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Encephalization quotients and life-history traits in the Sirenia

Journal of Mammalogy

By:
and
DOI:10.2307/1381792

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Abstract

Relative brain size in the Sirenia is unusually small. Encephalization quotients are 0.27 for Florida manatees (Trichechus manatus) and 0.38 for dugongs (Dugong dugon). Estimates for Steller's sea cow (Hydrodamalis gigas) range from 0.12 to 0.19. These values are among the lowest known for Recent mammals, and seemingly have changed little since the Eocene. A body plan specialized for the aquatic environment does not account for low encephalization quotients; values are substantially less than predicted based on cetacean or pinniped allometry. Life-history, ecological, and behavioral traits of the Sirenia are typical of relatively large-brained species. Low quality food and a low metabolic rate, however, are characteristic of the Sirenia and other small-brained mammals. Acting through prolonged postnatal growth, selection also likely favored large body size in the Sirenia without a correlated increase in brain size.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Encephalization quotients and life-history traits in the Sirenia
Series title:
Journal of Mammalogy
DOI:
10.2307/1381792
Volume:
71
Issue:
4
Year Published:
1990
Language:
English
Publisher:
Oxford University Press
Contributing office(s):
Florida Integrated Science Center
Description:
10 p.
First page:
534
Last page:
543
Online Only (Y/N):
N
Additional Online Files (Y/N):
N