They stalk and look for the stragglers, weak, or wounded. Any type of limp, stagger, or hesitation makes you a prime target. Children should always walk in front, not behind.
On the otherhand, they do not like humans and will avoid contact unless they are very hungry.
It is odd, but for years the Oklahoma Department of Wildlife Conservation denied that there were any cougars in Oklahoma. And when there was one causing problems in the Southwestern part of the State, they had to call a private naturalist to capture and deal with it. He put it in his private zoo.