Cetaceans face the challenge of maintaining equilibrium underwater and obtaining sensory input within a dense, low-visibility medium. The cetacean ear represents a key innovation that marked their evolution from terrestrial artiodactyls to among the most fully aquatic mammals in existence. Using micro-CT and histological data, we document shape and size changes in the cetacean inner ear during ontogeny, and demonstrate that, as a proportion of gestation time, the cetacean inner ear is precocial in its growth compared with that of suid artiodactyls. Cetacean inner ears begin ossifying and reach near-adult shape as early as at 32% of the gestation period, and near-adult dimensions as early as at 27% newborn total length. Our earliest embryos with measurable inner ears (13% newborn length) exhibit a flattened cochlea (i.e. smaller distance from cochlear apex to round window) compared with later and adult stages. Inner ears of Sus scrofa have neither begun ossifying nor reached near-adult dimensions at 55% of the gestation period, but have an adult-like ratio of cochlear diameters to each other, suggesting an adult-like shape. The precocial development of the cetacean inner ear complements previous work demonstrating precocial development of other cetacean anatomical features such as the locomotor muscles to facilitate swimming at the moment of birth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.