The useful question is what changes for users, developers or buyers, and whether the announcement stays industry context or becomes something people can actually use.

Before the Panamanian land bridge formed about 2.8 million years ago, North and South America were isolated continents with distinct mammal populations. Biologists previously believed the Great American Biotic Interchange (GABI) began only after the isthmus emerged, leading to widespread species exchange and extinctions. However, a new study by UC Berkeley paleontologists reveals that northern mammals had already migrated into southern North America by 10 million years ago, creating a gradual mixing period before the land bridge fully connected the continents.

The research, led by UC Berkeley’s Jack Tseng, analyzed fossil records from Mexico and found that larger mammals from northern North America adapted to dry conditions and diversified in Mexico between 10 and 7 million years ago. This period served as a 'holding pen,' allowing smaller mammals like raccoon relatives and rodents to later move into South America via island hopping or vegetation rafts. Only sloths successfully migrated from south to north during this time, with the full interchange accelerating around 3 million years ago when the land bridge formed.

The study challenges earlier geological claims that a land bridge existed as far back as 15 million years, arguing that fossil evidence does not support such an early connection. Instead, the findings suggest that climatic and ecological factors, rather than a physical bridge, initially limited mammal movement. The interchange ultimately reshaped ecosystems, with North American placental mammals outcompeting South American marsupials, which have slower reproductive strategies.

The research team, including collaborators from Mexico and the Natural History Museum of Los Angeles County, plans to expand the fossil record by incorporating more South American specimens to refine migration timelines. The work, funded by the National Science Foundation, underscores the complexity of prehistoric species exchange and its lasting impact on biodiversity patterns observed today.