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Marine Mammal Hearing
Research with Dr. Darlene Ketten

Dr. Darlene Ketten uses computerized tomography (CT) and magnetic resonance imaging (MRI), along with traditional physical dissections, to get detailed information about the hearing structures of animals. In the image below, Dr. Ketten is preparing a harbor porpoise for a CT scan.

Dr. Darlene Ketten
Dr. Darlene Ketten prepares a harbor porpoise for a CT scan. Photo by Tom Kleindinst, Woods Hole Oceanographic Institution.

She often also performs a dissection of the animal to obtain microscopic details about the hearing structures.

Dr. Ketten (right) and assistant Sarah Marsh prepare to dissect a harbor porpoise
Dr. Ketten (right) and assistant Sarah Marsh prepare to dissect a harbor porpoise. Photo by Tom Kleindinst, Woods Hole Oceanographic Institution.

Dr. Ketten combined the data she collected from the CT scan, the MRI image, and the dissection to create a three-dimensional model of the harbor porpoise's head. With these data, she is able to hypothesize about what and how the animals hear.

Image of harbor porpoise skull with insets showing details
The combined data obtained for a harbor porpoise are shown in this image. Four cross-sectional views of the head were obtained from a MRI and are shown in orange. A 3D reconstruction of the same animal's skull was created from a CT scan and is shown in gray in the middle of the image. By combining the data from the MRI and CT scan, the position of each cross-sectional view along the animal's head can be shown, as indicated by the yellow arrows and boxes. Image by Dr. Darlene Ketten, Woods Hole Oceanographic Institution.