Feeding in Marine Mammals: An Integration of Evolution and Ecology through Time

Abstract

Marine mammals are a key component of aquatic ecosystems. Four major feeding strategies: suction, biting, filter feeding and grazing are identified in extant marine mammals (cetaceans, pinnipeds, sirenians, marine otters, and the polar bear) and associated with anatomical specializations of the head (e.g. rostrum, palate, temporomandibular joint, teeth/baleen, and mandible). Genetic and ontogenetic evidence of skull and tooth morphology provide the mechanisms that underlie patterns of feeding diversity. Based on a comprehensive diversity data set we provide an integrated analysis of the evolution of feeding, trophic structure and habitat (e.g. marine, riverine, estuarine) in fossil and extant marine mammals. We explore the origin and timing of particular feeding strategies over the last 50 million years. We find that the greatest diversity of pinnipedimorphs, cetaceans and extinct desmostylians occurred during the middle Miocene (11–15 million years ago, Ma). Sirenians reached their greatest diversity slightly earlier during the early Miocene (16–23 Ma). These historical data are used as a framework to inform the structure and trophic interactions of past, present and future marine ecosystems. We show that marine mammal generic diversity tracks diet with the greatest diversity of carnivores and herbivores in the middle Miocene. The drivers of diet and feeding patterns are both environmental (e.g. sea level fluctuations, climate change) and biotic (e.g. anatomical specializations, competition, predator‐prey) changes. The influence of these different processes on paleodiversity varies depending on taxonomic group, timing and geographic scale.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.