Does a bear poop in the woods? Of course it does, and so, apparently, do a whole lot of humans.

Discarded toilet paper is just one of the problems that Rocky Mountain National Park has been dealing with as it leapfrogged ahead of Yellowstone and Yosemite in popularity last year. Its 4.16 million visitors in 2015, an increase of 21 percent from the year before, is behind only Great Smoky Mountains National Park, with 10.71 million guests, and Grand Canyon National Park, with 5.52 million.

“With that increase, we started to see a different behavior in our visitors,” said Kyle Patterson, a Rocky Mountain National Park spokeswoman.

While most people behave properly, the number engaging in illegal activity increased so much that the park this summer issued a plea for assistance in trying to educate visitors about park etiquette. The “Please Help Your Friends to Behave Better to Protect Rocky Mountain National Park” statement covered a variety of topics, including avoiding the park between 10 a.m. and 3 p.m. during the summer and fall, restrictions on campfires, keeping a distance from wildlife, not taking items from the wild, the prohibition on pets in most places, parking and, yes, bathroom habits.

“If your friend is a frequent pooper, suggest taking care of that before hiking. If nature calls, plan ahead — bring a waste bag, or research tips on how to poop in the woods,” it said. “Friends don’t let friends go to the bathroom near water sources. Just think, you might be drinking from that water source the next day!”