Or maybe they do, and due to the soil type they slowly come closer to the surface. Could also be that they can't bury them deep enough because they hit permafrost, if they're on the Tundra. But if bears are milling around eating your dead relatives, that's ur-sine to rethink your lifestyle.
Yeah, I know. Without people like you to point it out, who know's what kind of Pandamonium the other posters would get up to?