Zoo keepers thought Shooter, a 4-year-old elk, was trying to climb in a tank because he was sniffing and pawing at it.
But after he was able to position his antlers, they watched him reach into the water and grab a marmot out.
The elk then set him on the ground and began nudging him with his hoof.
"We're not sure if he just sensed that this marmot was in distress or whether he didn't like it in his way. He spent quite a bit of time like planning how to grab it," said Dr. Joy Fox of the Pocatello Zoo.
After a little time catching his breath, the rescued marmot scampered home, much to the delight of zoo keepers.