Study: U.S.-Mexico Border Endangers Bear Migration

01/03/2012 04:41 pm ET | Updated Mar 04, 2012

As the debate over the U.S.-Mexico border fence continues to roll on, a group of biologists claim that besides keeping undocumented immigrants from crossing between the two countries the fence also blocks black bears in Arizona from migrating to Mexico and back.

Already under stress from urban build-up, the black bear migration in southern Arizona's Sky Island mountain ranges is further threatened by the border fence, a study in Biological Conservation concluded.