Octopus : Animals with 3 hearts and 9 brains

After hearing "an animal with multiple limbs", most of the time the first creature which comes in our minds are octopuses. We are going to learn about this creature as deeply as possible, but also being simple and accurate at the same time.  As you already read the title, we are going to find out why an octopus requires 3 hearts and 9 brains for the functioning of it's body, or do they need all of them ?. Also, aside from hearts and brains, we will learn about all the other major information and facts about this animal. Let's go.

Octopoda (Octopus)

General Info

Octopuses are medium/big sized aquatic animals which are found in all the oceans around the world. Their are around 300 discovered species of octopuses and none of them live in fresh water. They are considered to be quite smart in the animal kingdom and are also the smartest among all the invertebrates.  Although they prefer to move and crawl slowly on the bottom surface of the ocean, they can be very quick and agile in terms of motion and reaction time. Most species of octopuses can be easily identified by their big head, and locomotive motion. Different species have different features and characteristics.

These creatures came into existence around 296 million years ago. The total population of octopuses to the date is unknown. Also they have relatively short lifespans of 6 months to 5 years, depending on the specie with the average lifespan of 3 to 5 years.

Physical Characteristics

Octopuses are generally medium size but are also found in small or very tiny and giant sizes. In terms of body appearance, they are generally brown, black, red, yellow or orange in colors but some can also be found in with multiple colors on their body. Also, some species of octopuses have the ability to change their body color by changing skin pigments according to the surroundings.  

As for their size, they can be anywhere between 0.025 to 6 meters (0.082 to 20 feet) in length and less than a gram to 22 to 30 pounds (9.9 to 13 Kg) in weight. Although the largest specimens recorder were way to much bigger and heavier than the average ones, like the most largest specimen ever recorded was nearly 30 feet (9.144 meters) in length and around 600 pounds (272.155 Kg) in weight.

They have flexible limbs and tentacles through which they crawl (or crawl) on the bed surface of oceans. They normally use the two limbs at the back to walk on the ocean floor and the remaining 6 limbs are use to grip the side by objects or for more faster movement. They use jet propulsion for faster movement in which they intake water through their body cavity and release this water through a funnel or tube like part of their body, thus creating an outer thrust to move the body. Their bodies are extremely flexible and can sweep through tight gaps and areas without any problem.

They have small beak like mouth which they use the cut or break the shells and body of their prey. This beak is surrounded by the limbs under their head which can not be seen unless the limbs are out of the way and the head is tilted to an angle, which is obvious. Also, all octopuses are venomous and are enough to kill a adult human in no time.

Behavior and lifestyle

Octopuses are generally shy creatures. They do not want themselves to get involved in any kind of trouble for no reason because as mentioned before, they are smart and don't do stupid things before thinking. Most of the species of octopuses recorded were found out to be not aggressive to humans at all. Whenever they feel like that they are in danger, they immediately secrete ink like substance as smoke screen and try to escape quickly.

These animals prefer to live alone rather than in groups.They are only seen in groups during the mating season. They wander over the sea floor, live in rock dens or sometimes live in shells or other areas. Most of them live in deep water ranging from 3300 to 22,824 feet (1000 to 6957 meters) deep inside the oceans. However, some species like the the large pacific stripped octopuses live in groups of 35 to 40 individuals.

They are free swimmers and don't tend to posses their own specific are or territory but mostly stay in the area they most know about. They usually don't go far from their current preferred location unless they have to find food. They can find a specific known are which they have visited before without any trails or other navigation hints. Also, they do not show any signs of migration any often live in a same area for a long time.

As for their diet, they mainly eat small and medium sized fishes, lobsters, shrimps and crabs. But they can also eat other small sharks, birds and even their own kind. Yep, octopuses show cannibalism. Their common enemies are Sharks, dolphins, eels (like Moray and Conger eels) and seals.

