Ancient humans crossed a swamp, not a bridge, to reach America
- Geologists conducted research revealing the Bering Land Bridge was a wet ecosystem from 36,000 to 11,000 years ago.
- Findings included evidence of freshwater lakes, river channels, and DNA from species like mammoths.
- This research reshapes understanding of ancient species migration patterns and habitat diversity.
During the last Ice Age, a landmass connected modern-day Siberia and Alaska, allowing for migration across the Bering Sea. Until recently, this area was thought to resemble an arid landscape similar to the current topography of both regions. However, new findings suggest that the Bering Land Bridge was more like a swampy ecosystem from 36,000 to 11,000 years ago. Research led by Jenna Hill of the U.S. Geological Survey revealed complex waterways that could have served as both barriers and pathways for species. This potential habitat underscores the nuanced role that topography plays in migration and speciation. In December 2023, researchers conducted sonar readings and analyzed sediment cores from the sea floor to reconstruct the prehistoric landscape. Contrary to expectations, they discovered an abundance of small lakes and river channels rather than large, isolated bodies of freshwater. Their findings also returned evidence of woody trees, as well as fossils indicating widespread freshwater—all suggesting a robust ecosystem that existed when the land bridge was operational. The implications of this study are significant. While a boggy landscape may seem like it would hinder the movement of larger animals, the research indicates that pathways likely existed for species like mammoths to traverse the region. DNA evidence collected suggests that these grazers were able to navigate though marshy terrain, further complicating prior assumptions about species migration routes during the last Ice Age. The new understanding urges scientists to reconsider both how ancient animals migrated and how environments interact with species spread. In summary, the Bering Land Bridge provided not merely a passage for migration but supported ecological diversity that could have influenced the survival and distribution of multiple species. This research emphasizes that our views on ancient ecosystems need to evolve as we uncover evidence of former landscapes, leading to a deeper understanding of how climate and geography interact in shaping biodiversity.