Ice-age sea-level declines can expose land bridges between continents that were previously submerged.
Notes on verification
Well-established geological/paleoclimate phenomenon confirmed by multiple independent sources including NPS, Wikipedia, and peer-reviewed research (e.g., Bering Land Bridge studies). [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.735 clusters=2 claim_tier=everyday]
Sources
- Ice Age - Definition & Timeline (seed:history_and_archaeology)
- https://www.nps.gov/articles/aps-v12-i2-c8.htm (corroboration)
- https://research.princeton.edu/news/bering-land-bridge-formed-surprisingly-late-during-last-ice-age (corroboration)