At Marine Mammal Laboratory, laboratory director Herman put a dolphin through its paces. Using hand signals, Herman asked, "Is the ball in the pool?" The dolphin correctly pressed a lever（杆）for "YES". Herman asked it to push the ball to a basket. It did. Then he signaled his pupil to do it again, but he removed the basket. Herman expected the dolphin to be confused. Instead, it carried the ball to the NO lever and stopped there. Herman was astonished. "This is a totally untrained, invented response," he said, "We never dreamed the animal would ‘think' the problem through like that."

To get a closer look at these amazing creatures, Herman and his team spent a week on board the Jennifer Marie. Whenever they heard the cry "Dolphins!" they slipped into the water. The dolphins approached, curious about them, observing them with dark, liquid eyes. Dolphins love to imitate. If they swam on their backs, Dolphins did too. If they dived, Dolphins followed. This talent can be carried to extraordinary lengths. In one instance, a trainer blew a puff（泡）of cigarette smoke against the window of an observation tank. A young dolphin rushed to its mother, nursed briefly, and spat（吐）out a cloud of milk against the glass.

Herman said "We're still in the early stages of learning about the intelligence of these animals and our ability to communicate with them." Scientists are amazed at dolphins' intelligence, but fear for the future of these trusting ocean creatures.

Dolphins' trouble could be sharks, killer whales or, worse yet, a fishing vessel. Indeed, in the past three decades, commercial fishing, especially the biggest threat—the drift net fishing, has greatly decreased the world's dolphin population. Every night in the North Pacific, hundreds of Asian fishing vessels put out these "curtains of death," each up to 50 miles long. Floating with the currents, they sweep up all sea life in their path. People wonder what the world would be without dolphins.