In situations of great stress in captivity they (dolphins) have been known to commit suicide by starvation, battering against walls, or drowning. -- The Columbia Encyclopedia, 6th Edition 2001-05.
When you consider that dolphins and other whales have been around on this planet for at least 50 million years, compared with much less than a single million years for us human beings, you have to wonder how we got control over them so quickly. They have larger brains than we have. They're bigger and stronger, faster, sleeker and altogether more perfectly formed than we are. And yet, just as we have come to dominate 30 percent of the world (that which is above water) in the short time we've been around, we could say that dolphins and other whales are the dominate species in the other 70 percent, which is water.
The bottom line is that we're both at the top in our separate worlds, cetaceans in their watery domain, we on land. When we scan the horizon for similarities, we have a moment of recognition because we're actually very much alike. We're both mammals, for instance, mammals of a high order for we're both self-aware, and we've both adapted almost perfectly to the world we live in. As mammals we both breathe air, mothers in both worlds suckle their young in loving family groups around which is woven a way of living that fosters social rules maintaining a balance like the golden mean of ancient Greece.