Orientation in migration of animals

Normally millions of animals make long journeys in the fall and spring, hundreds or thousands of kilometers according to the species. These journeys raise many questions: How do they know their destination? And the process? To answer them, it must be taken into account that animals use three types of information: genetic, terrestrial and heavenly. And have activated compasses and organic watches by internal sensors.

First we have genetics. As an example, let’s look at birds that migrate from Europe to a defined destination, but in general not unique. For example in the south, southeast and southwest. It turned out that birds born in captivity, from the three routes, retained the genetic information from their parents. But if they cross, the new generation opts for intermediate routes. For less complex animals, such as shellfish, ants, etc., the choice of a route of body orientation and movement direction determines. But something important is; How far is fate? The central nervous system of these animals offers speed and time and, from this data, the distance traveled. The most complex animals have organic watches and compasses to measure length and latitude. Latitude is, for example, determined from the position and height of the stars or from the slope of the magnetic field. The length is more difficult. Even the man, before the chronometers (today GPS) appeared in the second half of the 18th, made large measurement errors. Animals have what we can call organic chronometers. They are sensitive to the position changes that generate signals. Something similar to what happens to people with GPS. With these signs, the brain (or a simpler system) makes the right corrections to eliminate errors in movements.

Under the terrestrial references, in addition to the magnetic compass that has a large number of species that do not distinguish between the North-South effect, there are other biological compasses that are sensitive to the movement that produces water, wind and other environmental phenomena. For example, the mechanical effect of sea breams and waves controls the migration of lobsters. On the other hand, the heavenly references are: the sun, the moon and the stars. A solar compass has almost all animals. For example, there are many simple animals that use and stop the polarization of light when there are clouds. More complex is the relocation of birds that travel during the day and night. They have the problem that comes from the height of the sun on the Horizon and his Azimut. To solve it, they synchronize its internal biological clock with the external plot through the information it offers, including the daily cycle of darkness light. Finally the Stars watch, which seems to be taught. We have seen a brief introduction to an exceptional navigation system.