Although there are over 80 species of cetaceans, studies of their cognition have been almost exclusively focused on the Atlantic bottlenose dolphin, Tursiops truncatus . Because we are able to maintain a healthy population of this species in human care, scientists are able to conduct controlled studies that add to our understanding of the abilities of dolphins to learn, remember, solve problems, and express creativity and intent. They can also discriminate between sizes, shapes, and textures using echolocation.
Dolphins can visually discriminate between shapes in controlled tests.
They can recognize and remember individual animals, people, and places, based on their experiences. They can also indicate if a specified object is not within their vision. For example, in one marine park, the dolphins were rewarded with fish if they picked up trash that blew into their pool and took it to the trainers. One dolphin delivered much more trash than the others. The trainers discovered that the dolphin had hidden a plastic bag under the dock and was tearing off small pieces of it to take to the trainers and get many fish rewards.