Photo: Solvin Zankl
The porpoise is sent back and forth in the basin depending on where fish are thrown into the water. The experiments are carried out both with and without suction cups over the eyes to study the significance of sight and echolocation during the pursuit of the prey. These studies have provided a detailed understanding of how porpoises make use of and adjust to the sounds during the prey-hunting sequences. These factors have never before been documented in any whale species to this degree of detail. The results can also be used to better understand how porpoises catch their prey and hopefully how porpoises can avoid getting caught in fishing nets as they pursue their prey.
The inter-click intervals from a porpoise while pursuing prey are shown on the left. The fish is caught at the time “0". Modified from: Verfuss et al. 2009, Journal of Experimental Biology 212: 823–834. On the right, notice how the source strength (ASL: acoustic intensity counted back to a distance of one metre in front of the animal) declines the closer the porpoise gets to its prey. Modified based on Atem et al., 2009, Bioacoustics 19.1: 49–65.