剛好奇的去google出來這個：

https://www.crittercontrol.com/wildlife/porcupine/porcupines-in-the-winter

Porcupines are predominantly nocturnal, but during winter when food is more scarce, they will forage both day and night, insulated by their quills and dense guard hairs. During winter, its foraging territory changes, and porcupines stay much closer to their dens than in spring and summer when they can more easily travel for longer distances. Their foraging territory can shrink up to as much as 80-90 percent in winter as they need to save energy, so they retain stored fat through these leaner months. In winter when leaves are scarcer, porcupines will eat the bark of trees, waiting eagerly for spring when they can replenish their fat with new spring growth.

 

https://northernwoodlands.org/outside_story/article/porcupines-winter

Researchers in Quebec found that in years with deep snow, porcupine survival declined, primarily due to increases in predation and starvation, both of which resulted from the porcupine's inability to move around. Essentially, porcupines face a balancing act in which they must decide whether it is best to forage in a very small area, risking starvation due to limited food availability, or travel through the snow in order to gain access to additional food sources while risking predation.