An individual who moves from one geographical area to another is called a migrant, a situation that entails a change in customs and a process of readjustment to new circumstances.
The concept of migrant can also be applied to a member of an animal species that changes its habitat. In the first case, that is, with respect to human realities, the science in charge of its study is called demography; in the second case, that is, with respect to the behavior of animal species, the science to study it is ecology.
Although there have been migrations since the appearance of human beings on the face of the earth, it is possible to speak of processes of large migratory flows associated with major events in the history of mankind: about nine thousand years ago and during the neolithic revolution which constituted the development of agriculture, there were large displacements in Africa, Asia, Europe and America.
the formation of the great empires of antiquity brought about the formation of colonies with the consequent human flow; conflicts between fiefdoms during the feudal regime led to human migration for war purposes; the colonizing processes carried out during the modern age (as for example North America) they were also mobilizers of great human masses; the industrial revolution resulted in the transfer of population from rural to urban areas; the great European emigration of the first half of the 20th century it brought large numbers of poor Europeans to many countries in America.
At present, a new large-scale migratory process is underway that began in the mid-twentieth century and that consists of the existence of a large number of migrants leaving peripheral countries and moving to central countries. This phenomenon has worried the authorities of the affected countries, many of them belonging to the European Union.
