Porcupines

How familiar are you with porcupines? I suspect most people associate porcupines with forest, but if you are familiar with this prickly mammal you may know that they can be found over much of the state, and that includes the western portions. I was reminded of that recently when I was out in the badlands and, as occasionally happens, ran across a porcupine out in the middle of nowhere in a buckbrush patch.

Out of curiosity I checked the Biological Survey of North Dakota by Vernon Bailey, from 1926. He considered porcupines to be quite scattered and rare east of the Missouri River at that time, but fairly common along the Missouri River and westward. He reported that they were often observed in the badlands in such places as brushy stream bottoms and buffaloberry thickets.

Bailey also noted that a good portion of the ponderosa pines near Marmarth showed porcupine damage and referenced the bushy tops and gnarled forms. He even went so far as to blame porcupines for the scarcity of trees in the area.

I quote:

“It is not improbable that they are largely responsible for the scarcity
of timber in the Badlands region; were it not for them a fair stand of
pines might have spread over this rough country. If reforestation of these
areas is attempted, it will be necessary to first eliminate the porcupines,
as where they are common no young trees can reach a well-deserved maturity.”

Barkless branches near the tops of some trees in a sure sign of porcupine damage. What might be more widely observable but less noticed, are the long term affects of porcupines feeding on these treetops.

Porcupines generally feed on the leaves of trees by gnawing off young twigs containing some leaves and buds. With the terminal bud removed, that particular twig is done growing, but it does stimulate adjacent lateral buds to grow. Before long, the old stub may have some short twigs growing out from it.

If the porcupine then browses the regrowth, the whole process is repeated. Over a few years a congested cluster of short twigs will have grown at the top of the tree. It’s really quite obvious once you’ve noticed it. The treetop looks heavily pruned with the ends of the remaining branches supporting a cluster of short twigs. Once you’ve seen one of these trees, you’ll easily identify others. As you travel around, take note of the treetops. There may be more porcupines in your area than you thought.

Chuck Lura

Natural North Dakota is supported by NDSU Central Grasslands Research Extension Center and Dakota College at Bottineau, and by the members of Prairie Public. Thanks to Sunny 101.9 in Bottineau for their recording services.