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Zion's Misunderstood Rodents

Zion National Park

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Zion’s Misunderstood Rodents

The visitor pointed to my photograph of the hand with the nasty bite and stitches. “What did that?” he asked. “A rock squirrel,” I replied, pointing to a photograph of a chubby-looking rodent with bright brown eyes. “I’ve seen a lot of them on this trail,” the visitor continued. “That’s why we show these photos as part of the River Rendezvous program,” I explained. “Some people feed and even try to pet the rock squirrels here, and we want them to know that’s dangerous. It’s not good for the rock squirrels, either.”

I had set up my photographs on a bench about three-quarters of the way up the one- mile Riverside Walk. It faced a sandy alcove tucked back against towering cliffs of Navajo Sandstone. Behind the bench, the Virgin River tumbled, sounding unusually loud as it echoed between narrowing canyon walls. For the next hour and a half, I would be answering visitor questions and talking about the plants and wildlife they might encounter. One of the most commonly observed animals along the trail is the rock squirrel (Spermophilus variegatus).

The Riverside Walk offers ideal rock squirrel habitat. They prefer rocky locations including cliffs, canyon walls, and boulder piles. They dig burrows and raise their babies under large rocks, and they use rocks as lookout points. Classified as ground squirrels, they can climb trees almost as well as tree squirrels, and will forage and seek shelter high on limbs and branches as well as on the ground.

Less than fifteen minutes into my program, I noticed a rock squirrel digging in the sand next to my bench. With its sharp front claws it unearthed a round, dark object, then suddenly leaped to one edge of the bench. There it sat, rapidly twirling the object in its paws while gnawing.

Visitors were now gathering to watch and photograph the squirrel. Apparently quite unalarmed by the attention it was getting as it ate, it seemed to exemplify the words visitors frequently use to describe it: “Cute. Tame. Friendly.”

Although rock squirrels may be cute, they are anything but tame and friendly. Their apparent friendliness is actually a lack of fear of humans and a desire to secure food. Their sharp, chisel-like incisors are capable of slicing through barriers—including human skin—in a matter of seconds and are well-adapted for their incredibly varied natural diet: vegetation, flowers, acorns, pinyon pine nuts, cactus and cactus fruit, berries, and roots and tubers. They also eat invertebrates, such as beetles and grasshoppers. They will hunt and kill small rodents and birds, even young wild turkeys, and eat carrion.

Against one predator, the western diamondback rattlesnake, rock squirrels have developed a formidable defense. In a behavior that is called “mobbing,” the squirrel will lunge forward repeatedly and wave its tail from side to side, kicking sand and rocks at the snake’s head. It will even bite the snake if it gets the opportunity. If a squirrel gets bitten, it may not be affected. Adult rock squirrels have evolved the capacity to at least partially neutralize the venom. Even more remarkably, recent research indicates that rock squirrels may apply snake scent to their bodies to camouflage their own scent. This may be especially important in the young, who have not yet developed resistance to the snake’s deadly bite.

It is easy for us to misunderstand the rock squirrel as we stroll along the Riverside Walk, glimpsing only a brief moment in its daily drama of survival. The often harsh realities of life in Zion forces it to forage, hunt, raise babies, and defend itself and them from enemies—in a struggle often far removed from human view. We can help by respecting—and not interfering—with its skills and status as a wild creature.

Amy Gaienne

Description

Learn about the misunderstood rock squirrel with Park Ranger Robin Hampton in her reading of an article written for the park's Nature Notes by Park Ranger Amy Gaiennie.