Bottlenose dolphins process information both visually and acoustically. They're able to recognize and respond to pictures they see on underwater television screens, a talent that chimpanzees struggle with unless they've received extensive training. Scientists say that the dolphin's ability to understand hand signals from a trainer on a screen as well as it does from a live trainer demonstrates abstract thinking skills.
Where do dolphins get these higher-thinking skills? Part of it may come from brain size -- and dolphins' brains are comparable to those of humans. That is, the brain takes up about 5 percent of the dolphin's body weight and uses about 20 percent of its metabolic energy [source: University of Michigan]. Dolphin brains still don't match their head sizes, however. Most of the dolphin head is made up of fat.
Chimpanzees tend to be challenged with understanding the purpose of pointing, but bottlenose dolphins usually understand the gesture when humans use it. This is perhaps all the more impressive because they don't actually have arms, which could suggest advanced body-mapping abilities. What's more, some research has shown that dolphins can plan. In a training study, two dolphins were given a command of "tandem, create." The pair dove under the water, appeared to communicate and then leapt out of the water next to each other simultaneously. The animals previously had been taught the meaning of the create sign when trainers rewarded them for coming up with novel tricks or behaviors when trainers gave the sign. In the pair demonstration, they planned a novel activity together [source: Dingfelder].
The pair activity brings to mind one theory for why both chimps and dolphins are smarter than your average mammal: Both animals -- like humans -- rely heavily on social systems. Male dolphins even hang out in small groups and work together to attract and herd female mates. Not all primates form such complex social systems -- orangutan and gorilla systems are not as complex as those of dolphins, other primates or humans, of course.