Thursday, June 14, 2018

[Ecology • 2018] The Evolution of Foraging Capacity and Gigantism in Cetaceans


Different marine vertebrates exploiting a bait ball of forage fish.

in Goldbogen & Madsen, 2018.

ABSTRACT
The extant diversity and rich fossil record of cetaceans provides an extraordinary evolutionary context for investigating the relationship between form, function and ecology. The transition from terrestrial to marine ecosystems is associated with a complex suite of morphological and physiological adaptations that were required for a fully aquatic mammalian life history. Two specific functional innovations that characterize the two great clades of cetaceans, echolocation in toothed whales (Odontoceti) and filter feeding in baleen whales (Mysticeti), provide a powerful comparative framework for integrative studies. Both clades exhibit gigantism in multiple species, but we posit that large body size may have evolved for different reasons and in response to different ecosystem conditions. Although these foraging adaptations have been studied using a combination of experimental and tagging studies, the precise functional drivers and consequences of morphological change within and among these lineages remain less understood. Future studies that focus at the interface of physiology, ecology and paleontology will help elucidate how cetaceans became the largest predators in aquatic ecosystems worldwide.

Keywords: Scaling, Odontocetes, Mysticetes, Diving, Filter feeding, Echolocation


Fig. 1. Illustration of different marine vertebrates exploiting a bait ball of forage fish.
Among these species are many particulate feeders (e.g. cormorants, sea lions and dolphins), those that are largely limited to capturing one prey at a time. This contrasts with bulk filter feeding, characterized by the engulfment of large numbers of prey in a single mouthful, here represented by a humpback whale.
 Illustration by Alex Boersma.


J. A. Goldbogen and P. T. Madsen. 2018. The Evolution of Foraging Capacity and Gigantism in Cetaceans. Journal of Experimental Biology. 221: jeb166033. DOI: 10.1242/jeb.166033 


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