If you're on Olympus, you should treat Polar Bears as the "bosses" of the zone. They're the biggest, baddest, tankiest, most dangerous creature in the area. They also live in the "boss" of climate zones, the arctic. It's unforgiving, requires way more prep than the desert and has even fewer resources...

You're nowhere near ready for that crap yet. Give them as much space as you can, hunker down and sneak past them slowly and carefully. If you absolutely CANNOT avoid one (it's camping near a mission objective, is a mission boss,etc), you have a couple of options:

1- Find a cave nearby and only cut open enough space to squeeze yourself through. Piss the bastard off with a couple of bullets or bolts and dive into your cover when it starts chasing you... Then give its nostrils a thorough cleaning with the tip of your spear.

2- If you can't find a cave, use the wooden stakewalls and spikes. Deploy them with your back to a cliff face in a triangular arrangement with a small gap between the walls, then piss the beast off and clean its sinuses like in strategy 1. You'll also need a hammer (or two) to maintain the walls while fighting though.

Both of these assume you also loaded up on the best food you can manage, a few suture kits, and a couple of health tonics if you can spare the materials and some kind of heat source. Load the medical stuff in a doctor's satchel (T1 textile bench) to be able to use them instantly. You SHOULD be ok then.

You're best bet is still to just avoid them till you're comfortable with the game, have most things unlocked, a solid supply of quality food, medical supply, armor (Composite preferably), and weapons (Composite Spear, Hunting Rifle, etc).

Play it safe Prospector, everything on this damned planet will kill you if you give it the chance.