The Heart of the Killer Whale: Description of a Plastinated Specimen and Review of the Available Literature

Abstract

The killer whale (Orcinus orca, Linnaeus, 1958) is the largest extant delphinid. Despite its worldwide distribution in the wild and in dolphinariums, its anatomy remains relatively poorly described. In the present study, we describe the detailed morphology of a plastinated killer whale heart. The gross description of the arteries and veins reaching the organ and its coronary vessels are reported. Additional endoscopy and CT (computed tomography) scanning were performed to provide extensive measurements of its parts. In many aspects, the killer whale heart conformed to other delphinid heart descriptions, including position, relative size and shape and specific features such as extensive papillary muscles, trabecular endocardium and trabecula septomarginalis. These characteristics are representative of the delphinid family, suggesting that its functions and capacities are similar to that of other, smaller, dolphins and help understand the conditions in which these predators exert their remarkable physical performance necessary for their survival.

Evolution of ion channels in cetaceans: A natural experiment in the Tree of life

“…Although the basic structure of the cetacean heart is similar to that of other mammals, based on our findings we hypothesized the importance of ion channels, among other proteins, in adapting to diving. Thus, besides the well-documented morphological changes in the cetacean heart (Tarpley et al 1997; Latorre et al 2022) mostly attributed to diving adaptations, our results show adaptive changes in genes encoding ion channels, which are fundamental for their physiological divergence.…”