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The Science, Ethics, and Philosophy of Tooth Extractions from Live-captured White-tailed Deer: a response to Festa-Bianchet et al. (2002)

Bite Size and Tooth Extraction

The basis of Festa-Bianchet et al.'s (2002) criticism of my conclusions begins with what is in their view the reasonable" assumption that the removal of the canine tooth reduces average bite size. From this, they conclude that food intake "could" be affected, hence reducing mass gain, reproduction, and "possibly" survival. Thus they deemed the procedure harmful.

Furthermore, they expressed dismay that I suggested a second canine could be extracted if the first one broke in a training session. Because Incisor 3 (I3) is essentially the same size, I further implied that it could be extracted in the rare event that two canines were broken during training. Recalling only one occasion when this had occurred, I re-examined the data for type of tooth aged. One I3 and possibly a second one had been extracted for aging. Including that I3 statement in my article (Nelson 2001) was more of a guide to where the limit should be in a failed training session. Once the procedure was learned, successful removal was the norm on the first attempt, and most breakage occurred in training sessions involving a few deer.

Perhaps some tooth measurements of the cutting edge of the incisor row will have some heuristic value here. I measured the incisor widths and lengths of the incisor row in a fresh 2-year-old road-killed female and in the dried collection jaws of three females 5, 8, and 15 years old killed by wolves (Canis lupus). The cutting edges of the canines ranged 1.0-1.7 mm and the incisor rows 21-32 mm. In these samples, removal of one canine would have represented a loss of 4-7% from the incisor row. The 15-year-old, which had extremely worn teeth, had the smallest incisor row and would have had the largest loss from the incisor row had the canine been removed.

As already indicated, bite size and foraging dynamics can be subject to conjecture. It is not my task here to present current knowledge about foraging ecology of deer. Perhaps the appropriate experts will want to weigh in on this topic someplace else. However, I will take the liberty to simply balance the assumption of lowered intake resulting from tooth removal, by adding two additional assumptions. Much, if not most, deer forage may have stem diameters well below the length of the incisor row, and annually, most forage is soft plant tissue, perhaps pulled from the ground as much as it is cut by the incisors. Northern forest deer restrict their winter feeding to <10-mm-diameter woody browse and simply break larger stems to reach smaller-diameter browse. Based on these facts and some added assumptions about forage characteristics, one might equally conclude that it is uncertain what losing a canine means to the biting dynamics of a deer.

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