Lacking the dietary minerals they’d find in their natural range, park officials say some of the goats (which were introduced to the area in the 1920s) have become “quite aggressive” when seeking human sources of salt. Namely, urine.

“They learn that salt comes from people and people pee on trails, so they follow you down the trail and wait until you pee,” said Dr. Patti Happe, the park’s wildlife branch chief. “People think that goats are chasing them when really they’re just following them, waiting for a handout.”

But mountain goats aren’t alone in their quest for liquid gold. A surprising number of creatures—from reindeer to locusts—have a known affinity for human urine. And for some species, this craving for our minerals has dramatically shaped their behavior.