So that's it! We had a lot of fun researching and interacting with our favorite marine animal. We would like to thank Judit Pungor for all her help during our project. Our experiment would not have been possible without her!
On a final note, here are some fun pictures we took while visiting the lab!
The tupperware container where the baby Two-Spots are kept, with shells and other knick knacks.
Close up of our test subject under orange light.
The little Two-Spot hiding in a corner during exposure to blue light.
View of the school's small private beach, with a cool view of the aquarium in the background
Some cormorants on a rock
One of the buildings at Hopkins.
An awesome giant squid sculpture on the ceiling of Judit's lab!
We returned to the lab the following day to conduct our second experiment. Our plan was to put a baby octopus in the same clear plastic container we had used the previous day, let it adjust to the new environment, and then observe its responses to different colors of light. We did this by turning off the lights, covering the top of the container with colored tissue paper, and shining a flashlight down from 12 inches away. We anticipated that the light source we used could sway our results, so we brought four flashlights from home and tested them all to see which one best suited our experiment; we chose one that let out an even white light that wasn't so bright that it would surprise the octopus too much.
After a few minutes of trying to get the octopus into the test container, Malwina stuck her hand further into the container to get a better angle, but the stubborn octopus darted right past the shell and onto her hand.
Before starting, we watched the octopus under regular light for a few minutes and saw that it didn't change much from a dark brown color. Then we turned off the lights and the three of us adjusted to the dark for about three minutes. To set up a control, we turned on the flashlight without using any tissue paper. Under this focused plain light, the octopus was a noticeably lighter shade of brown.
We began our experiment with red. However, once we started we quickly realized that under different colors of light it was difficult to observe any change in the octopus's skin color. Everything just looked red! After a few moments of standing there unsure of what to do next, we noticed with relief that we could still see when the octopus became dark or light. It was a little difficult to see even with out faces inches away from the container, so we hope our description makes some sense! If you haven't seen it before up close, when an octopus changes color it looks almost like a dye has flushed its skin in a split second.
So we resumed our experiment with a new approach. We would first observe the octopus under the light for 2 minutes, and see the color it had turned by quickly lifting the paper. Unfortunately, our results seemed to reflect the same responses, so we concluded that our method was ineffective for this kind of experiment. Darn! But trial and error is part of being a true scientist, so we were not too disappointed.
On Tuesday April 27, we went back to Hopkins to conduct our first experiment. Judit let us use the lab's baby Two-Spot Octopuses (Octopus bimaculoides) which were about 2cm long. This made things much easier for us because they were less likely to leap out of their containers and make a run for it, like the Red Octopus had tried to demonstrate for us during our previous visit. After picking an octopus, we scooped it out of its tupperware home and put it in a clear plastic container half filled with sea water (which you can see behind the colored paper in the picture below). The little guy must have been a little surprised, because he let out a cloud of ink that was bigger than he was. We let it adjust to the new environment for about ten minutes, and began our experiment.
We used ten different colors of construction paper, which we had laminated to prevent from getting too damp. These were placed under the container one at a time and left for two minutes to allow the octopus to get used to the change and let us observe its color changing behavior. We decided to stick to describing the overall color of the octopus, as the variety of patterns it displayed could confuse our results.
Since the table top we were working on was black, we used the black paper as the control for our experiment. With this background color, we observed that the little octo was a dark reddish brown color and did not changeat all during the two minutes.
We decided it would be best to alternate between dark and light colored paper, so we chose white as the next background. The moment we placed the container over the paper, the octopus immediately turned pale. We were a little surprised by how quick the change was! As the time passed, we noticed that the octopus would flash reddish brown if we made a sudden movements.
The next color we tested was brown. We noticed that the octopus adjusted quickly to the new background again; this time, it turned completely brown, and would gradually fluctuate between dark and light shades.
Then we tried the pink paper. After the brown shades we observed with the previous color, the pale red skin of the octopus was easy to notice.
With the orange background, the octopus turned brown and remained so with little change. Halfway through the time limit for the color, it surprised us by turning completely orange. If the test environment had some clutter to hide among, we would have had a hard time spotting the little guy.
