Slide 22 of 37
Notes:
Animals allow us to gain perspective on sensory and perceptual processes when we investigate animals with unique sensory systems. For example, both bats and dolphins use a kind of biological sonar (called echolocation, though it is used for much more than just location). Like bats, dolphins obtain information about the identity, location, and characteristics of objects in their world by actively interrogating them using their unique biological sonar. Unlike bat biosonar, dolphin sonar is highly adapted to their aquatic environment. Bottlenose dolphins (Tursiops truncatus) send very brief, broad-band, high frequency clicks, which emerge from the rounded forehead or melon as a highly directional sound beam with 3 dB beamwidths of approximately 10 ? in both the vertical and horizontal planes. The echolocation clicks have peak energy at frequencies ranging from 40 to 130 kHz with source levels of 220 dB re: 1 ?Pa at 1 m. The time between successive clicks depends on the distance between the animal and the target it is scanning. The average time between emitted clicks in a train is typically 15 - 22 msec longer than the time required for the click to travel through the water to the target and return as an echo.
