The New York Times Interviews Whale Evolution Expert

The New York Times interviewed Jonathan Geisler, Ph.D., chair of the department of anatomy, regarding the discovery of a miniature whale dubbed, Tutcetus rayanensis, which lived approximately 40 million years ago. Geisler, who was not involved in the study but is an expert on the evolutionary history of Cetacea (whales, dolphins, and porpoises) discussed the evolution of body size, as it relates to feeding patterns. The miniature whale was alive just a few million years before primitive whales began their evolutionary split into the two cetacean suborders of today: the toothed whales, dolphins and porpoises known as odontoceti, and the baleen-bearing mysticeti, including blue whales and humpbacks.

“The mysticetes tend to be much larger than the odontocetes,” said Geisler. “And this difference is related to their different feeding strategies. Understanding the size of the ancestor of all modern whales helps us understand how these feeding behaviors and distinct body size differences evolved. Tutcetus is one data point in the effort, but it supports the hypothesis that the common ancestor of all living cetaceans was fairly small.”