced electromotive force (i.e. induced voltage) between the wings. Pigeons fly in different directions, because they cut the magnetic field lines in different directions, so they can distinguish the directions. However, experiments show that the additional magnetic field does not affect the flight in sunny days. This shows that geomagnetism is not its only compass. It turns out that pigeons can detect polarized light, and on sunny days, they can choose the flight direction according to the position of the sun, so the movement of the sun is corrected by the biological clock in the body. It must be pointed out that when the current flows counterclockwise, it can fly home whether it is sunny or cloudy.

Question 3: How do pigeons tell the direction? 1, pigeons are also divided into meat pigeons and carrier pigeons.

2. homing pigeons don't know the direction by their eyes, but by the earth's magnetic field.

Geomagnetism is not its only compass. In fact, pigeons can choose the flight direction according to the position of the sun on a sunny day, and the internal biological clock also corrects the movement of the sun accordingly. However, when encountering thunderstorms or TV towers, homing pigeons may be unable to distinguish the direction of the earth's magnetic field because of the interference of the geomagnetic field in these areas, resulting in getting lost.

Question 4: How did pigeons find their way in ancient times? Ancient pigeons, like modern pigeons, distinguish the north from the south by the earth's magnetic field. What you should ask is the carrier pigeon handle. In ancient times, homing pigeons set certain reference objects for their identification during training, so as to determine the place to deliver letters. Carrier pigeons will be grouped in training, and different groups will fly in the same direction to find ground reference objects.

PS: Pigeons' eyesight is ten times better, and they can distinguish signs of ground maintenance.

Question 5: How do pigeons know the route and direction? According to research, pigeons can determine their own direction according to the positions of the sun, moon and stars. Some people say that pigeons can tell their direction by their sense of smell, but now the mainstream view is that pigeons have organs that can feel the changes of the earth's magnetic field, and their accuracy is as accurate as a compass. Scientists have confirmed that pigeons have magnetic sensing ability, just like a magnetic compass, that is, pigeons can navigate by using the earth's magnetic field. The magnitude and direction of the magnetic force of the earth's magnetic field are different, which actually forms geomagnetic signposts. Pigeons use this signpost to fly accurately. With accurate navigation, pigeons can of course easily return to their nests without getting lost.

Question 6: How can pigeons tell the direction? The feathers on the wings can sense the airflow and can be distinguished by the difference of airflow. ..

Question 7: How do pigeons tell their directions? Magnetic force theory. Later, scientists tried to explain the pigeon's directional ability with magnetic theory. In a vast area, the earth's magnetic field changes with different places and directions. So as to provide position information for pigeons. Magnetic field strength, magnetic dip angle and magnetic declination angle can form a highly non-orthogonal network with each other. These components are almost constant in an area of several hundred kilometers. But it changes gradually all over the surface of the earth. The gradient network formed by these changing components is called navigation chart and can be used for orientation. Experiments in recent years have confirmed the existence of magnetic navigation. When the artificial magnet with specific polarity is added to the head of the pigeon bomb, the pigeon's flight cannot be oriented correctly; Whenever the solar proton activity is intense, the earth's magnetic field is disturbed, and the homing rate of pigeons is greatly reduced. In addition, the preliminary research results show that there is a needle magnet with a length of about 0. 1 micron in the forebrain under the skull of pigeons. They think pigeons can use geomagnetism to determine their own direction. They have the ability to detect the four basic points of the earth and can receive the changing signals fed back by the magnetic field. However, some people think that these changes are extremely subtle, and whether pigeons can feel these subtle changes needs full proof.