The patterns that a porcupine’s incisors leave when a porcupine has been removing bark down to the cambium can be a work of art. The way in which a porcupine makes these patterns is as intriguing as the patterns themselves. “The porcupine removes the bark in small triangular patches, each patch composed of five or six scrapes converging on an apex, like sticks in a teepee. The apex represents the position of the upper incisors, held fixed against the bark. The lower incisors scrape, moving over a fresh path as the lower jaw swivels in a narrow arc.” (Uldus Rose, The North American Porcupine) Fortunately, porcupine incisors, like those of all rodents, grow continually. Even though each incisor loses 100% of its length to wear in a year’s chewing, its length always remains the same. Juvenile porcupines leave a much less “organized” set of incisor marks (overlapping, randomly placed) than adults.
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