What Do Sharks Eat?

The body of an octopus is remarkable enough. The common octopus, O. vulgaris, has eight armlike appendages, three hearts pumping blue blood, an ink-based defense mechanism, and highly developed jet propulsion. An octopus can change size, shape, texture, and color at will, and all at the same time if necessary.

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 poun

The experiment was elegant in its simplicity. Using a toy lion and a toy zebra, Barrett asked each child, “When the lion sees the zebra, what does the lion want to do?” The results were surprising: 75 percent of the three-year-olds in both groups answered with some variation of “The lion wants to chase/bite/kill the zebra.” (It must be remembered t

And while smell can be put to complex uses—navigating the open oceans, finding prey, and coordinating herds or colonies—taste is almost always used to make binary decisions about food. Yes or no? Good or bad? Consume or spit?

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.