Crafty Creatures

Octopuses are known for being sneaky both in the wild and in captivity. They have a knack for creeping up on their prey and disappearing in the blink of an eye, but what enables them to do so? Their main defense tactics are hiding, camouflage, and inking. Their soft flexible bodies and clever thinking allow them to hide in small spaces, and their powerful bodies make them fast swimmers, which is a useful skill when they need to make speedy getaways. An octopus can quickly force water out of its siphon to create a jet propulsion effect, and can travel several miles on this momentum. If they aren't able to avoid a predator's grasp, some octopuses can purposefully detach their own arms in a process known as autotomy. Their limbs regenerate over time, like lizards who undergo autotomy can regrow their tails. The Mimic Octopus (Thaumoctopus mimicus) is unique because it can practice mimicry. They can imitate the appearance and movement of other marine animals such as lion fish, sea snakes, and brittle stars in order to fool both their predators and their prey. If you're interested, this video shows some of their amazing disguises. It's the craziest thing!

Octopuses have a special organ called the ink sac, which produces a dark ink made of melanin. When they feel threatened, an octopus will squirt a cloud of ink as it quickly swims away. The ink can obscure a predator's vision and interfere with their sense of smell, as well as act as a decoy that can confuse an attacker while the octopus escapes.

One thing octopuses are most recognized for is their ability to change the color and texture of their skin. Octopuses do this in order to communicate with other octopuses and blend into their surrounding area. Octopuses contain chromatophores in their epidermis which can emit pigmentary wavelengths of yellow, orange, red, brown, and black. In order to change the texture of their body, they use the many muscles located under their skin. However, it has been speculated upon that octopuses don’t contain all five of these colors. Scientists think that most octopuses have about three of these colors but some can have only two or even four. In our experiments while working with the Two-Spotted Octopus, we found that it was only able to change to about 3 main colors, Red, Yellow, and Brown. We are guessing that this is an octopus that falls under the category of only being able to change to three of the five colors. These specialized skin cells are also said to be able to change the color, opacity, and reflectiveness of the octopuses epidermis. They also utilize this ability to disguise themselves when hunting for food, and strike unsuspecting prey with their long arms and powerful tentacles when they least expect it.

As soon as it catches its food and brings it to its mouth or beak, they give it a deadly, poisonous bite, guaranteeing that their prey is a goner. They then secrete a nerve poison from their beak (cephalotoxin or neuromuscular venom) that stuns their victim. In some cases, their venom can be toxic or even deadly to humans. An example would be the Blue-Ringed Octopus (Hapalochlaena maculosa). These guys can kill a human with their secretion of neuromuscular venom.

(Source: http://marinebio.org/species.asp?id=403)

The octopus would not be the wily wonder that it is without its excellent eyesight, complex senses, and remarkable intelligence These are some of the most fascinating things about octopuses, making them so mysterious and different from any other organism we know, while at the same time somewhat similar to ourselves. Something neat is that octopuses have the ability to taste what they are touching due to the chemoreceptors located in their suckers. Also, something random we didn’t know is that octopuses are actually deaf or have very limited hearing.This, as well as their cleverness in solving puzzles, interaction with people, escape from enclosures, and so much more are just examples of their well-developed brain. Certain maze and problem solving experiments have proven that octopus have both short and long term memory, as well as observational learning by recognizing shapes and patterns. However, octopuses are not able to connect their actions between their arms and brain. For instance, the brain will issue a command to the arms like “Grab this clam” but it is actually the nerve cords in the arms that execute the action not the brain that makes it happen. In a sense it is almost as if the arms have a mind of their own. The brain is not able to receive feedback about how the command was executed but the octopus must instead look with its own eyes to see if their arms followed through with that action. This is definitely a strange concept for us to comprehend; imagine not knowing where your own arm ends!

(Source: http://www.daviddarling.info/images/octopus_eye.jpg)

Octopuses are known to have highly developed eyes but scientists don’t know a whole lot about them at this point in time. We know that the octopus is able to distinguish between different shapes and patterns and we guess that they have some kind of color vision due to the fact that they are able to change color and camouflage their bodies to their surroundings. We do know that they are able to see polarized light. The eye of an octopus is surprisingly very similar to the construction and complexity of the human eye. However the eye of an octopus has photoreceptors in the retina that are directed toward a source of light, this being classified as a “direct” eye. They seem to have almost more efficient eyes than us humans in theory, due to their ability to have a wider field of clear vision, better resolution, and sensitivity to light. Comparing the octopus eye to a camera lens helps put it function into perspective. In a camera, the lens has a fixed focal length. Well, an octopus eye is like a camera, its eye lens also having a fixed focal length. However, the octopus is able to manipulate its entire eyeball to focus instead of just the lens alone. A typical vertebrate only has the capability to focus its lens.


Research from:
Cephalopod Behaviour, by Roger T. Hanlon & Roger B. Messenger
Tales from the Cryptic: The Common Atlantic Octopus, by Nadia Meyers (http://www.dnr.sc.gov/marine/sertc/Featured%20Species%20O%20vulgaris.pdf)
http://news.nationalgeographic.com/news/2001/09/0920_octopusmimic.html
http://www.octopus.com/anatomy/http://animals.nationalgeographic.com/animals/invertebrates/common-octopus.html
http://www.bio.unc.edu/faculty/kier/lab/research.html
http://marinebio.org/species.asp?id=403
http://www.factsmonk.com/octopus_facts
http://www.wikipedia.org/