While looking at the sea animals, octopus is one of the most fascinating creatures. This eight armed creature is considered to be the most intelligent in the sea life. Octopus has a bulgy head used to propel while it swims. Long arms of the octopus are located near its mouth and the only hard part of its body is the beak. Octopus is armed with suction cups on each of its arm. It has no shell, but the huge and highly developed eyes make it a dangerous predator. It usually preys the crabs, lobsters, sea turtles and other shellfish by seizing them in the sucker arms. There are some interesting facts about octopus:
The most appealing fact about the octopus is that it has a very complex nervous system, only a part of which is contained in its brain. Almost 75 % of an octopus's neurons are located in the nerve cords of its eight long arms, which have restricted functional liberty. An octopus arms show a variety of complex reflex actions which continue even if they have no input from its brain. Unlike vertebrate creatures, the complex motor skills of octopus are not controlled by the brain using an internal somatotopic map of its body. Some of them, like the mimic octopus make the arm movements that imitate the movements of other sea creatures.
Octopus sometimes constructs barricades of large stones whereas some of them hide in the rocky crevices at the approach of any suspected danger. They can even obscure the water by emitting dark ink from the ink sac they have as one of the inbuilt defense mechanisms. Octopus can also change color mostly from pinkish to the brown according to the mood and the environment.
Octopus reproduces sexually. During the mating process, one of the arms of the male octopus is transformed into a sexual organ which deposits the spermatophores in the mantle cavity of the female octopus. The eggs are enclosed in capsules and then are attached to a rock, where the female guards them till they hatch. The young octopus does not go through the larval stage.
Like other deep sea fish octopus is eaten in various parts of the world. Whereas the scientific classification is the phylum mollusca, class cephalopoda, order octopoda, family octopodidae, genus Octopus. There are various types of octopus found in different parts of the world.
There are about 300 types of octopuses. Most of 300 types of octopus are found in tropical or subtropical areas. Some of the types of octopus live in deep water and some of the types of octopuses live in shallow water. The most commonly known types of octopuses are the following:
Common Atlantic Octopus (Octopus vulgaris) :
The common Atlantic octopus can grow up to a size of 10 inches or 3 meters when measured together with its body and arms. They can change their body color with their surroundings. They can be found in different colors like pink, red, brown, grey and white with a green tinge. These are found in the coral reefs around Florida, West Indies and Mexico.
Giant Pacific Octopus (Octopus dofleini) :
This is the largest of the known Octopus species. It can grow up to a size of 23 feet. Their life is (4 to 5) years, which is slightly different from the normal octopus. They are found on the North Pacific Ocean continental shelf and across the Aleutians, and down to Japan. It weighs up to 600 pounds.
Pacific Red Octopus (Octopus reubescens) :
It has small white spots on the mantle and have web in front of their eyes. It can also change its color. The average life of this species is 2-3 years.
Blue Ringed Octopus :
This is the most poisonous of all cephalopods. There are around 10 different species of Blue Ringed octopus. Its body size is less than 5 cm and 10cm, and weighs less than 30 grams. It is of grey with patches of light brown. They feed on small crabs and shrimps. The life span of a Blue Ringed octopus is only (2-3) years, because both male and female die after copulation.
Day or Reef Octopus (Octopus cyanea) :
It is also known as Cyane's octopus or the Big blue octopus. They have a color changing. Their body can grow up to 16 cm and legs up to 80 cm. It feeds on crabs, shrimp, bivalves and small fishes. It is found throughout the Indo-Pacific region.
Two Spotted Octopus (Octopus Bimaculatus) :
It has a pear-shaped body and is found in variety of colors like grey, dark brown, red and all with black patches. They can grow up to 30 inches.
Reef Octopus (Octopus briarius) :
The Reef octopus is of blue green color and is clearly visible by the divers. They feed on crustaceans, bivalves and small fishes. They are found in the Bahamas and the Caribbean. They grow up to a size of 12 cm in length and their arms are around 60 cm. The females lay about 500 eggs, which hatch in 50-80 days and reach maturity in 150 days.
Caribbean Armstripe or Brownstripe Octopus (Octopus burry) :
It has distinctive brown stripe, which runs to the length of each arm, and so it is called as Carribean Armstripe. It is generally brown or grey. It buries itself in the sandy environment for self protection.
Atlantic Longarm Octopus (Octopus Defilippi) :
This species has long arms. Their arms are about 30 cm in length but the body is about 6 cm only. They grow up to 36 inches. They can change their color and feed mainly on variety of crabs. They are found in the coral reefs of Australia, Florida Keys and Malta.
Paul Allen, a German octopus, was considered to correctly predict results of football matches. This octopus lived from January 2008 to 26 October 2010 and was a popular attraction, at the Sea Life Centre in Oberhausen, Germany.