Friday, 24 April 2009
Monday, 6 April 2009
As pets
Though octopuses can be difficult to keep in captivity, some people keep them as pets. Octopuses often escape even from supposedly secure tanks, due to their problem solving skills, mobility and lack of rigid structure.
The variation in size and life span among octopus species makes it difficult to know how long a new specimen can naturally be expected to live. That is, a small octopus may be just born or may be an adult, depending on the species. By selecting a well-known species, such as the California Two-spot Octopus, one can choose a small octopus (around the size of a tennis ball) and be confident that it is young with a full life ahead of it.
Octopuses are also quite strong for their size. Octopuses kept as pets have been known to open the covers of their aquariums and survive for a time in the air in order to get to a nearby feeder tank and gorge themselves on the fish there. They have also been known to catch and kill some species of sharks.
The variation in size and life span among octopus species makes it difficult to know how long a new specimen can naturally be expected to live. That is, a small octopus may be just born or may be an adult, depending on the species. By selecting a well-known species, such as the California Two-spot Octopus, one can choose a small octopus (around the size of a tennis ball) and be confident that it is young with a full life ahead of it.
Octopuses are also quite strong for their size. Octopuses kept as pets have been known to open the covers of their aquariums and survive for a time in the air in order to get to a nearby feeder tank and gorge themselves on the fish there. They have also been known to catch and kill some species of sharks.
Saturday, 4 April 2009
Octopuses have keen eyesight. Although their slit-shaped pupils might be expected to afflict them with astigmatism, it appears that this is not a problem in the light levels in which an octopus typically hunts.[citation needed] They do not appear to have color vision, although they can distinguish the polarization of light. Attached to the brain are two special organs, called statocysts, that allow the octopus to sense the orientation of its body relative to horizontal. An autonomic response keeps the octopus' eyes oriented so that the pupil slit is always horizontal.
Octopuses also have an excellent sense of touch. An octopus' suction cups are equipped with chemoreceptors so that the octopus can taste what it is touching. The arms contain tension sensors so that the octopus knows whether its arms are stretched out. However, the octopus has a very poor proprioceptive sense. The tension receptors are not sufficient for the octopus brain to determine the position of the octopus' body or arms. (It is not clear that the octopus brain would be capable of processing the large amount of information that this would require; the flexibility of an octopus' arms is much greater than that of the limbs of vertebrates, which devote large areas of cerebral cortex to the processing of proprioceptive inputs.) As a result, the octopus does not possess stereognosis; that is, it does not form a mental image of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture.[16]
The neurological autonomy of the arms means that the octopus has great difficulty learning about the detailed effects of its motions. The brain may issue a high-level command to the arms, but the nerve cords in the arms execute the details. There is no neurological path for the brain to receive feedback about just how its command was executed by the arms; the only way it knows just what motions were made is by observing the arms visually.[16]
Octopuses also have an excellent sense of touch. An octopus' suction cups are equipped with chemoreceptors so that the octopus can taste what it is touching. The arms contain tension sensors so that the octopus knows whether its arms are stretched out. However, the octopus has a very poor proprioceptive sense. The tension receptors are not sufficient for the octopus brain to determine the position of the octopus' body or arms. (It is not clear that the octopus brain would be capable of processing the large amount of information that this would require; the flexibility of an octopus' arms is much greater than that of the limbs of vertebrates, which devote large areas of cerebral cortex to the processing of proprioceptive inputs.) As a result, the octopus does not possess stereognosis; that is, it does not form a mental image of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture.[16]
The neurological autonomy of the arms means that the octopus has great difficulty learning about the detailed effects of its motions. The brain may issue a high-level command to the arms, but the nerve cords in the arms execute the details. There is no neurological path for the brain to receive feedback about just how its command was executed by the arms; the only way it knows just what motions were made is by observing the arms visually.[16]
Octopuses are highly intelligent, likely more so than any other order of invertebrates. The exact extent of their intelligence and learning capability is much debated among biologists,[4][5][6][7] but maze and problem-solving experiments have shown that they do have both short- and long-term memory. Their short lifespans limit the amount they can ultimately learn. There has been much speculation to the effect that almost all octopus behaviors are independently learned rather than instinct-based, although this remains largely unproven. They learn almost no behaviors from their parents, with whom young octopuses have very little contact.
An octopus opening a container with a screw capAn octopus has a highly complex nervous system, only part of which is localized in its brain. Two-thirds of an octopus' neurons are found in the nerve cords of its arms, which have a remarkable amount of autonomy. Octopus arms show a wide variety of complex reflex actions arising on at least three different levels of the nervous system. Some octopuses, such as the Mimic Octopus, will move their arms in ways that emulate the movements of other sea creatures.
