One interesting thing about dolphins is they seem to have a need similar to humans, to feel useful. The aquarium at EPCOT had been gifted with many of the dolphins from a defunded Navy program. They'd been gifted on the condition the dolphins never needed to "work" for their food. But the dolphins hated it. They kept inventing tasks. Finally, the researchers figured that they would just ask the dolphins every time if they wanted to participate. If they didn't, they'd still get fish. But if they did, they'd be useful. The dolphins volunteered almost every day.