Animal stories: Octopuses
Octopuses are the eight-armed animals with unique appearance and characteristics. They can change colour, squirt ink and re-grow lost body parts. The word octopus means ‘eight feet’. There are over 100 different species of octopuses. The Giant Octopus is the biggest octopus measuring up to 23ft long from arm tip to arm tip and weighing up to 182 kg. The smallest is the Californian octopus that is only 1 cm long. Octopuses have very soft bodies that even a fully-grown adult can squeeze through a hole that is as big as a large coin. They have eight distinctive arms with two rows of suction cups, massive bulbous head and large eyes. If they lose an arm, another arm will eventually grow again. Octopuses have excellent sense of touch and very keen eyesight. But octopuses cannot hear. They have blue blood and have three hearts.
Two pump blood through each of the two gills, while the third pumps blood through the body. Octopuses are considered intelligent because of the varieties of technique they use to protect themselves from their predators.
Octopuses live on the ocean floor. The common octopuses are found in the tropical and temperate waters of the world’s oceans. They are mostly found in dens, spaces under rocks, and crevices on the sea floor. They also dig holes under large rocks. They pile rocks to block the front of their den. The den protects them from predators and provides a place to lay eggs and care for them.
Octopuses mainly feed on small crabs, snails, fish, turtles and other octopuses. They catch prey with their arms, and then kill it by biting it with their tough beak, paralysing the prey with a nerve poison, and softening the flesh. They then suck out the flesh. Octopuses hunt mostly at night. They prey on crabs, crayfish and molluscs and will sometimes use their ink to disorient their victims before attacking.
Baby octopuses emerge from their eggs smaller than a pea. Around the time the eggs hatch, the mother dies and the young larval octopuses have to survive by their wits and powers. They feed on copepods, larval crabs and larval starfish until they are ready to sink down to the bottom of the ocean. So the young octopuses never get to know their parents. Some head off to explore the world, drifting in ocean currents.
Octopuses are experts in camouflage as they can change colour to blend in with their surroundings. They completely change their appearance and can match the colour, texture and patterns of the surrounding objects. No animal on Earth is better than octopuses at changing appearance. In a flash, they can change colour, make themselves smooth or sprout spikes.
Some octopuses put all the right bits together and take on the forms and colours of different species of fish. So their predators such as sharks, eels and
dolphins swim by without even noticing them. Octopuses usually release a cloud of black ink when they are in danger.
They do it to obscure their predator’s view. The ink also contains a chemical that weakens the predator’s sense of smell. So that it becomes difficult to track the fleeing octopus.
Some people keep octopuses, as pets but it can be difficult to keep them in captivity because of their intelligence. They have problem solving skills,
mobility and lack rigid structure. And they are known to escape opening the covers of their aquariums.