Cited by 181Evolution and Paleontology StudiesMarine animal studies overviewComparative Animal Anatomy Studies

Origin and evolution of large brains in toothed whales

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Marino, Lori, McShea, Daniel W., Uhen, Mark D.·2004·The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology

Abstract

Toothed whales (order Cetacea: suborder Odontoceti) are highly encephalized, possessing brains that are significantly larger than expected for their body sizes. In particular, the odontocete superfamily Delphinoidea (dolphins, porpoises, belugas, and narwhals) comprises numerous species with encephalization levels second only to modern humans and greater than all other mammals. Odontocetes have also demonstrated behavioral faculties previously only ascribed to humans and, to some extent, other great apes. How did the large brains of odontocetes evolve? To begin to investigate this question, we quantified and averaged estimates of brain and body size for 36 fossil cetacean species using computed tomography and analyzed these data along with those for modern odontocetes. We provide the first description and statistical tests of the pattern of change in brain size relative to body size in cetaceans over 47 million years. We show that brain size increased significantly in two critical phases in the evolution of odontocetes. The first increase occurred with the origin of odontocetes from the ancestral group Archaeoceti near the Eocene‐Oligocene boundary and was accompanied by a decrease in body size. The second occurred in the origin of Delphinoidea only by 15 million years ago. © 2004 Wiley‐Liss, Inc.

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Crossref · 10.1002/ar.a.20128

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  • The distribution of EQ values across cetaceans suggests that high levels of encephalization have evolved convergently multiple times.

    “The distribution of EQ values across cetaceans suggests that high levels of encephalization have evolved convergently multiple times (Marino 1998;Marino et al. 2004)”

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Authors
Marino, L., McShea, D. W., & Uhen, M. D.
Affiliations
  • Emory University (US)
  • Duke University (US)
  • Cranbrook Institute of Science (US)
Corresponding author
Marino, Lori
Venue
The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology
Publisher
Wiley
Published
2004-10-20
Volume
281A
Issue
2
Pages
1247-1255
ISSN
  • 1552-4884 (ISSN-L)
  • 1552-4892
OpenAlex
W2075414833
Cited by
181
References
32
Citations by year
2026: 2 · 2025: 10 · 2024: 6 · 2023: 12 · 2022: 5 · 2021: 12 · 2020: 6 · 2019: 8 · 2018: 5 · 2017: 7 · 2016: 8 · 2015: 4 · 2014: 10 · 2013: 10 · 2012: 7
FWCI
8.14
Type
journal article
Language
en
Open access
Locations
  • The Anatomical Record Part A Discoveries in Molecular Cellular and Evolutionary Biology (publishedVersion)
  • PubMed (publishedVersion)
  • WBI Studies Repository (submittedVersion)
Funders
National Science Foundation
Topics
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Evolution and Paleontology Studies
  • Physical Sciences › Environmental Science › Ecology › Marine animal studies overview
  • Health Sciences › Medicine › Urology › Comparative Animal Anatomy Studies
Keywords
brain size evolution, encephalization, odontocetes, Delphinoidea, fossil cetaceans, Archaeoceti, Eocene-Oligocene boundary, cetacean evolution
MeSH terms
Animals, Brain, Cetacea, Fossils, Tooth, Evolution, Molecular, Tomography, Spiral Computed, Body Size

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