At three hundred feet, we are profoundly changed. The pressure at these depths is nine times that of the surface. The organs collapse. The heart beats at a quarter of its normal rate, slower than the rate of a person in a coma. Senses disappear. The brain enters a dream state. At six hundred feet down, the ocean’s pressure—some eighteen times that

The very same qualities that have made the “domestic fishes” famous in China have made them infamous in the United States. A well-fed grass carp can weigh more than eighty pounds. In a single day it can eat almost half of its body weight, and it lays hundreds of thousands of eggs at a time. Bigheads can, on occasion, weigh as much as a hundred

In effect, that pioneering orca induced “tonic immobility” in its adversary—a temporary state of paralysis many species of sharks fall into when turned on their backs. The human discovery of tonic immobility in sharks is relatively recent, making the orca’s behavior all the more remarkable.