Severe Bone Loss as Part of the Life History Strategy of Bowhead Whales.

The evolution of baleen constituted a major evolutionary change that made it possible for baleen whales to reach enormous body sizes while filter feeding on tiny organisms and migrating over tremendous distances. Bowhead whales (Balaena mysticetus) live in the Arctic where the annual cycle of increa...

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Bibliographic Details
Published in:PLOS ONE
Main Authors: John C George, Raphaela Stimmelmayr, Robert Suydam, Sharon Usip, Geof Givens, Todd Sformo, J G M Thewissen
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2016
Subjects:
Medicine
R
Science
Q
Arctic
The Ribs
Balaena mysticetus
baleen whales
Online Access:https://doi.org/10.1371/journal.pone.0156753
https://doaj.org/article/76e0426367f24a03b76ab952d9f6f601
Description
Summary:The evolution of baleen constituted a major evolutionary change that made it possible for baleen whales to reach enormous body sizes while filter feeding on tiny organisms and migrating over tremendous distances. Bowhead whales (Balaena mysticetus) live in the Arctic where the annual cycle of increasing and decreasing ice cover affects their habitat, prey, and migration. During the nursing period, bowheads grow rapidly; but between weaning and approximately year 5, bowhead whales display sustained baleen and head growth while limiting growth in the rest of their bodies. During this period, they withdraw resources from the skeleton, in particular the ribs, which may lose 40% of bone mass. Such dramatic changes in bones of immature mammals are rare, although fossil cetaceans between 40 and 50 million years ago show an array of rib specializations that include bone loss and are usually interpreted as related to buoyancy control.

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