Cetacean Hybridization

Heather R. Zornetzer, B.A., Deborah A. Duffield, Ph.D.

Department of Biology
Portland State University
PO Box 751
Portland, Oregon 97207

A review of interspecific and intergeneric hybridization events among Cetaceans is presented here. A summary of the literature reveals that the nature of reproductive barriers within both the suborders, Mysticeti and Odontoceti, is not well understood. Consequently the evolutionary significance of natural hybridization and introgression as it relates to speciation is still under debate and certainly warrants further rigorous inquiry.

In order to understand the evolutionary significance of natural hybridization among Cetaceans we must first be able to detect levels of hybridization and introgression in wild populations. This requires the development of effective, reliable diagnostic tools that can be applied in the field to identify putative wild hybrids. Three case studies of recent Odontocete hybridization events in captivity are presented here to highlight a multidimensional methodology that has proven useful in characterizing F1 and B1 hybrid individuals for crosses between Tursiops truncatus x Delphinus delphis and Tursiops truncatus x Pseudorca crassidens.