Research Training Program

Malik Menefee
University of Maryland
College Park, Maryland

Clayon Ray, Ph.D.
Supervising Scientist
Department of Paleobiology

Implications of the Cranial Evolution in the Sperm Whales

This research focused on a study of the cranial modifications of the skulls of both fossil and recent sperm whales and what assumptions can be inferred about their feeding behavior, ecology, and paleoecology. Various measurements were taken on each of the specimens in order to draw inferences of the degree to which the spermaceti organ of these whales were developed. The presence or absence of maxillary teeth and the size of the temporal fossa of each skull were also noted. From this analysis of the sperm whales' skulls, it was noted that in the sperm whales with functional maxillary teeth there were two other characters associated with the teeth: very large temporal openings and a narrowing of the rostrum distally. These characters further distinguish them from the sperm whales which lack functional teeth in the upper jaws. The sperm whales without functional teeth in the maxilla had a broader distal portion of the rostrum and small temporal openings. It is suggested that the feeding behavior of these two categories of sperm whales were very different. These features in the skull may be correlated to the development of a large spermaceti organ.

This research was supported by a grant from the National Science Foundation Research Experiences for Undergraduates Program ( Award: DIR-9200203).