The study, which will appear in the December issue of The Anatomical Record, was done by Emory psychologist Lori Marino, a faculty member in the university's Neuroscience and Behavioral Biology Program, and her colleagues Daniel McShea from Duke University and Mark Uhen from the Cranbrook Institute of Science. The paper is available online via Wiley InterScience at http://www.interscience.wiley.com/ar.
The study investigates the fossil record of the toothed whales (which includes dolphins, porpoises, belugas and narwhals) from the order Cetacea and suborder Odontoceti. Many modern toothed whale species (odontocetes) have extremely high encephalization levels possessing brains that are significantly larger than expected for their body sizes and second only to those of modern humans.
"A description of the pattern of encephalization in toothed whales has enormous potential to yield new insights into odontocete evolution, whether there are shared features with hominoid brain evolution, and more generally how large brains evolve," Marino says.
To investigate how the large brains of odontocetes changed over time, Marino and her colleagues quantified and averaged estimates of brain and body size for fossil cetacean species using computed tomography, and analyzed these data along with those for modern odontocetes.
The only data previously available were a small handful of fossils that provided a very li
Contact: Beverly Cox Clark
Emory University Health Sciences Center