Thirsty hikers have to wait. The elk are first in line.

The animals are helping themselves to water from bottle-filling stations set up around Grand Canyon National Park by lifting the spring-loaded levers with their noses and letting the water flow. It's not exactly the kind of use officials had in mind when they installed the stations and dropped the sale of disposable water bottles.

Now, they are elk-proofing the stations to outsmart the animals, conserve water and protect visitors from aggressive behavior.

About a dozen filling stations are set up throughout the park. The elk favor the one at popular South Kaibab Trail.

Chief resource manager Martha Hahn says caging in the water spout and changing up the way of turning on the water should keep the animals away.