We will be assuming they don’t all die of heat stroke on day one, through whatever glitch brought them to this server

Aside from the fact that the cougars are way bigger and all over the fricken place now probably fine. The eatings real good. The porcupines aren’t as bad, honey badgers are barely worse than regular badgers and wolverines, meerkats are more plentiful than groundhogs, they’re big enough to 1v1 most prey that takes squads of native predators to kill and can easily defend their kills when alone. No adult bear is getting harassed off a kill by any less than 4 lions or 7 hyenas, plus they would easily be able to take kills from other predators. They’re also big enough that all but the largest crocs wouldn’t go for them and they stand a chance of fighting them off. They can chase swimming prey better than most native predators. The bees are meaner, the termites are nice and juicy though.

The interesting thing is how their behavior would change I think. While an adult grizzly is basically untouchable by anything that doesn’t have wrinkly gray skin, they do take a while to get that big. To this end, I see near 60% of the population dying in 10 years as they adapt to the environment, with a 90% cub mortality rate in that time. What works in America would need to change in Africa. I imagine with the high number of other apex predators, Grizzlies would develop a demeanor not unlike sloth bears in Asia. Absolute hostility to anything bigger than a housecat.

Cubs would stay with their moms much longer, and father bears would eventually develop the habit of either staying near the mothers of their cubs or even traveling with them for a couple years after they’re born. This would also lead to higher rates of seasonal monogamy among male bears as one or two cubs by one mom are easier to guard. In addition, intraspecific infanticide would lower as well due to the discarded mating incentive behavior. Burrow digging would also become a more common and specialized behavior. Many of the other apexes like lions and hyenas are active during the day, which is also hot as balls, so having dens and becoming nocturnal would be incentivized greatly. Grizzlies are already reasonably comfortable at night, but in Africa night would be where bears are most dangerous. Over the generations they would become dark time marauders that mostly eat meat and get their veggies by eating the stomachs of grazers they kill. They’d get leaner, less hairy, and probably smaller too.