OCTOPUS -THE EIGHT LIMB CREATURE

The octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. Around 300 species are recognized, and the order is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, the octopus is bilaterally symmetric with two eyes and a beak, with its mouth at the center point of the eight limbs (traditionally called "arms", sometimes mistakenly called "tentacles"). The soft body can rapidly alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates. 

 Most octopuses stay along the ocean’s floor, although some species are pelagic, which means they live near the water’s surface. Other octopus species live in deep, dark waters, rising from below at dawn and dusk to search for food. Crabs, shrimps, and lobsters rank among their favorite foods, though some can attack larger prey, like sharks. Octopuses typically drop down on their prey from above and, using powerful suctions that line their arms, pull the animal into their mouth. The octopus performs its famous backward swim by blasting water through a muscular tube on the body called a siphon. Octopuses also crawl along the ocean’s floor, tucking their arms into small openings to search for food. Seals, whales, and large fish prey on octopuses.

If threatened, octopuses shoot an inky fluid that darkens the water, confusing the aggressor. The octopus can also change to gray, brown, pink, blue, or green to blend in with its surroundings. Octopuses may also change color as a way to communicate with other octopuses. Octopuses are solitary creatures that live alone in dens built from rocks, which the octopus moves into place using its powerful arms. Octopuses sometimes even fashion a rock “door” for their den that pulls closed when the octopus is safely inside.

Octopuses have three hearts: one pumps blood around the body; the other two pump blood to the gills. The reason for this impressive cardiac hardware ... probably comes down to the unusual composition of their blood.

Interesting Octopus Facts:
All octopuses have head, called mantle, surrounded with 8 arms, called tentacles. All vital organs are located in their head.
Their color and size is determined by their environment. Those that live in colder water will be much larger than those that live in tropical (warm) water.
Only hard structure in their body is beak which looks like a parrot beak. They use their beaks for eating.
Using strong suction cups (240 on each tentacle), they hunt crabs, mollusks and crayfish.
They have 3 hearts and their blood is blue in color.
Although they are invertebrates, they have incredibly developed nervous system and they can learn various things. Some experiments showed that they can solve puzzles, distinguish shapes and patterns. They can develop both short- and long-term memory.
Because of the highly developed nervous system, some people believe that octopuses feel the pain during operation and demand the use of anesthesia before surgery.    They can change their color and texture of the skin to blend with environment and become invisible. They will eject dark ink that will confuse the predators and give them a chance to escape. If predator grabs them for any tentacle, they will reject it. Soon after, new tentacle will grow. Some octopuses produce very potent toxin that can stun the prey or hurt a man. Most dangerous octopus is blue-ringed octopus that can kill few people at once.  OCTOPUS Male octopus will die few months after mating. Female will survive until her eggs hatch. She will die of starvation, because she will not eat three months (time needed for eggs to hatch).  Female lay up to 150 000 eggs in a week. After hatching, small octopuses will float short period of time with plankton and then swim back to the bottom of the sea. Octopuses live from few months to few years, depending on the species.