The Rubber Bandits of Mendenhall

Friday, December 1, 2017 6:00 PM by Laurie Craig, Forest Service, Retired

There was only light wind at the Mendenhall Glacier Visitor Center this summer, yet we would often come into work in the morning to find the entry doormats curled into a tube, as if a stiff breeze had rolled them up. But After a few days of puzzlement, and thanks to overnight technology and scientific research, the culprits were discovered.

Our investigation revealed the rug curlers were porcupines! These industrious creatures pulled and rolled the rug so they could gnaw the rubber backing. Little teeth marks were everywhere on the underside of the mats. They were nibbling the rubber for its salt content.

Porcupine Eating Rubber Mat

We are familiar with the salt needs of porcupines, especially in springtime when the rodents feast on fresh green leaves, mainly willows. The high levels of potassium-based salts in spring leaves demand more sodium-based salts to balance the animals’ intake and extract nutrients. Sometimes manmade sources of salt are easier to obtain than natural sources.

For years we have seen signs of porcupine-chewing on the wooden gates, benches, and the building siding. As respectful neighbors, we tried to discourage this behavior with bitter apple liquid and other natural deterrents. We even put out snack wood so the porcupines would eat tantalizing scraps of plywood instead of the equipment. Nothing seemed to work.

This summer, the visitor center porcupine population got more creative in their salt-seeking adventures. They started gnawing the rubber mats, rubber caution stanchions, and even licked the calcium seeping from the natural rocks and rock wall mortar. We’d step outside the staff door on a quiet evening and find a big porcupine standing on its rear legs licking the rock wall!

Porcupine Licking Salt

This summer, BBC and PBS created three, hour-long episodes of a special production called Wild Alaska Live using Mendenhall Glacier as their home base for June and July. Preparations included running a mile or more of electrical cable from their headquarters in the bus parking lot to several sites around the grounds. Porcupines chewed the rubber-covered cables and other equipment necessary for broadcasting, and that mischief earned them airtime! BBC produced a charming, 33-second porcupine problems trailer for the live series featuring porcupines and their impacts. You can watch it here You also can search online for Wild Alaska Live Porcupine Problems to view the short video.

For visitors, porcupines are a dependable wildlife viewing species. The rodents move slowly, have a natural defense system that creates caution in people, and tend to spend hours foraging on leaves within close proximity of visitors. Our guests’ most common comment is, “I didn’t know they could climb trees!” It is a terrific conversation starter for our interpreters to engage people in the life history of these amazing animals.

Porcupine Teeth

We revere these gentle beings that share our landscape. We protect them as well as we can so thousands of visitors from all over the world can watch a wild animal behave naturally in its surroundings. That is everything we, the Forest Service naturalists, want to give our guests.



Author: Laurie Craig, Forest Service, Retired

Laurie Craig was a naturalist and interpreter at the US Forest Service’s Mendenhall Glacier Visitor Center for more than 14 years. She organized and hosted the popular Fireside Lecture series each winter. She became well-known for her year-round newsletter messages and familiarity with the glacier’s bears. An artist by training, Laurie built essential connections between visitors, Juneau residents and wildlife with the goal of mutual respect and understanding. Laurie is enjoying retirement in Juneau and the return to her other profession as an artist.