Meeting Abstract
The narwhal tusk is undoubtedly one of the most charismatic structures in all of biology, protruding from the head of male narwhals and reaching lengths of up to 3-m. Recent evidence has arisen that proposes that narwhals may use their tusk to stun prey or sense changes in water quality. By contrast, because all males and only a small percentage of females develop a tusk; this suggests that the tusk may function as a weapon during male-male aggression or as a signal during female-mate choice. Hence, clear inconsistencies arise when attempting to distinguish between these functions. Because direct observations of narwhal behavior are nearly impossible, we studied morphological scaling and variation in adult narwhals. With our analyses, we demonstrate that the size of the narwhal tusk scales steeply with body size. Additionally, substantial variation in tusk size for a given body size supports the hypothesis that the tusk is sexually selected. Overall, we propose that the narwhal tusk is an exaggerated weapon used during male-male competition but may also serve additional functions.
