With it's 8 menancing looking arms, it's not surprising that sailors of the past used to fear the Octopus and called it the Devil Fish.
Why did i choose to blog about the octopus out of all the many other interesting animals out there? My interest in them can be attributed to my favourite show, the "Pirates of the Caribbean". Perhaps it is a coincidence that the "villain" of the show, Davy Jones, had facial features that resembled an octopus. Or yet by chance that the monsterous sea creature, the Kraken, really looked like an oversized octopus. That really sparked off my interest in this mysterious underwater creature...
Image (Above) of Captain Davy Jones, taken from http://www.sfgate.com
Image (Above) of the Kraken sinking a ship, taken from http://en.wikipedia.org/wiki/Kraken_%28Pirates_of_the_Caribbean%29
But yet, was it really an Octopus that Davy Jones and the Kraken resembled? Perhaps it was a squid instead of an octopus! So what is the difference between Octopus and Squids? While they may appear to be similar, there are some fundamental differences. The major distinction would be that the suckers of squid are armed with hooks or sucker rings, sometimes both; while octopuses have simple suckers without secondary armature. However, today I would be concentrating on the Octopus instead of the squid.
The Octopus, refers to creatures belonging to the genus, Octopus. To date, there are around 300 recognized octopus species in the world.
Image (Above) of the Common Octopus, Octopus vulgaris, taken from http://en.wikipedia.org/wiki/Octopus.
So... are Octopuses as scary and terrifying as the old sailors made them out to be?
Unlike sharks, they do not have razor sharp teeth. In fact, octopus do not even have a protective outer shell to protect if from predators. Majority of octopuses have almost entirely soft bodies with no internal skeleton. This sure makes it seem like an easy meal to swallow!!
Yet, how have these sea creatures eluded their predators and instead become excellent hunting machines?
Certainly, their mascular eight arms allow them to put up a tough fight against predators. However, not all battles can be won and when you can't beat them, run! And that's certainly an easy task for the Octopus whose body structure allows them to escape to safety by squeezing through very narrow cracks between underwater rocks where predators cannot follow. Even a 600 pound Octopus can pass through a tight passageway no larger than the size of a quarter coin.
Exactly how flexible are these creatures? You'd have to see it to believe it.
Watch how the octopus gets out of a tight situation.
Watch the Octopus escape through an one-inch hole!!
Other defensive mechanisms employed by the Octopuses include the usage of camouflage, mimicry, ink sacs and autotomising limbs.
Camouflage:
A very important tactic to avoid detection by predators, is the use of certain specialized skin cells which can change the apparent color, opacity, and reflectiveness of the epidermis. When possible, Octopuses prefer to aviod head-on confrontation with their enemies and prefer to remain unnoticable. They been observed to have the ability to adopt different textures, (such as those of a seaweed, uneven coral reef, bumpy rocks) of their mantle in order to reach the highest stage of blending in with the environment.
Image (Above) of an Octopus blending into it's surroundings, taken from http://hmpadventures.dk
Watch this video to see the shape-shifter and colour-changer perform its magic.
Mimicry: Certain species of Octopus, go a further step to combine their highly flexible bodies with their color changing ability to allow for the accurate immitating of some of the most dangerous sea creatures such as the lionfish, sea snakes and eels. By adopting the posture or movements of the lionfish or sea snakes, the mimic octopus deters enemise from eating it as fishes do not want take the risk of eating the wrong thing.
Image (Left) of a Mimic Octopus imitating a Lionfish, taken from http://www.michaelaw.com
Image (Right) of a Lionfish, taken from http://www.amnh.org
Are they successful at imitating other sea creatures? You be the judge.
Ink sacs: If spotted by their enemies, most octopuses eject a jet of thick blackish ink to allow for their escape by blinding and confusing their enemies. This ejected ink goes a further step to dull smells which is very useful for evading hunters that rely on their sense of smell, like sharks.
Image (Above) of an Octopus ejecting ink, taken from http://encarta.msn.com/media_461532742/octopus_ejecting_ink.html
Autotomising limbs: If everything fails and an octopus is unable to break free from a predator's attack, some octopuses can detach their own limbs at their own will, similar to how lizards drop their tail to escape from predators. The Ameloctopus is one such species who employ such evasive tactics.
Watch the video to have a better look at the Ameloctopus in action!
http://video.nationalgeographic.com/video/player/animals/invertebrates-animals/octopus-and-squid/octopus_amel.html
Please do not be fooled into thinking that an Octopus is only capable of elaborate defensive techniques. Instead, the Octopus is able to leverage on such capabilities to change its status from the hunted to the hunter.
Their flexible body structure allows for them to explore tight corners and deep crevices to look for food. Not only can their colour-changing, shape shifting ability be used for predator evasion, it can also be used to sneak up on unsuspecting prey. The squirting of ink can also be used to confused their prey and prevent them from escaping. This speaks volume of the versatile nature of this sea creature.
AVP? Not exactly. In the battle of the Shark versus the Octopus, who would emerge victorious?
Can the defense tactics of the Octopus protect it from the prowling Shark?
Find out here!
Ever wondered how intelligent Octopus are?
It has been argued that they are probably the most intelligent invertebrates around. Although unable to tell the depth of their intelligence and learning capability, the usage of mazes and problem-solving experiments has revealed that Octopus do have both short and long- term memory. Laboratory experiments also observed that Octopus are possibly capable of observational learning. An experiment in 1992 by Graziano Fiorito and Pietro Scotto highlighted the possibility that Octopus had the potential to learn by watching. Although strongly this theory was contested by many, it does remind us of the endless possibilities of the true intelligence of the Octopus.
"An octopus in a German zoo has learned to open jars of shrimps by copying staff - and is now showing off her skills to visitors."
Read the full articule here: http://news.bbc.co.uk/2/hi/europe/2796607.stm
References:
"Armed But Not Dangerous," by Doug Stewart. National Wilflife, Vol. 35 No. 2. Feb/Mar 1997.
http://animals.nationalgeographic.com/animals/invertebrates/common-octopus.html
http://en.wikipedia.org/wiki/Octopus
http://encarta.msn.com/media_461532742/octopus_ejecting_ink.html
http://hmpadventures.dk
http://news.bbc.co.uk/2/hi/europe/2796607.stm
http://video.nationalgeographic.com/
http://www.amnh.org
http://www.lookandlearn.com
http://www.sfgate.com
http://www.tonmo.com/science/public/giantsquidfacts.php
http://www.youtube.com