National Geographic : 1971 Dec
Changing color at eye-blinking speed, a minutes-old briareus clings to its empty egg case. These photographs, taken only a quarter second apart, show the hatchling's ability to flush brown. The leopardlike spots are chromatophores; tiny muscles radiate from each one, enabling the animal to control their size and, thus, its overall color. Adults of this species can assume shades ranging from deep red-brown to light aqua. shells and have evolved into highly mobile animals. They share with squids the ability to change colors rapidly. Both mollusks also are jet-propelled. They dart swiftly through the sea by ejecting water through a tubular siphon below the head. Octopods have two fewer arms, or tenta cles, than squids. Both groups of cephalopods have eyes remarkably like those of vertebrates in form and keenness of vision. Patience Pays for an Eight-armed Hunter Inhabiting all oceans at all latitudes, octo puses dwell as deep as 17,000 feet. In the Antarctic, individuals of the same species range from shallow surface waters to depths of more than two-and-a-half miles. Few, if any, other living creatures match this adaptability. Most octopuses are voracious predators, 786 ambushing crabs, clams, shrimps, and many other marine animals from holes and caves, crevices and burrows. An octopus is patience personified; I've seen one sit for hours on a coral head waiting for prey. When an unwary crab showed up, the octopus whipped out an arm and immobilized its victim with hun dreds of suckers. Rarely in nature is an octopus seen in the act of eating. But I've found crab shells com pletely empty of meat, with only the tiniest of punctures. The octopus apparently bites out a small piece of shell with its parrotlike beak. Then it injects a poisonous salivary fluid that almost liquefies the flesh, making it easy to suck out (page 791). Octopuses, again like squids, are mottled with myriad pigment sacs, or chromatophores, which they consciously control to change color. The adult of a familiar Florida species, nvuHn v c y mc r->ccU iv.