The Mythological Villain
The Kraken was a mythological giant octopus that would attack ships at sea, breaking the ships and killing and eating the crew. In Jules Verne's 20,000 Leagues Under the Sea, a monstrous octopus killed one of Captain Nemo's men. As early as ancient Greece, octopuses were depicted on pottery, sometimes with sailors, and as recently as today the octopus occupies a villainous role as Ursula in the Little Mermaid.
They are unusual creatures: weird-bodied highly intelligent invertebrates that have numerable means of dealing with threats. But do they deserve their reputation as villains, things to be feared in tales even across the ages?
An alien biology
The octopus has a head with 2 eyes and a beaked mouth, surrounded by 8 arms with suction cups that run down the length of their arms. These cups are sensitive to touch and taste, and are used to help the octopus grip things while it walks. Their bodies are soft, and 90% muscle, which allows them to squeeze into tight spaces. Octopuses breathe using gills. They have three hearts, one larger doughnut-shaped brain, and a mini-brain at the end of each arm.
The smallest octopuses are a few inches in size, whereas the Giant Pacific Octopus can have an armspan of around 14'. Most octopuses live from around 3-5 years. They are solitary creatures that come together for mating; the male uses his one sucker-free tentacle to fertilize the female. Mating is an end-of-life activity for these creatures, as the male dies shortly after fertilizing a female, and the female guards and cares for the eggs until they hatch, at which point she dies. Young are born able to swim and eat, feeding on larval crabs and plankton until they are large enough to go after bigger prey such as mollusks, worms, crabs, small fish, and other octopuses.
Hunting and Escaping
These cephalopods are solitary nocturnal hunters that use their amazing powers to both catch prey and avoid other predators. While they normally walk using their eight arms, most octopuses can use jet propulsion for sudden bursts of movement. Those that lack jet propulsion can use their fins for swimming. They are able to shoot jets of ink or make sudden colorful displays in order to confuse or frighten predators. They can also regenerate their arms, should they lose one escaping. All octopuses have a venomous bite, though only the Blue-Ringed Octopus is fatal to humans.
Masters of Disguise
They are able to change their color and texture to match their surroundings, or even disguise themselves as other creatures. Sometimes they blend into the background in order to catch prey. Some octopuses change their color and shape to appear like things that prey on whatever creatures are nearby, in an attempt to ward off predators. The Mimic Octopus mimics the swimming style of sea creatures that it copies, making the disguise extremely convincing.
Intelligent!
Problem-solving experiments and tests have shown that octopuses have both short and long term memory. They can open jars and are able to use tools, including building defensive forts with rocks or bottle caps they find laying about, creating a sort of armor to protect their undersides with clam-shells, and the Blanket Octopus, which is immune to the man-o-war's venom, even wields tentacles from the portugese man-o-war as weapons.
Octopuses have been known to steal fish from neighboring tanks after escaping their own, spitting water at people they don't like, and one particularly famous one, Inky, escaped his partially open tank to cross an aquarium and go down a 50' drainpipe to freedom.
Conclusion
Have they earned their place as the villains of myth? They are intelligent and rather sneaky, but we think casting them as villains is entirely unfair! Unless you're a small fish...
Trivia
Two common misconceptions put to rest: 1.) The plural of octopus is not actually octopi; it's octopuses, and 2.) It's arms are not technically tentacles, tentacles being cephalopod arms that only have suction cups on the tips.