On the green paper our little friend became reddish brown and sometimes turned a pale brown yellow color. It would also flash different shades of brown from time to time.
Then we tried the red paper. The octopus was first orange but changed to a dark reddish brown.
On the blue paper, the octopus seemed a little hesitant. It remained a pale orange tan color, but would sometimes pulsate with an earthy brown color.
With the yellow paper, the octopus was initially brown but changed to pale orange. Its skin closely matched the color of the paper, and would likely be an effective disguise in the wild.
The final color we tried was purple. The octopus was a brownish red color for the entire two minute time period, but occaisonally the sides of its body would remain brownish red, while the top of it would change to a pale brown.
We noticed that the octopus would occasionally show multiple colors at once. Its most frequent patten was to make the center of its body pale with a crusty appearance, while its sides turned dark brown. While displaying this pattern, it would try to remain still and sometimes sink to the bottom of the container.
Because young octopuses only have a fraction of the fully developed chromatophores they will have as adults, we were only able to observe basic color change and patterns. It would be interesting to try this same experiment on an adult Two-Spot to see if mature chromatophores allow more complex responses.
We decided it would be fun to film the octopus and share our point of view, but unfortunately an assortment of technical difficulties prevented us from getting footage of the first half of our experiment from the camera to a computer. Bummer! Luckily we filmed with two cameras, so here's a short video of the cute little octopus, starting with the green paper. Enjoy!
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!
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/
So as many of you may know, octopuses belong to the phylum Mollusca. Members of this phylum are bilaterally symmetrical soft-bodied invertebrates with some form of hard shell. They each have a nervous system, an open circulatory system, and a complete digestive tract. In case you were wondering where octopuses fit in the grand scheme of life, here's the scientific classification:
Domain: Eukarya
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Genus: Octopus
Their closest relatives are cuttlefishes, squids, and chambered nautiluses, which are all of the class Cephalopoda. So far, about 700 species of cephalopods have been discovered (Hanlon & Messenger). Unlike their fellow cephalopods which all have some sort of shell structure either externally (like the shell of a nautilus) or internally (cuttlefish have a cuttlebone that helps with buoyancy, and squid have a long thin pen that supports their bodies), the only hard part of an octopus's body is their beak. This enables them to squeeze into unusually small spaces, as long as the opening is larger than their beak.
(Source: http://www.octopus.com/anatomy/)
To refresh your memory, an octopus has a head, a mantle, and eight arms. The beak, eyes, and complex brain are all located in the head. The mantle holds the octopus's internal organs, such as its digestive tract, kidneys, and three hearts. One heart pumps blood, which is actually blue, throughout the octopus's body. The other two hearts, known as the branchial hearts, pump blood to the gills where they absorb oxygen as water flows into the mantle. This water is then forced out of a tube called the siphon.
Each arm has one or two rows of suckers along its entire length. These suckers are connected to nerves, which enables the octopus to use them to grab and taste food and other objects. A Giant Pacific Octopus (Enteroctopus dofleini), which is the largest octopus in the world, has two rows on each arm and can have about 1,600 suckers total (FactsMonk). That’s a lot of suckers! Octopus arms are muscular hydrostats, which makes them very strong and flexible. This helps them catch and kill large prey, and even perform some of those escape artist tricks they are known for, such as lifting a heavy lid off of their tank. Muscular hydrostats are basically a mass of muscle that act as skeletal support would in another animal. However, instead of a rigid structure that restricts certain kinds of movement, the muscular hydrostats can bend, elongate, shorten, and twist at any part, even at several parts all simultaneously. This is the same structure that makes up a worm's body, an elephant's trunk, and our tongues!
Speaking of tongues, octopuses have a radula, also known as a rasping tongue, inside their beaks. The radula has tiny little teeth that scrape food into smaller pieces before swallowing. Octopuses eat mainly crabs, crayfish, and mollusks, including other octopuses. Their predators are seals, sharks, dolphins, eels, and humans. Octopuses are a delicacy in many cultures, especially in Japan, Portugal, the Mediterranean, and Hawaii, and are sometimes eaten alive. According to the USDA, octopuses are actually a good source of B3, B12, potassium, phosphorus, and selenium, but we prefer to think of them as friends rather than food!
