Black bear study shows eating human food helps and hurts DURANGO, Colo. — Black bears that eat human foods from trash cans have higher reproductive rates than those living on natural foods, according to a study by Colorado researchers. The study by researchers with Colorado Parks and Wildlife also found bears that eat human food don’t survive as long as those left to the wild. The bears have been fitted with collars that track their location, helping researchers determine how the animals behave. The researchers use hair samples to find out how much processed human food the bears had been eating.