Artistic Reconstruction of a Mother and Calf of Maiabalaena nesbittae (image) Smithsonian Share Print E-Mail Caption This is an artistic reconstruction of a mother and calf of Maiabalaena nesbittae nursing offshore of Oregon during the Oligocene, about 33 million years ago. While Maiabalaena would not have been able to chew or filter feed, muscle attachments on the bones of its throat indicate it likely had strong cheeks and a retractable tongue. These traits would have enabled it to suck water into its mouth, taking up fish and small squid in the process. The ability to suction feed would have rendered teeth, whose development requires a lot of energy to grow, unnecessary. The loss of teeth, then, appears to have set the evolutionary stage for the baleen, which the scientists estimate arose about 5 to 7 million years later. Credit Alex Boersma Usage Restrictions News-media use of these photos in relation to this study is permitted with attribution. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.