|While wearing eyecups, Tanner still successfully imitates DRC Co-Founder Mandy Rodriguez's "shark" behavior.|
In 2010, Dolphin Research Center (DRC), a leader in dolphin cognition research, scientifically demonstrated that dolphins can imitate without using their eyesight. A recently published follow-up study now not only reveals that these intelligent marine mammals achieve this task by using sound, but that they employ a deliberate, problem-solving approach to imitation. In the original study, a dolphin wore soft, latex eyecups to block its vision and then imitated another dolphin. To determine if sound was indeed used to accomplish imitation, for this new study the “blindfolded” dolphin was asked to imitate a human’s movements in the water. The study, called Switching Strategies: A Dolphin’s Use of Passive and Active Acoustics to Imitate Motor Actions appears in the online edition of the journal Animal Cognition (February 2013). A video produced by DRC about the study can also be viewed at DRC's YouTube channel by clicking here.
“We had to change the way that behaviors sound to a dolphin to see if that affected his ability to imitate,” explains Dr. Kelly Jaakkola, DRC’s Director of Research. “Clearly when a person moves in the water, he sounds very different from another dolphin.” Throughout testing the human modeled a variety of motor behaviors such as bobbing up and down, swimming while kicking feet together, spinning in a circle or even swimming like a fish with legs and feet moving side-to-side. The dolphin, a young male named Tanner, successfully imitated the behaviors with a high rate of accuracy.
Confirming that the dolphin did indeed use sound was exciting in itself, but how he used sound was even more intriguing. During testing, in addition to visual observation and video recording, the research team also used a hydrophone – an underwater microphone – to record what happened beneath the water’s surface. “When imitating a dolphin, Tanner recognized the characteristic sound of the behavior, much like people might recognize the sound of hands clapping. When imitating the less-familiar behavior of a human in the water, he switched strategies and used echolocation a whole lot more,” Dr. Jaakkola elaborates. “Dolphin echolocation is not typically on. It requires a decision on the part of the dolphin to activate it, which shows that Tanner wasn’t just mindlessly acting. He was flexible enough to change his approach to gather the information he needed. In other words, he actively problem-solved.”
Realizing this provides new insight into the dolphin mind, but the implications are even more far-reaching. “Scientifically, studies like this are really important because so far, only humans and dolphins have shown this kind of flexible skill with imitation. But humans and dolphins are separated by about 90 million years of evolution. This means they must have evolved these skills separately. So exploring imitation in dolphins and humans can teach us not only about each individual species, but also has the potential to fill in crucial information about why the ability to imitate ever evolved at all,” believes Dr. Jaakkola.
Dolphin Research Center’s research continues to add to the world’s knowledge database on dolphins. In addition to this study and its predecessor, Blindfolded Imitation in a Bottlenose Dolphin (Tursiops truncatus) which appeared in the International Journal of Comparative Psychology (Volume 23, No. 4), DRC’s research demonstrated for the first time that dolphins can understand numerical concepts and explored what dolphins understand about hidden objects. Throughout the years, the center has been involved in numerous other observational, cognitive, and husbandry research projects and papers, both on its own and in cooperation with other well-known scientists and institutions. These include studies on immunology, DNA fingerprinting, metacognition, language research, signature whistles, calf independence and others.