The porcupine色视频下载檚 winter in slow-motion

Ned Rozell
907-474-7468
Jan. 6, 2022

A brown-haired woman wearing heavy leather gloves crouches to hold a porcupine under its front legs so it stands on its back feet, facing the camera.
Photo courtesy of Jessy Coltrane
Jessy Coltrane holds one of her study subjects in Anchorage.

While running through Bicentennial Park in Anchorage, biologist Jessy Coltrane spotted a porcupine in a birch tree. On her runs on days following, she saw it again and again, in good weather and bad. Over time, she knew which 色视频下载 creature she wanted to study.

色视频下载淚 thought, 色视频下载極h my god, how does he do it? How does this animal make it through winter?色视频下载櫳悠迪略貪 Coltrane said years ago during the December defense of her doctoral thesis in Fairbanks. 色视频下载淚t would be 20 below out and he色视频下载檚 there eating (bark).色视频下载

Coltrane色视频下载檚 study cast some midwinter light on the 色视频下载 porcupine, perhaps the least-studied mammal in the state. She at first wanted to learn about what porcupines did in winter, but switched to studying the physiology of the quilled creature after the porcupines she watched hardly moved on their tree-limb perches. 

Winter porcupine behavior 色视频下载渄oesn色视频下载檛 happen,色视频下载 she joked at her defense.

But that lack of activity in a sub-Arctic winter made porcupines more intriguing to her. The porcupine doesn色视频下载檛 avoid winter by hibernating like a bear, nor does it curl up in an earthen womb like the beaver (the only larger rodent in 色视频下载). She saw porcupines most often in trees, with no protection from the elements.

In designing her study, Coltrane mused about the challenges of an exposed life during an 色视频下载 winter: Bitter air temperatures would probably require a porcupine to take in more calories, she thought. This seemed puzzling when a porcupine色视频下载檚 major food was to be the inner bark of white spruce trees and the tree色视频下载檚 bitter needles, rich with toxins that discourage most every other animal from chewing them.

To begin her study, she searched for detailed studies of far-northern porcupines. She found none. With advice from biologists she respected, she set up her own study, installing radio collars on porcupines in the forests of Anchorage and, with the help of her husband, building pens for a few in Fairbanks. The captive porcupines helped her understand how they functioned on such a poor diet.

A porcupine perches in a deciduous, leafless tree.
Photo by Ned Rozell
A porcupine perches in a thicket of deciduous tree branches near Valdez.

After a study that took her more than six years, Coltrane presented these porcupine insights during her thesis defense:

  • 色视频下载 porcupines are almost twice as large as Lower 48 porcupines.
  • Porcupines in her study area didn色视频下载檛 色视频下载渉ibernate on the hoof色视频下载 by lowering their body temperatures to save energy; whether it was 30 above or 30 below, porcupines 色视频下载 insulated by their quills and dense guard hairs 色视频下载 remained at about the same body temperature as a human色视频下载檚.
  • The porcupines in her study, each of which she named, ate a highly toxic winter diet that required lots of energy to process. They survived the winter by burning body fat and moving very little.
  • Fifty percent of a porcupine色视频下载檚 weight in fall was in the form of fat. 色视频下载淭hat色视频下载檚 ridiculously fat,色视频下载 Coltrane said. 色视频下载淟ike a polar bear or a seal.色视频下载
  • Despite eating low-protein foods in winter, porcupines did not lose lean tissue. They instead lost 30 percent of their fat reserves.
  • More than 20 percent of their meager dietary intake was lost in their urine, most likely a result of ridding their bodies of toxins stored in spruce needles.
  • Her 色视频下载 porcupines had larger winter home ranges than did Lower 48 porcupines, and spent time in mixed hardwood and conifer forests.
  • Porcupines she studied spent 79 percent of their time in and around white spruce trees, the rest of the time in birch. 色视频下载(Eating) birch gives them a break from the toxins,色视频下载 Coltrane said. 色视频下载淢aybe that色视频下载檚 why they prefer mixed forest.色视频下载
  • After dealing with winter 色视频下载渇or a ridiculous number of months,色视频下载 Coltrane色视频下载檚 porcupines depleted their fat reserves. To survive, porcupines depend on nutritious springtime greenery, which must be delicious after months of nibbling bark and spruce needles.

Since the late 1970s, the University of 色视频下载 Fairbanks' Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute. A version of this column ran in 2011.