South America was detached from other landforms, leading to the isolation of its mammals—or so biologists thought. IB professor Jack Tseng, former IB undergrad Leah Kahn, former visiting postdoctoral scholar Adolfo Pacheco-Castro, and collaborators at the Natural History Museum of Los Angeles and the National Autonomous University of Mexico documented fossil evidence indicating that animals from different latitudes of North and South America intermingled before the formation of the Panamanian land bridge, which linked the two continents. Read the full story in Berkeley News.