"A rare light type beast that is resting, we are going to walk silently away from here and do absolutely nothing to bother it. No attacking beasts. No making noise. Now making camp. No food. Nothing." Clark calmly explained what the giant mossy sloth was to the group.
It was enough that they all could feel the weight of the situation they had walked in to. Whether they did or did not stay in the area, they were currently in a terrifying situation.
If this beast was to wake up and find fault with anything that they did, they would lose that fight. Light type beasts were on the rarer side because of their unique skills and the fact that there were just more of certain beasts in general. Earth and water took the most common beast species typing there was.
Creation is hard, cheer me up!