Biological features

Nervous and Circulatory system

Octopuses have a very complex nervous system. Around 67% of their nerve cells are located in the nerve cords of their limbs. The 9 donut shaped brains (which act as one) wrapped around the food pipe are located inside their head and are connected to to special organs called statocysts which helps them to analyse their body movement and sense their acceleration and force of gravity during movement.

Their blood is highly viscous in nature and requires great pressure to flow the blood through out the whole body therefore, they have 3 hearts (also located in the head). Two hearts are used to flow blood to the gills and the other heart is used to pump blood in the rest of the body. The parallel plate like structure of the gills allow them to intake around 65% of oxygen under water which is quite high. Even at rest, their skin absorbs around 41% oxygen.

Camouflage and mimicry

They skin pigments on fair number of octopus species can be activated to change color and appearance and skin texture to provide them with almost perfect camouflage. These skin pigments are called chromatophores. Also some species of them have the ability to transform their body and act like different creatures, for example, the Indonesian mimic octopus can transforms it's body to look like a coral snake or a small ray. 

Ink or smoke screen

Near the digestive gland, there is an ink secreting sac which is black in color due to melanin cells. A funnel type structure is present near the below the head and near the mouth from which the ink is pumped out which is covered with mucus and thick viscous substances which when thrown, creates a thick blurry cloud of smoke screen, providing them enough time to escape from a predator.

Micro-organisms

Octopuses are found to have a number of different micro-organisms like pathogens, eukaryotic animals (around 150 of them) and parasites on their body. Due to this, they consists of some serious diseases and often die from these. However most of the normal microbes are taken care of with the haemocytes cells which also helps them to heal the body.

RNA editing 

Octopuses are capable of high RNA editing than any other animal. In simple word, they are capable of making different and dissimilar changes in the RNA molecules of their body.\

Reproduction

The mating seasons of octopuses is not specific. At the age of 10 months or 1 year, both male and female octopuses become sexually mature. males undergo some physical changes and develops a "third arm" (or we can say the 9th limb) which is used while mating and intercourse.

After the mating, the male dies of biological aging as the male uses all the energy and nutrients in the body during the mating. However the female lives, but only for the eggs to be hatched. After the gestation period of about 1590 days (~53 months/ 4.5 years), the female also dies because of the lack of nutrients in the body as she was protecting the eggs this whole time. 

A female octopus can lay anywhere between 10,000 to 70,000 eggs. The eggs take 5 to 10 months to hatch, depending upon the species and conditions (like depth and pressure). After the eggs are hatched, the baby octopuses feed themselves on Planktons and other small organism on the upper surface for around 45 to 60 days and after that they come back to the ocean's floor.

Facts and summary

• Octopuses are found in different sizes, all from tiny to medium or to a giant size.

• Their are 300 species of octopuses recorded to this date.

• They have short life spans (6 months to 5 years max).

• They have 3 hearts and 9 brains.

• They are very intelligent (equivalent of a house cat).

• They are venomous and are capable enough to kill an adult human being, although they are not aggressive in nature.

• They have a very complex nervous system.

• They release ink as a smoke screen in order to escape from their predators.

• The male octopus die after mating with the female, and the female also dies after the eggs are hatched because of the same reasons which is low body energy, starvation and biological aging.

• Their bodies are very flexible.

• Their blood is blue in color and are also cold blooded.

• They also have good eyesight but a bad hearing sense (almost deaf).

• They also have a good sense of touch.

• They are also recorded while eating their limbs because of being bored or in depression and stressed (yes they do get stressed out!).

• They are very good in camouflage and body transformation.

• Not all the octopuses have 8 limbs.

• The most dangerous one till now is the Blue ringed octopus.

• Their arms have brains of their own.

• Their limbs are called "arms" not "tentacles".

• They have the ability to re-grow their arms.

• Octopus uses jet propulsion to swim.

• The head of the octopus is called "mantle" which contains all the vital organs of their body.

🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙🐙