The Porcupine Surviving With A Good Defense
Fall 2015
By Bill Taylor, Chairman of the Board
The porcupine is so well-known that it does not require much description here. It is Michigan's second largest rodent (behind the beaver), and typically reaches 30 to 36 inches in length and 15 to 25 pounds in weight. These figures include a small head, a chunky body, and a short, thick tail. The upper body is covered with thick black fur and white-tipped guard hairs that conceal several thousand sharp quills. The quills are also black and white, and rise up through the fur when the porcupine becomes alarmed. Porcupines currently inhabit Michigan's Upper Peninsula and the northern part of our Lower Peninsula. They also range northward to Labrador in the east
and Northern Alaska in the west. As a result, the North American porcupine is commonly thought of as a North Woods animal.
However, the species can survive further south than its present range, and occupied nearly all of Michigan in early settlement times. It also inhabited several southeastern states, and still inhabits mountainous areas as far south as New Mexico in the West. In other words, it is not an inherently far northern species.
The popular image of a porcupine sitting in a tree eating bark also greatly oversimplifies its diet. North American porcupines do feed heavily on the inner in the warm months. They also have a craving for salt, and are notorious for chewing wooden objects like axe handles that contain salt from sweaty human hands.
Some friends and I saw how versatile porcupine diets can be when we hiked into the Montana badlands area known as the Missouri Breaks to see an old Indian site several years ago. The site was located in a natural chamber in a large sandstone formation, and there was virtually no vegetation in the area except grass and occasional low shrubs and prickly pear cactuses. As a result, we were extremely surprised to find a porcupine concealed in a rock crevice just below the site. Then we found a sizable collection of prickly pear cactus segments stashed in a separate crevice.
I have never read anything about porcupines storing food or eating prickly pear cactuses, and cannot be certain that this one created the cache. However, we did not see any evidence of known hoarders like wood rats, and the cache was located within a few feet of a healthy porcupine. While the prickly pear connection is speculative, we definitely found a healthy porcupine living in an area with very little traditional porcupine food.
Strangely, most of my other unusual porcupine encounters also occurred in Montana. One of these dates back several decades to the time when one of my Flathead Forest co-workers shot a porcupine that was girdling a nice stand of trees. However, he failed to kill it, and two of us ran alongside the mortally wounded animal and dispatched it with clubs. I was extremely careful to stay out of the porcupine's reach, but still found several four inch quills sticking through the folds in my jeans. This episode taught me a valuable lesson on how these clumsy-looking animals can flick their tails against an attacker faster than the eye and brain can register it.
Many years later some friends and I watched a coyote test a porcupine's defenses in Montana
cattle country. The coyote kept circling the porcupine, and the porcupine kept turning with it to keep the long quills on its tail and backside in the coyote's face. The coyote loped away when we moved closer, but I had the impression that it would never have seriously attacked this vigilant porcupine.
Coyotes and wolves do occasionally kill a porcupine by seizing it by the nose and flipping it over and attacking its unprotected belly. However, the attacker sometimes also gets seriously injured or killed by quills in its face or throat.
Cougars attack porcupines in the same way, and are more adept at killing them and extracting any
quills that they pick up in the process than these canine predators. However, the large members of the weasel family known as fishers are the most effective porcupine predators of all. Fishers are extremely quick, and have been observed killing porcupines by either flipping them over on their backs or repeatedly biting their faces.
The Upper Peninsula's porcupine population has declined significantly in recent decades, and fishers seem to be a major factor. Porcupines were abundant and fishers were practically extinct in Michigan when the DNR began releasing Minnesota fishers in the Western Upper Peninsula in the early 1960s. Porcupine numbers decreased markedly as the fishers established themselves, and studies suggested a cause and effect relationship. Then the DNR relocated fishers to the Eastern Upper Peninsula in the late 1980s and early 1990s, and porcupines declined there in the same way.
On the other hand, porcupines have also declined in several western states and Canadian provinces without major changes in fisher numbers. This situation is particularly puzzling in Montana, where the largest porcupine decreases have occurred in the State's most suitable high elevation forests. One Montana wildlife official has cautioned that something as mundane and hard-to-detect as a new rodent disease may be contributing to the species' difficulties.
Whatever the cause of their decline, the Upper Peninsula and Northern Lower Peninsula still have enough porcupines to fascinate youngsters and teach dogs painful lessons about bothering them. In fact, porcupines seem to be re-colonizing some near-North localities like Saginaw and Montcalm Counties as their forest lands increase. More surprising, a few dead porcupines have also turned up along roads as far south as Berrien, Clinton, and Eaton Counties. These finds have generated a variety of speculation, and the MWC would appreciate hearing from readers who observe porcupines in Southern Michigan.