Sadly, octopuses typically don’t live very long lives; on average their life span is only about one to two years. The Giant Pacific Octopus is the longest-lived; males live to approximately 4 years and females to about 3.5. Males die after mating, and females die shortly after their eggs have hatched. Information for how many eggs an octopus lays is extremely varied but from what we have gathered it seems that they can produce a couple thousand to about two hundred thousand. It seems to depend on the species and individual. The female usually hangs her eggs in strings coming down from the ceiling of her little haven or she individually attaches each egg to the substrate, once again, this depends on the species. The female has a tough life caring for her soon to be born babies. She spends her time guarding them from predators and blowing small currents of water over the eggs so that they are able to get enough oxygen. The female octopus also does not hunt at all during the approximate one month period that she takes care of her eggs and may even ingest her own arms for sustenance! When her eggs finally hatch, mom leaves her little haven but she is extremely weak due to not eating, therefore causing her great vulnerability. She dies soon after her eggs hatch anyways but she is more likely to be eaten by a predator since it is unlikely she will be able to defend herself. Octopuses are not social animals in that they don’t have contact with their mother or learn skills from her. Octopus learn on their own and don’t have any influence from parents or siblings. After her little babies hatch out of their eggs, the young larvae spend their beginning stages of life drifting in clouds of plankton at the surface of the ocean. While drifting they are able to feed on copepods, and larval crabs and starfish. They eventually descend back to the bottom, returning to the deep, but only if the babies are lucky enough to survive the treacherous plankton cloud. In this cloud they are very vulnerable to other plankton eaters. As adults, octopuses live on the ocean floor. One thing we thought was pretty neat is how octopuses will sometimes collect random objects like coconuts or crustacean shells that they come across along the seafloor, and make little homes out of them.
You can find octopuses in all the oceans of the world. The Giant Pacific Octopus, which we have here in our aquarium, is found along coastal waters of the North Pacific. Another species found in Monterey Bay is the Red Octopus (Octopus rubescens). Hopkins Marine Station has an adult Red Octopus, which was caught by one of the lab's scientists when he was diving. However, due to its wild and quirky behavior this little guy can be pretty tough to work with, so we're lucky that the lab also has baby Two-Spot Octopuses (Octopus bimaculoides). The babies, which were collected in Santa Barbara and hatched at Hopkins, are much easier to handle, and are also extremely cute!
We are writing this blog to share our research and findings about octopus intelligence and eye function. Many of you may have heard stories of cephalopods recognizing their caretakers or solving various puzzles, and we are eager to learn more about these fascinating creatures. We want to understand how octopuses learn and perceive their worlds, and how they use their intelligence to overcome obstacles. What makes these mysterious creatures so advanced and easy to relate to, when they are so different from ourselves?
To start our project, we took a trip to Hopkins Marine Station in Pacific Grove, CA on March 23, 2010. We were lucky enough to have been introduced to Judit Pungor, a cephalopod researcher and enthusiast. She showed us around the station and the octopus lab she works in, told us about her current work, and familiarized us with the lab's interesting creatures. We discussed the intent of our project, and Judit helped us narrow our focus so we could research more efficiently. Before we left, Judit offered to take the adult Red Octopus (Octopus rubescens) out to introduce it to us, but the moment she took the heavy weight off its tank, the sneaky little guy tried to push the lid off the tank and leap out, splashing water all over the place in the process.
We learned a lot during just our first visit, such as the possibility that octopuses may be able to see polarized light. This inspired us to consider various experiments we could perform to test the presence and usefulness of such an ability. We plan to go visit Hopkins soon so we can conduct our own experiments, and get to know the octopuses a little better!
The tupperware container where the baby Two-Spots are kept, with shells and other knick knacks.
Close up of our test subject under orange light.
The little Two-Spot hiding in a corner during exposure to blue light.
View of the school's small private beach, with a cool view of the aquarium in the background
Some cormorants on a rock
One of the buildings at Hopkins.
An awesome giant squid sculpture on the ceiling of Judit's lab!
Our workspace.
Our supplies.
Some geese we ran into as we were leaving!
