Octopuses: Weird sea-creatures

When it comes to weird sea-creatures, octopuses are hard to beat. There’s the well-known ink-squirting defence system, the bird-like beak, and the eight tentacles with their double rows of suckers.

Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms. Octopuses have no internal or external skeleton, allowing them to squeeze through tight places. Octopuses are among the most intelligent and behaviorally flexible of all invertebrates.

Octopuses live in all oceans. This salt water creature tends to be small in warm tropical waters and larger in colder waters. Largest one ever caught was 600 pounds, the tentacles spanning 33 feet! But usually they range from 50 to 90 pounds. Most only live to be 1 or 2 years old but some big ones live to be 4.

Each tentacle of an octopus contains a double row of 120 suckers each ranging in size from a pinhead to 2 ½ inches in diameter. With them he can not only grab his prey, but also taste it. The combined grip of these 8 arms exceeds 2000 pounds!

The octopus has no bones. The only hard part is the beak. Because of this, a 60 pound octopus can actually work its way through a 2 inch hole to escape.

Octopuses have three hearts. Two branchial hearts pump blood through each of the two gills, while the third pumps blood through the body. Octopus blood contains the copper-rich protein hemocyanin for transporting oxygen. Although less efficient under normal conditions than the iron-rich hemoglobin of vertebrates, in cold conditions with low oxygen pressure, hemocyanin oxygen transportation is more efficient than hemoglobin oxygen transportation.

The octopus produces a poison in its saliva. It is spit this into a wound inflicted by the beak. This is lethal to crabs, lobsters, and eels but only burns the skin of people. Lunch is then passed by the tentacles to the mouth to be ingested.

They have numerous strategies for defending themselves against predators, including the expulsion of ink, the use of camouflage and deimatic displays, their ability to jet quickly through the water, and their ability to hide. An octopus trails its eight arms behind it as it swims. All octopuses are venomous, but only one group, the blue-ringed octopuses, is known to be deadly to humans.

Octopuses are highly intelligent, likely more so than any other order of invertebrates. The maze and problem-solving experiments have shown that they show evidence of a memory system that can store both short- and long-term memory.