Mécanismes Adaptatifs et Evolution (MECADEV), Muséum National d'Histoire Naturelle, CNRS, 55 rue Buffon, 75005 Paris, France
Archéozoologie, Archéobotanique: Sociétés, Pratiques et Environnements (AASPE), Muséum National d'Histoire Naturelle, CNRS, CP55, 57 rue Cuvier, 75005 Paris, France.
J Exp Biol. 2020 Aug 17;223(Pt 16):jeb224352. doi: 10.1242/jeb.224352.
Previous studies based on two-dimensional methods have suggested that the great morphological variability of cranial shape in domestic dogs has impacted bite performance. Here, we used a three-dimensional biomechanical model based on dissection data to estimate the bite force of 47 dogs of various breeds at several bite points and gape angles. bite force for three Belgian shepherd dogs was used to validate our model. We then used three-dimensional geometric morphometrics to investigate the drivers of bite force variation and to describe the relationships between the overall shape of the jaws and bite force. The model output shows that bite force is rather variable in dogs and that dogs bite harder on the molar teeth and at lower gape angles. Half of the bite force is determined by the temporal muscle. Bite force also increased with size, and brachycephalic dogs showed higher bite forces for their size than mesocephalic dogs. We obtained significant covariation between the shape of the upper or lower jaw and absolute or residual bite force. Our results demonstrate that domestication has not resulted in a disruption of the functional links in the jaw system in dogs and that mandible shape is a good predictor of bite force.
先前基于二维方法的研究表明，家犬颅骨形态的巨大形态变异性影响了其咬合力。在这里，我们使用了基于解剖数据的三维生物力学模型来估计 47 只不同品种犬在几个咬合点和张口角度的咬合力。我们使用三只比利时牧羊犬的咬合力来验证我们的模型。然后，我们使用三维几何形态测量学来研究咬合力变化的驱动因素，并描述颌骨整体形状与咬合力之间的关系。模型输出表明，犬类的咬合力差异较大，且犬类在磨牙上咬得更用力，张口角度也更小。咬合力的一半取决于颞肌。咬合力也随体型增大而增大，短头犬比中头犬的相对咬合力更大。我们发现上颌或下颌的形状与绝对咬合力或残差咬合力之间存在显著的协变关系。我们的研究结果表明，犬类的驯化并没有破坏颌骨系统中的功能联系，而且下颌骨的形状是咬合力的一个很好的预测指标。
