Wow lots of bipedalism questions lately, here's a good list of the theories on why humans did it, pick your favorite and adapt that!
I like bears in particular for a couple of reasons:
-They occasionally use bipedalism now to explore their environment and acquire food (which was true of primates before we evolved)
-Bear species are super creative with their diet and if you find them a great food source that requires more bipedalism I could realistically see them evolving for it. Recently in North America they've gone from Short-Faced Bears (extinct scavenger obligate carnivores) -> Grizzly Bears (omnivore that prefers meat) -> Black Bears (more populous omnivore and probably actively knocking over your garbage can). Not to mention Polar Bears and Pandas, the latter of which is frankly an abomination of what species should be able to evolve to do.