Whitlow Au - Early Navy Work

Early Navy Work

Upon completion of his Air Force service, Whit was recruited and hired as a new professional at the Naval Undersea Center in San Diego, California. Part of the new professional program was to expose newly hired professionals to the various types of programs going on at the San Diego Laboratory and also at its "skunk works" facility on the Kaneohe Marine Corps Air Station in Hawai'i. Being Hawaii-raised, Whit took the opportunity to step down out of the ionosphere and to take a quick look toward the ocean at the biosonar or echolocation performance of the Navy's "secret" dolphins. It can't be said for certain how much Whit's fascination for understanding the dolphin's echolocation, or his love of the Islands, influenced his decision, but he decided to join the biosonar research group at the Hawaii Laboratory of the Naval Undersea Center. He then was quickly advanced to the head of its Biosonar Branch.

Au's first paper on the echolocation of dolphins surprised a few people. He, along with physicist Bob Floyd and biologists Earl Murchison and Ralph Penner found that typical dolphin echolocation signals in the open water had average durations near 40 microseconds with peak energies between 120 and 130 kHz, much higher than the previously reported energy peaks centered at 35 to 60 kHz. That report did much to explain why Scott Johnson had earlier found that bottlenosed dolphins heard sounds up to 150 kHz, but only later did Au report that the previously reported lower peak energy clicks were typical of animals in pools while higher peak energy signals were typically found in the open waters when the animals were looking for small targets a good distance away. That paper also began a precise and methodical examination of the echolocation of dolphins and other small whales carried out by Au that has served to establish, describe, and quantify the echolocation performance and signal characteristics of animals that echolocate under water.