By Bill Taylor, Chairman of the Board
The porcupine is so well-known that it does not require much description here. It is Michigan's second largest rodent (behind the beaver), and typically reaches 30 to 36 inches in length and 15 to 25 pounds in weight. These figures include a small head, a chunky body, and a short, thick tail. The upper body is covered with thick black fur and white-tipped guard hairs that conceal several thousand sharp quills. The quills are also black and white, and rise up through the fur when the porcupine becomes alarmed. Porcupines currently inhabit Michigan's Upper Peninsula and the northern part of our Lower Peninsula. They also range northward to Labrador in the east
and Northern Alaska in the west. As a result, the North American porcupine is commonly thought of as a North Woods animal.
However, the species can survive further south than its present range, and occupied nearly all of Michigan in early settlement times. It also inhabited several southeastern states, and still inhabits mountainous areas as far south as New Mexico in the West. In other words, it is not an inherently far northern species.
The popular image of a porcupine sitting in a tree eating bark also greatly oversimplifies its diet. North American porcupines do feed heavily on the inner in the warm months. They also have a craving for salt, and are notorious for chewing wooden objects like axe handles that contain salt from sweaty human hands.
Some friends and I saw how versatile porcupine diets can be when we hiked into the Montana badlands area known as the Missouri Breaks to see an old Indian site several years ago. The site was located in a natural chamber in a large sandstone formation, and there was virtually no vegetation in the area except grass and occasional low shrubs and prickly pear cactuses. As a result, we were extremely surprised to find a porcupine concealed in a rock crevice just below the site. Then we found a sizable collection of prickly pear cactus segments stashed in a separate crevice.
I have never read anything about porcupines storing food or eating prickly pear cactuses, and cannot be certain that this one created the cache. However, we did not see any evidence of known hoarders like wood rats, and the cache was located within a few feet of a healthy porcupine. While the prickly pear connection is speculative, we definitely found a healthy porcupine living in an area with very little traditional porcupine food.
Strangely, most of my other unusual porcupine encounters also occurred in Montana. One of these dates back several decades to the time when one of my Flathead Forest co-workers shot a porcupine that was girdling a nice stand of trees. However, he failed to kill it, and two of us ran alongside the mortally wounded animal and dispatched it with clubs. I was extremely careful to stay out of the porcupine's reach, but still found several four inch quills sticking through the folds in my jeans. This episode taught me a valuable lesson on how these clumsy-looking animals can flick their tails against an attacker faster than the eye and brain can register it.
Many years later some friends and I watched a coyote test a porcupine's defenses in Montana
cattle country. The coyote kept circling the porcupine, and the porcupine kept turning with it to keep the long quills on its tail and backside in the coyote's face. The coyote loped away when we moved closer, but I had the impression that it would never have seriously attacked this vigilant porcupine.
Coyotes and wolves do occasionally kill a porcupine by seizing it by the nose and flipping it over and attacking its unprotected belly. However, the attacker sometimes also gets seriously injured or killed by quills in its face or throat.
Cougars attack porcupines in the same way, and are more adept at killing them and extracting any
quills that they pick up in the process than these canine predators. However, the large members of the weasel family known as fishers are the most effective porcupine predators of all. Fishers are extremely quick, and have been observed killing porcupines by either flipping them over on their backs or repeatedly biting their faces.
The Upper Peninsula's porcupine population has declined significantly in recent decades, and fishers seem to be a major factor. Porcupines were abundant and fishers were practically extinct in Michigan when the DNR began releasing Minnesota fishers in the Western Upper Peninsula in the early 1960s. Porcupine numbers decreased markedly as the fishers established themselves, and studies suggested a cause and effect relationship. Then the DNR relocated fishers to the Eastern Upper Peninsula in the late 1980s and early 1990s, and porcupines declined there in the same way.
On the other hand, porcupines have also declined in several western states and Canadian provinces without major changes in fisher numbers. This situation is particularly puzzling in Montana, where the largest porcupine decreases have occurred in the State's most suitable high elevation forests. One Montana wildlife official has cautioned that something as mundane and hard-to-detect as a new rodent disease may be contributing to the species' difficulties.
Whatever the cause of their decline, the Upper Peninsula and Northern Lower Peninsula still have enough porcupines to fascinate youngsters and teach dogs painful lessons about bothering them. In fact, porcupines seem to be re-colonizing some near-North localities like Saginaw and Montcalm Counties as their forest lands increase. More surprising, a few dead porcupines have also turned up along roads as far south as Berrien, Clinton, and Eaton Counties. These finds have generated a variety of speculation, and the MWC would appreciate hearing from readers who observe porcupines in Southern Michigan.