March 21, 2019 at 6:46 pm
By Regional Widlife Biologist Scott McLellan
Obviously, a porcupine has few predators because of how well-armed with quills it is (approximately 30,000), but one of the more fascinating prey/predator interactions exists between the porcupine and fisher. The fisher, which is a member of the weasel family, has carved out a hunting strategy that enables it to seek out and successfully kill porcupines. Known for being a very aggressive and opportunistic predator, the fisher has figured out how to repeatedly attack the only exposed part of the porcupine’s body (the face) that does not have any quills. The porcupine’s main method of defense, when possible, is to keep its face toward the trunk of a tree and charge backwards with a flailing tail.
The precision of the fishers’ attacks is not perfect, as they often become embedded with quills as a result. A significant amount of research has been done to understand this phenomenon, and as many as 2/3 of male fisher have carried quills in some studies. In each study, a much smaller percent of female fisher showed signs of having attacked a porcupine. As painful as it may seem (some fisher had over 100 quills), the quills do not seem to have any apparent effects on their health (no signs of inflammation or harmful effects). Many quills have been found embedded deep within muscle tissue and against bone, while many others lie between the skin and muscle matter. A study conducted by the University of Maine at Orono during the 1980’s revealed that snowshoe hare and porcupines were the most common mammal species found within a large sample of scats, suggesting that porcupines are an important food source for fisher in some areas of Maine.
[caption id="attachment_3414" align="aligncenter" width="500"]
Porcupine and fisher at different time intervals during winter of 2019 in the Moosehead Lake region. [/caption]
While conducting other work this winter, I located a heavily-used porcupine trail, followed it to a den, and placed a game camera on a tree facing toward the den. Not having any expectations, I left the camera in place for about 6 weeks during the early part of 2019. I collected over 550 photos of 2 different porcupines (all but 4 of the photos were during the night), 2 photos of snowshoe hare, 1 photo of a weasel, and 5 photos of a fisher. There was no attempt to enter the den by the fisher, but instead, it appeared to be passing through while conveniently travelling the beat-down trail, possibly hoping to encounter a porcupine out of its den. There were no photos of red fox, coyote, lynx or bobcat, and it has been hypothesized that the taller height of these predators puts them at a disadvantage against an attack of the porcupine’s face. I suspect that the other predators do not mind letting the fisher have that meal all to itself!
Obviously, a porcupine has few predators because of how well-armed with quills it is (approximately 30,000), but one of the more fascinating prey/predator interactions exists between the porcupine and fisher. The fisher, which is a member of the weasel family, has carved out a hunting strategy that enables it to seek out and successfully kill porcupines. Known for being a very aggressive and opportunistic predator, the fisher has figured out how to repeatedly attack the only exposed part of the porcupine’s body (the face) that does not have any quills. The porcupine’s main method of defense, when possible, is to keep its face toward the trunk of a tree and charge backwards with a flailing tail.
The precision of the fishers’ attacks is not perfect, as they often become embedded with quills as a result. A significant amount of research has been done to understand this phenomenon, and as many as 2/3 of male fisher have carried quills in some studies. In each study, a much smaller percent of female fisher showed signs of having attacked a porcupine. As painful as it may seem (some fisher had over 100 quills), the quills do not seem to have any apparent effects on their health (no signs of inflammation or harmful effects). Many quills have been found embedded deep within muscle tissue and against bone, while many others lie between the skin and muscle matter. A study conducted by the University of Maine at Orono during the 1980’s revealed that snowshoe hare and porcupines were the most common mammal species found within a large sample of scats, suggesting that porcupines are an important food source for fisher in some areas of Maine.
[caption id="attachment_3414" align="aligncenter" width="500"] Porcupine and fisher at different time intervals during winter of 2019 in the Moosehead Lake region. [/caption]
While conducting other work this winter, I located a heavily-used porcupine trail, followed it to a den, and placed a game camera on a tree facing toward the den. Not having any expectations, I left the camera in place for about 6 weeks during the early part of 2019. I collected over 550 photos of 2 different porcupines (all but 4 of the photos were during the night), 2 photos of snowshoe hare, 1 photo of a weasel, and 5 photos of a fisher. There was no attempt to enter the den by the fisher, but instead, it appeared to be passing through while conveniently travelling the beat-down trail, possibly hoping to encounter a porcupine out of its den. There were no photos of red fox, coyote, lynx or bobcat, and it has been hypothesized that the taller height of these predators puts them at a disadvantage against an attack of the porcupine’s face. I suspect that the other predators do not mind letting the fisher have that meal all to itself!Categories