In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practice observational learning,[8] although the validity of these findings is widely contested on a number of grounds.[4][5] Octopuses have also been observed in what some have described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them.[9] Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing boats and opened holds to eat crabs.[6]
In some countries, octopuses are on the list of experimental animals on which surgery may not be performed without anesthesia. In the UK, cephalopods such as octopuses are regarded as honorary vertebrates under the Animals (Scientific Procedures) Act 1986 and other cruelty to animals legislation, extending to them protections not normally afforded to invertebrates.[10]
An octopus opening a container with a screw capAn octopus has a highly complex nervous system, only part of which is localized in its brain. Two-thirds of an octopus' neurons are found in the nerve cords of its arms, which have a remarkable amount of autonomy. Octopus arms show a wide variety of complex reflex actions arising on at least three different levels of the nervous system. Some octopuses, such as the Mimic Octopus, will move their arms in ways that emulate the movements of other sea creatures.
In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practice observational learning,[8] although the validity of these findings is widely contested on a number of grounds.[4][5] Octopuses have also been observed in what some have described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them.[9] Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing boats and opened holds to eat crabs.[6]
In some countries, octopuses are on the list of experimental animals on which surgery may not be performed without anesthesia. In the UK, cephalopods such as octopuses are regarded as honorary vertebrates under the Animals (Scientific Procedures) Act 1986 and other cruelty to animals legislation, extending to them protections not normally afforded to invertebrates.[10]
Tuesday, 31 March 2009
octopus story and half shark story
one bright morning in a beautiful ocean there lived an octopus the octopus was near an shark and the octopus was changed couler so the shark couldn't see the octopus then the shark left. Then really slowly and really quiet and the octopus swam up and gabbed the shark then all that was left was the octopus because the shark was eaten by the octopus SUDDENLY THERE WAS A NET!!!!!!!!!!!!!!!!!!!!!!!!!!!THEN THE NET GRABBED THE OCTOPUS AND SWAM UP WITH THE OCTOPUS. Then there was no octopus left in the ocean because that was the last octopus in the ocean and there was 1 shark in the ocean then next morning the octopus was swimming around and looking for fish and he found some fishes and when the fishes were not looking the shark eat them as fast as it could . Next the fishes thought that whenever they see the shark they will hide in a good spot that were the shark would not find them and the next day 10 of the fishes saw the shark and they did what they thought and they found a very good hiding spot and then the shark couldn't see them and left.Then there was ANOTHER NET!!!and all the fishes hoped that the shark would get catched and there dream came true the shark did get caught!. Then the ocean was nothing but fishes and all other stuff that aren't bad and now they can do anything and olso the best part was they wont get eaten. the end
The octopus (pronounced /ˈɒktəpəs/, from Greek ὀκτάπους (oktapous), "eight-footed",[1][2] with plural forms: octopuses [ˈɒktəpʊsɪz], octopi [ˈɒktəpaɪ], or octopodes [ˌɒkˈtəʊpədiːz], see below) is a cephalopod of the order Octopoda that inhabits many diverse regions of the ocean, especially coral reefs. The term may also refer to only those creatures in the genus Octopus. In the larger sense, there are around 300 recognized octopus species, which is over one-third of the total number of known cephalopod species.
An octopus has eight flexible arms, which trail behind it as it swims. Most octopuses have no internal or external skeleton, allowing them to squeeze through tight places. An octopus has a hard beak, with its mouth at the center point of the arms. Octopuses are highly intelligent, probably the most intelligent invertebrates. They are known to build "forts" and "traps" in the wild, and for rearranging tanks and burying other animals alive in domestication[citation needed]. For this reason, they are quite notorious among aquarium operators.[3] For defense against predators, they hide, flee quickly, expel ink, or use color-changing camouflage. Octopuses are bilaterally symmetrical, like other cephalopods, with two eyes and four pairs of arms.
An octopus has eight flexible arms, which trail behind it as it swims. Most octopuses have no internal or external skeleton, allowing them to squeeze through tight places. An octopus has a hard beak, with its mouth at the center point of the arms. Octopuses are highly intelligent, probably the most intelligent invertebrates. They are known to build "forts" and "traps" in the wild, and for rearranging tanks and burying other animals alive in domestication[citation needed]. For this reason, they are quite notorious among aquarium operators.[3] For defense against predators, they hide, flee quickly, expel ink, or use color-changing camouflage. Octopuses are bilaterally symmetrical, like other cephalopods, with two eyes and four pairs of arms.
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