Grizzly bears go from being vegetarian to carnivorous depending on what's available. How long were these scientists watching? I've done a lot of fieldwork in grizzly country over the past 40 years and when wild raspberries are at their peak, that is all they eat for ~3 wks ... the better to put on fat for hibernation. You ain't seen nothing until you've come upon a knee-high pile of steaming grizzly sh!t full of raspberry seeds (hint ... start walking backwards the way you came from). Other times, like late winter/early spring, the turds contain only fur and bones. And some years there are better berry crops depending on spring rainfall and absence of killing frosts during flowering.