The Neatest Little Paper Ever Read ®

Issue 974

(Continued from front page)

• Three-fifths of the neurons of an octopus are located in their arms rather than their brains. When severed, an arm can carry on for several hours as if nothing is wrong. When an octopus loses part of an arm, it can regenerate it in as little as six weeks.

• Octopus eyes are strikingly similar to human eyes. However, there are differences: the octopus can see polarized light which humans cannot; it has wide-angle panoramic views instead of seeing only what’s ahead of it; and each eye can swivel independently. Octopuses are able to keep their eyes in the same orientation regardless of their body position. Sensors keep the pupils balanced as the octopus moves, which allows it to see the same whether it is upside down or right-side up. It also has horizontal pupils, while humans have round ones.

• Human vision can see clearly to the horizon but an octopus can see clearly only about 8 feet away. Furthermore, humans can see in a full spectrum of color, whereas the octopus can see only in shades of black, white, and grey, making it all the more astonishing that its skin can change into so many colors that cannot even be detected by the color-blind octopus. Just as humans are either right-handed or left-handed, an octopus is either right-eyed or left-eyed.

• Scientists recently found that octopus skin contains the same light-sensitive proteins present in octopus eyes, meaning an octopus’s skin can sense and respond to light without information from the eyes or brain.

• Octopuses are expert at camouflage. One researcher witnessed an octopus changing colors 177 times in a single hour. Their skin can change into complex patterns of spots, stripes, and blotches every place on the body except the suckers and the mouth opening. They can even produce “light shows” on the skin in moving patterns that imitate things like passing clouds, which gives the optical illusion of making it look like the octopus is moving when it’s really completely still. It can even control skin texture, while also altering its body shape, in order to mimic other creatures.

• Octopuses change color to indicate mood, with red generally indicating excitement while white denotes relaxation. An octopus presented with a puzzle or a problem undergoes rapid changes in color. The deadly blue ring octopus of Australia will send dozens of electric blue rings all over its body when it is feeling threatened.

• How do you tell a male from a female? Examine the tip of the third right arm. If it has suckers all the way to the tip, it’s female. If not, it’s a male. The tip of the third right arm on the male is kept carefully curled up because the tip is the organ that he places inside the female’s mantle opening in order to deliver a packet of sperm which she stores.

• How do you tell the age of an octopus? You don’t. Growth rate depends on many factors including temperature of the water.

• Over the course of three weeks, a typical Giant Pacific octopus may lay as many as 100,000 eggs, each the size of a grain of rice, shaped like a teardrop, and carefully woven together with a glue-like secretion in a chain resembling braided onions. They hang from the roof and sides of the den, carefully guarded by their mother. They are fertilized by sperm that the father donates, and the mother stores in a gland until it’s needed.

• The ink squirted by an octopus acts as a smoke screen so it can get away from predators, but it also contains substances that affect the predator, including an enzyme that irritates the eyes and clogs the gills, and a hormone that affects circulation. The ink can also dull the attacker’s ability to smell and taste. Scientists were befuddled to find that the ink also contains the “feel-good” hormone dopamine and theorize it may drug potential predators into complacency, while also sedating potential prey. If an octopus is unable to escape its own cloud of ink, it may die.