Research Overview:
The objective of this study was to determine if bottlenose dolphins could detect an oil slick on the surface of the water. In the initial experiment, the dolphins viewed a transparent cylinder and learned to press a paddle when they detected something in the cylinder besides water. It was demonstrated that dolphins could discriminate between oil and the uncontaminated surface of the water.
This project also showed that dolphins would avoid an oil slick, as they would hesitate to swim beneath one when detected. Their few contacts with the oil (either accidental or as part of an investigative process) resulted in an overt startle response, which set a pattern for subsequent avoidance.
Overall, the dolphins avoided oil both during the day and at night, although the response broke down when the threshold of their ability to detect the oil was reached. Visual cues were instrumental in the dolphins’ detection of the oil, and tactile sense played the most important role in their response to the oil. Memory of its location influenced their behavior, even after the oil was removed.
