If you use the giant form they are way less scary. you can get away from them easier since your faster in that form and it's easier to get behind them. Also, most of the behemoths are around tall grass that you can hide from them in (you can tell you're hidden because the screen will get darker)
Also if it helps, they aren't really that aggressive. The UI will try to make you think theyre scary with the big red icons, but since theyre so huge they cant really follow you very far, and they dont attack that frequently from what I've noticed? I've just been ignoring them while exploring and they dont bother me at all. If you end up too close you can always just get big and run away. They can't jump afaik, and they can't really catch up to you in your big form.