Changes in sea level allowed animals to migrate to the Americas.

Evidence

The sea between Russia and Alaska (the Bering Strait) became a wide and easily passable land bridge. Animals – bison and reindeer among them – moved across to the American side, and the humans hunting them followed. — Neil MacGregor, A History of the World in 100 Objects, 122

Categorization

• corroborated: 2 independent passages support this claim — Neil MacGregor, A History of the World in 100 Objects, 122
• XREF: connects to: Climate changes facilitated human migration into the Americas. — Neil MacGregor, A History of the World in 100 Objects, 122