Armed but not dangerous: is the octopus really the invertebrate intellect of the undersea world?
Frequently, we humans look down on invertebrates as inferior forms of life. But at least one invertebrate, the octopus, may possess enough brainpower to alter this biological prejudice. Octopuses are mollusks, like snails, clams and oysters, but they are smarter, nimbler, more curious and more resourceful than any oyster. They have to be: Like their fellow cephalopods, squid and cuttlefish, they lost their external shells millions of years ago, but what they lack in armor, experts say, they make up for in brains. The central nervous system of the octopus is among the largest and most complex in the invertebrate world, rivaling that of many vertebrates, including birds and fish. How intelligent that nervous system makes the octopus is still a matter of scientific debate, however. Over the years, scientists have tested octopus intelligence by teaching captive specimens to slither through simple mazes and to tell squares from crosses. Octopuses even learn to unscrew lids to get at food. T
