Migration

I

Introduction

Migration, movement of people, especially of whole groups, from one place, region, or country to another, particularly with the intention of making permanent settlement in a new location. Human beings have migrated since their emergence as a species. Their original differentiation into ethnic groups appears to have been a result of the isolated development of separate groups of people who migrated from a central point of origin, perhaps in Africa or Central Asia. Even in the Stone Age, however, this isolation was not complete, for migrations resulted in a complicated pattern of blood relationships through widely separated groups.

II

Movement of Peoples

In the more recent past the movement and countermovement of peoples have led to accelerated mixing of stocks and mutual infusion of physical characteristics. Perhaps more important than the transmission of physical characteristics has been the transmission of cultural characteristics. The diffusion of cultures, including tools, habits, ideas, and forms of social organization, was a prerequisite for the development of modern civilization, which would probably have taken place much more slowly if people had not moved from place to place. For instance, use of the horse was introduced into the Middle East by the Asian invaders of ancient Sumer and later spread to Europe and the Americas. Even important historical events can be linked to distant migrations; the downfall of the Roman Empire in the 3rd to the 6th centuries ad, for example, was probably hastened by migrations following the building of the Great Wall of China, which prevented the eastward expansion of Central Asian peoples, thus turning them in the direction of Europe.

A

Causes

A group of people may migrate in response to the lure of a more favourable region or because of some adverse condition or combination of conditions in the home environment. Most historians believe that non-nomadic peoples are disinclined to leave the places to which they are accustomed, and that most historic and prehistoric migrations were stimulated by a deterioration of home conditions. This belief is supported by records of the events preceding most major migrations.

The specific stimuli for migrations may be either natural or social causes. Among the natural causes are changes in climate, stimulating a search for warmer or colder lands; volcanic eruptions or floods that render sizeable areas uninhabitable; and periodic fluctuations in rainfall. Social causes, however, are generally considered to have prompted many more migrations than natural causes. Examples of such social causes are an inadequate food supply caused by population increase; defeat in war, as in the forced migration of Germans from those parts of Germany absorbed by Poland after the end of World War II in 1945; a desire for material gain, as in the 13th-century invasion of the wealthy cities of western Asia by Turkish peoples; and the search for religious or political freedom, as in the migrations of the Huguenots, Jews, Puritans, the Society of Friends or Quakers, and other groups to North America. Theories of migration are discussed in Migration (geography).

B

Choice of Routes

Throughout history, the choice of migratory routes has been influenced by the tendency of groups to seek a type of environment similar to the one they left, and by the existence of natural barriers, such as large rivers, seas, deserts, and mountain ranges. The belts of steppe, forest, and arctic tundra that stretch from central Europe to the Pacific Ocean have been a constant encouragement to east-west migration of groups situated along their length. On the other hand, migrations from tropical to temperate areas, or from temperate to tropical areas, have been rare. The desert regions of the Sahara in northern Africa separated the African from the Mediterranean peoples and inhibited the diffusion southward of Egyptian and other cultures, and the Himalaya mountain system of southern Asia cut off approaches to the subcontinent of India except from its eastern and western borders. As a consequence of these and similar barriers, certain mountain passes and land bridges became traditional migratory routes. The Sinai Peninsula in north-eastern Egypt, bounded on the east by the Arabian Peninsula, linked Africa and Asia; the Bosporus region of north-western Turkey connected Europe and the Middle East; the Daryal Gorge in the Caucasus Mountains of Georgia, Armenia, Azerbaijan, and south-western Russia was used by the successive peoples that poured out of the European steppes into the Middle East; and the broad valley between the Altai Mountains and the Tian Mountains of Central Asia provided the route by which Central Asian peoples swept westward.