(also known as “picklepigs”) are vegetarians
that feed on the soft, inner bark of deciduous or
coniferous trees, and on buds, leaves and grasses.
Though their preference seems to be willows, cottonwoods
and aspen, they also feed on pinyons and orchard
trees. How much vegetation they consume in a day
is beyond me, but their conservative approach to
life must not require an excessive amount of fuel,
for they move at a glacier’s pace most of the
time. I have watched them scoot along canyon washes
or through open forests with surprising speed, but
that activity level is not the norm.
Porcupines, with their stout pairs of incisors, are
the largest members of the Rodent Family. Covered with
a formidable set of quills (somewhere around 30,000
per animal), a porcupine is not an easy target. Their
scientific name Eerethizon dorsatum is a combination
of Greek and Latin words that mean “irritates
with the back.” This reference is to the obvious
quills, which are really stiff and flexible modified
hairs. Each quill is armed at the tip with overlapping
barbs and these hairs easily break free from the skin
and embed themselves in the nosiest of noses.
A quill’s hollow tip swells and expands with
the attacker’s blood – a design feature
to make extraction more difficult. Of course, while
the animal is busy yelping in pain and trying to dislodge
the quills, the porcupine retreats to a safer location.
Most of my porcupine encounters involved searching
leafless trees in winter and keying in on the larger
masses in the crowns. Sometimes these blobs turned
out to be raptor nests or deadfall, but many times
they indicated a sleeping or feeding porcupine.
From these safe perches a porcupine can enjoy its winter
slumber while not worrying too much about predators
or pesky pets. Though their aerial chambers may lack
a variety of escape routes, their spiny pelts provide
them ample protection from most predators. Cougars,
bobcats, coyotes, martins, fishers, great horned owls,
and bald eagles have been known to take porcupines
Though predators often get a mouth or nosefull of quills,
porcupines are not immune to predation. Cougars and
coyotes know that quill-throwing porcupines are a thing
of legends, and that either the soft underbelly of
a porcupine or its quillless face are little match
for razor-sharp claws. When confronted, a porcupine
will turn about, look over its shoulder and use its
tail to swipe at a predator. Also, a porcupine will
stamp its feet and arch its back as defensive signals – just
like a skunk. Maybe that is why cougars prefer to run
down a mule deer than to tangle with a porcupine.
The common name porcupine is derived from the Latin
porcospinus and this translates into “quilled
pig.” Though named for its hairs, the porcupine
also has long, sharp claws and rough foot soles that
provide a good grip while climbing. The texture of
these pads is evident when observing the porcupine’s
tracks, especially in sandy conditions.
But these dimpled soles are not the only clue that
betrays a porcupine’s passage down a canyon wash.
The porcupine’s bow-legged gait is another helpful
clue in track identification. Of course, dragging behind
the tracks is the “spiny” tail, which leaves
an impression of a broom being used to sweep up behind
Active throughout the year, porcupines don’t
hibernate in winter. They will sleep for several days
if the weather is very cold and may “den up” in
a cave, tree hollow or stump with other porcupines.
When several porcupines occupy the same winter den
they are referred to as a “pickle of porcupines.” Seriously.
Porcupines rely on their weight gained during the spring
and summer to carry them through winter. Sometimes
people observe porcupines chewing on an old boot, wooden
handle or saddle, but this is not a starvation survival
technique. Rather, this rodent is obtaining salt residue
left on from sweat or urine. Porcupines may chew on
these and other calcium-rich objects like antlers,
bones or bleaching skulls any time of the year.
For a female porcupine, winter is not just a season
for one. Adult females are partway through their 6 ½ to
7 month gestation period, having bred sometime in November
or December. This is a long gestation period for a
rodent, and unlike mice or rabbits, porcupines generally
give birth to one young (called a porcupette - seriously)
in late spring or early summer.
What seems like an extremely painful birthing process
is somewhat relieved by the young being born headfirst
in a placental sac. The soft quills are appressed to
the body and will not harden until about an hour after
birth. The young are mobile shortly after birth and
are good climbers like the adults.
For a wild adult porcupine, old age is around 5-7 years
old. Though they occupy a place in the web of nature,
porcupines have been given a bad rap because of their
tree-girdling tendencies. Years ago in Central Oregon,
there were highway signs that stated “Please
kill all porcupines” to motorists. Crossing the
roadway to get to the proverbial other side was a danger
greater than predators.
So if you encounter a winter picklepig, take a moment
to observe its activity. Don’t regard it is a “killer
of trees” but as a unique creature of the canyons,
quills and all.