Animal trainers at aquariums and marine parks train dolphins to jump anywhere from 15 to 30 feet above the water to put on a show for audiences. Dolphins jump in the wild also. Biologists have determined several reasons for this behavior, although dolphins also seem to jump sometimes for no practical aims whatsoever.
Different species of dolphins have varied jumping abilities, with the Pacific white-sided dolphin probably getting the grand prize for height. At the John G. Shedd Aquarium in Chicago, these dolphins are trained to jump 30 feet above the water. The widely-recognized bottlenose dolphins put on good shows too. At the National Aquarium in Baltimore, for example, bottlenose dolphins are trained to jump 18 feet.
Trainers use operant conditioning, a psychological method, to train animals using positive reinforcement. When trainers see a dolphin engage in certain behavior they want it to do in shows, the trainers reward the animal with anything they know it likes, such as fish or toys. This prompts the dolphin to do the specific behavior more often. Training a dolphin to jump begins with lowering a buoy or brightly-colored ball to the water. The curious dolphin swims over to check it out and is rewarded with a fish. This intelligent animal learns that touching the object brings a fish, and over time, the trainer raises the buoy to greater heights so the dolphin needs to jump to touch it.
In the wild, other dolphins, such as spinner, spotted and Commerson's dolphin, all can jump high as well. Researchers at the Wild Dolphin Foundation, note that they have seen spotted dolphins jump as high as a boat's tuna tower, which would typically be at least 15 feet high.
Dolphins jump in the wild for several reasons. When traveling, they use less energy jumping than swimming, because water is more dense than air. Dolphins can move a long distance with one long jump, especially with their streamlined bodies. Dolphins also jump to find food, similar to how birds look for fish above the water. In addition, they will jump to scare a school of fish, which then pack tighter into a group, and the dolphin can catch several at once.
Dolphins communicate with other dolphins by jumping and become particularly acrobatic during mating season. Male dolphins often do complicated spins and flips, perhaps to attract females, or to show dominance that keeps other males away. Biologists also theorize this behavior might be playfulness in the courtship ritual.
It seems that some jumping behavior is simply for fun. At the Red Sea Dolphin Reef in Eilat, Israel, tourists can watch captive dolphins that are kept in a more natural habitat than aquariums or zoos. At this facility, dolphins live in a nature reserve bound in by nets, where they play, hunt and socialize, similar to how they would live in the wild. They are free to completely ignore the tourists if they prefer, and do not receive food as a reward for performing. Nevertheless, the dolphins approach the guests in a friendly manner, jump for them,and play with the staff, all apparently out of enjoyment.