Butti Camilla, Corain Livio, Cozzi Bruno, Podestà Michela, Pirone Andrea, Affronte Marco, Zotti Alessandro
Department of Experimental Veterinary Science, University of Padua, Italy.
J Anat. 2007 Nov;211(5):639-46. doi: 10.1111/j.1469-7580.2007.00805.x. Epub 2007 Sep 11.
The determination of age is an important step in defining the life history traits of individuals and populations. Age determination of odontocetes is mainly based on counting annual growth layer groups in the teeth. However, this useful method is always invasive, requiring the cutting of at least one tooth, and sometimes the results are difficult to interpret. Based on the concept that bone matrix is constantly deposited throughout life, we analysed the bone mineral density of the arm and forearm of a series of bottlenose dolphins (Tursiops truncatus, Montagu 1821) stranded along the Italian coast of the Adriatic Sea or maintained in confined waters. The bone mineral density values we obtained were evaluated as possible age predictors of the Mediterranean population of this species, considering age as determined by counting growth layer groups in sections of the teeth and the total body length of the animal as references. Comparisons between left and right flipper showed no difference. Our results show that bone mineral density values of the thoracic limb are indeed reliable age predictors in Tursiops truncatus. Further investigations in additional odontocete species are necessary to provide strong evidence of the reliability of bone mineral density as an indicator of growth and chronological wear and tear in toothed-whales.
确定年龄是界定个体和种群生活史特征的重要一步。齿鲸的年龄确定主要基于计算牙齿中的年度生长层组。然而，这种有用的方法总是具有侵入性，需要切割至少一颗牙齿，而且有时结果难以解释。基于骨基质在整个生命过程中持续沉积的概念，我们分析了一系列搁浅在亚得里亚海意大利海岸或饲养在封闭水域的宽吻海豚（Tursiops truncatus，蒙塔古，1821年）的臂骨和前臂骨的骨矿物质密度。我们将获得的骨矿物质密度值作为该物种地中海种群可能的年龄预测指标进行评估，将通过计算牙齿切片中的生长层组确定的年龄以及动物的全长作为参考。左右鳍状肢之间的比较没有差异。我们的结果表明，胸肢的骨矿物质密度值确实是宽吻海豚可靠的年龄预测指标。有必要对其他齿鲸物种进行进一步研究，以提供有力证据证明骨矿物质密度作为齿鲸生长和时间磨损指标的可靠性。
