who first invented the Bering strait theory ?

Answer 1

Franz Boaz in 1922

Answer 2

If you are referring to the belief that the first Native Americans arrived by a land bridge (over the Bering Strait), connecting present-day Alaska and Eastern Siberia, it is not a theory. A "land bridge" is an area or isthmus that connects two land masses that are most of the time separated by water. When water levels drop significantly, areas of continental shelf are exposed as dry land. The most recent land bridge occurred 20,000 years ago (in the Upper Pleistocene or "PLY-sto-seen" Ice Ages) when worldwide sea levels were about 120 meters below today's levels. By 10,000 years ago, it was still 20 meters below current levels. So, because of this, plants and animals and even humans were able to cross from Eurasia to the Americas. The idea of land bridges is the only cause scientists can find when finding fossils of plants and animals not normally seen in certain continents (like plants normally found in Africa were found in the Americas).
Another reason why land bridges can exist is global warming causing lower sea levels, and tectonic plate movements (how earthquakes are detected. These usually fit together with a narrow opening between them called a "fault line", and when the plates move significantly, the fault line expands and causes earthquakes. California has the San Andreas Fault running north and south through it, and that is why if the BIG quake ever comes, California could be an island because it would be split in half from the rest of the country). A study of geology will show how these things occur.

Answer 3

http://www.native-languages.org/bering.htm