Mountain lions...once, when I slept in my tent I woke up to two mountain lions fighting right next to it. They were making sound like fighting cats but much louder. Got out of the tent not being sure what was it and saw them may be 20 feet away. Scared them off with noise and they run away.
Coyotes, they will crap to mark the territory. But they might not be sending a message to humans, they might be sending a message to other competitor animals because humans leave food smells behind and attract rodents. I definitely see coyote poop in campsites. One place I camped coyote literally took a big dump on the edge of the campsite while I was in it and I heard it howling. I howl at coyotes sometimes but so far couldn't get them to respond.
