Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK.
Events Team, Blackpool Zoo, Blackpool, UK.
Anat Rec (Hoboken). 2022 Mar;305(3):556-567. doi: 10.1002/ar.24683. Epub 2021 Jun 2.
Pinniped vibrissae are well-adapted to sensing in an aquatic environment, by being morphologically diverse and more sensitive than those of terrestrial species. However, it is both challenging and time-consuming to measure vibrissal sensitivity in many species. In terrestrial species, the infraorbital foramen (IOF) area is associated with vibrissal sensitivity and increases with vibrissal number. While pinnipeds are thought to have large IOF areas, this has not yet been systematically measured before. We investigated vibrissal morphology, IOF area, and skull size in 16 species of pinniped and 12 terrestrial Carnivora species. Pinnipeds had significantly larger skulls and IOF areas, longer vibrissae, and fewer vibrissae than the other Carnivora species. IOF area and vibrissal number were correlated in Pinnipeds, just as they are in terrestrial mammals. However, despite pinnipeds having significantly fewer vibrissae than other Carnivora species, their IOF area was not smaller, which might be due to pinnipeds having vibrissae that are innervated more. We propose that investigating normalized IOF area per vibrissa will offer an alternative way to approximate gross individual vibrissal sensitivity in pinnipeds and other mammalian species. Our data show that many species of pinniped, and some species of felids, are likely to have strongly innervated individual vibrissae, since they have high values of normalized IOF area per vibrissa. We suggest that species that hunt moving prey items in the dark will have more sensitive and specialized vibrissae, especially as they have to integrate between individual vibrissal signals to calculate the direction of moving prey during hunting.
鳍足类动物的触须形态多样，比陆地物种的触须更敏感，非常适合在水生环境中感知，这使得它们适应了水生环境。然而，测量许多物种触须的敏感性既具有挑战性又耗时。在陆地物种中，眶下孔（IOF）区域与触须敏感性相关，并且随着触须数量的增加而增加。虽然人们认为鳍足类动物的 IOF 区域很大，但这尚未得到系统的测量。我们研究了 16 种鳍足类动物和 12 种陆地食肉动物的触须形态、IOF 区域和颅骨大小。鳍足类动物的颅骨和 IOF 区域明显更大，触须更长，触须数量更少。鳍足类动物的 IOF 区域和触须数量呈正相关，就像在陆地哺乳动物中一样。然而，尽管鳍足类动物的触须数量明显少于其他食肉动物，但它们的 IOF 区域并不小，这可能是因为鳍足类动物的触须有更多的神经支配。我们提出，研究每根触须的归一化 IOF 区域将提供一种替代方法来近似鳍足类动物和其他哺乳动物个体触须的总敏感性。我们的数据表明，许多鳍足类动物和一些猫科动物的每根触须的 IOF 区域都可能具有强烈的神经支配，因为它们的每根触须的归一化 IOF 区域具有很高的值。我们建议，在黑暗中捕猎移动猎物的物种将具有更敏感和专门化的触须，特别是因为它们必须整合个体触须信号来计算狩猎期间移动猎物的方向。
