The elongated, spiraled tusk of male narwhals (Monodon monoceros) grows continuously throughout the life of the whale and is most likely a secondary sexual trait used in male–male hierarchical competition and possibly in female mate choice. Sex determination in narwhals is typically based on the presence (male) or absence (female) of an erupted tusk, but anomalies such as females with tusks, tuskless males or double-tusked whales occur, although infrequently. In this study, we collected reproductive data and recorded the presence or absence of a tusk in narwhals from the Inuit hunt in Greenland (1993 and 2010–19) with the purpose of estimating the frequency of tusk anomalies. We found that of the 173 whales, 2.9% displayed tusk anomalies. Tusked females constituted 1.5% of sampled females, tuskless males 2.8% of sampled males and double-tusked males 0.9% of sampled males. Biological information on a tusked female, a tuskless male and a double-tusked male was collected and is presented here. The tusked female was sexually mature, and 18 ovarian scars (indicating pregnancies) documented a long reproductive lifespan. The complete female tusk was estimated to be between 146 and 151 cm in length. The tuskless male was sexually maturing, as indicated by body dimensions, and the double-tusked male was sexually immature, with the two tusks measuring <90 cm in length. Although narwhals exhibit extremely low levels of genetic diversity, tusk anomalies persist in the populations, perhaps facilitated by the reproductive ability of whales with tusk anomalies.

雄性独角鲸（Monodon monoceros ）的细长、螺旋状的獠牙) 在鲸鱼的整个生命周期中不断生长，并且很可能是用于雄性与雄性等级竞争以及可能用于雌性配偶选择的第二性特征。独角鲸的性别决定通常基于长牙的存在（雄性）或不存在（雌性），但会发生异常，例如长牙的雌性、无牙的雄性或双牙鲸，尽管这种情况并不常见。在这项研究中，我们收集了生殖数据并记录了格陵兰岛因纽特人狩猎（1993 年和 2010-19 年）中独角鲸中是否存在长牙，目的是估计长牙异常的频率。我们发现，在 173 头鲸鱼中，有 2.9% 显示出长牙异常。有长牙的雌性占样本雌性的 1.5%，无长牙的雄性占样本雄性的 2.8%，双齿雄性占雄性样本的 0.9%。收集了长牙雌性、无长牙雄性和双长牙雄性的生物学信息，并在此处介绍。长着獠牙的雌性性成熟，18 处卵巢疤痕（表明怀孕）记录了较长的生殖寿命。据估计，完整的雌性象牙长度在 146 到 151 厘米之间。如身体尺寸所示，无牙雄性性成熟，双牙雄性性不成熟，两根獠牙长度小于 90 厘米。尽管独角鲸的遗传多样性水平极低，但象牙异常在种群中仍然存在，这可能是由于具有象牙异常的鲸鱼的繁殖能力所促进的。和 18 处卵巢疤痕（表明怀孕）记录了较长的生殖寿命。据估计，完整的雌性象牙长度在 146 到 151 厘米之间。如身体尺寸所示，无牙雄性性成熟，双牙雄性性不成熟，两根獠牙长度小于 90 厘米。尽管独角鲸的遗传多样性水平极低，但象牙异常在种群中仍然存在，这可能是由于具有象牙异常的鲸鱼的繁殖能力所促进的。和 18 处卵巢疤痕（表明怀孕）记录了较长的生殖寿命。据估计，完整的雌性象牙长度在 146 到 151 厘米之间。如身体尺寸所示，无牙雄性性成熟，双牙雄性性不成熟，两根獠牙长度小于 90 厘米。尽管独角鲸的遗传多样性水平极低，但象牙异常在种群中仍然存在，这可能是由于具有象牙异常的鲸鱼的繁殖能力所促进的。