The big problem for endangered orcas? Inbreeding

This Sept. 2015, photo provided by NOAA Fisheries shows an aerial view of adult female Southern Resident killer whale (J16) swimming with her calf (J50). New research suggests that inbreeding may be a key reason that the Pacific Northwest's endangered population of killer whales has failed to recover despite decades of conservation efforts. The so-called "southern resident" population of orcas stands at 73 whales. That's just two more than in 1971, after scores of the whales were captured for display in marine theme parks around the world. (NOAA Fisheries/Vancouver Aquarium via AP, File)