Bohme combed through the fossil record of snakeheads worldwide and found two major movements of the fish. Snakeheads first appeared near Pakistan around 50 million years ago. In their first diaspora, around 17.5 million years ago, they began showing up in
Western Europe Western Europe
The countries of western Europe, especially those that are allied with the United States and Canada in the North Atlantic Treaty Organization (established 1949 and usually known as NATO). , Kazakhstan, and southern Siberia. This corresponds to a well-known brief period of warming in the Northern Hemisphere between 25 million and 17 million years ago. It occurred when Antarctica, but not the Arctic, froze, pushing equatorial temperatures northward. Bohme's findings suggest that, along with a Eurasian temperature increase, there was also a boost in summer rainfall there.
Then, 13 million years ago, snakehead fossils disappeared from Europe. About that time, Earth began another long period of cooling, but the change in distribution of snakehead fish indicates that the Eurasian summers were getting dryer as well, Bohme concludes.
The snakehead's second mass exodus came around 8 million years ago. Snakeheads made their way from the Indian subcontinent into China and Africa, where they're found in abundance today. This migration, Bohme found, corresponds with an already recognized intensification of the Asian monsoon system. The warm, humid air from the southern Atlantic and Indian Oceans crashed into the cold, dry air of the then-young Himalayas, causing massive rainfall in Southeast Asia and Africa.
