Interactions between asymmetric brow tines in caribou and reindeer antlers

• Published in: Canadian Journal of Zoology
• Main Author: Goss, Richard J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1990
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; caribou; Rangifer tarandus
• Online Access: http://dx.doi.org/10.1139/z90-165; http://www.nrcresearchpress.com/doi/pdf/10.1139/z90-165

The brow tines of caribou and reindeer (Rangifer tarandus) are typically asymmetric. One, usually the left, is branched or laterally compressed into a "shovel," the other remaining as an unbranched spike. Less commonly, both tines may be simple or both enlarged into the "double shovel" configuration. Analysis of 273 specimens confirmed the preponderance of left dominance in brow tines. Even when both are enlarged, the left one tends to be bigger. Bez tines arise more proximally on the antler when the brow tine is small or absent. Brow tines tend to converge medially. When one is larger than the other, the angle of growth with respect to the midline of the head averages 13.03° for the dominant tine and 6.22° for the smaller one. In double shovels, the brow tines are more parallel, averaging 7.31° from the midline. Sometimes the two tines grow above and below each other. These findings suggest that brow tines adapt their length and direction of elongation so as to avoid contact.