The life cycle of an octopus has four stages- egg, larva, juvenile, and adult. It is a unique under-sea life cycle where the male dies within a few months of mating and the female dies soon after hatching of the eggs.

An octopus is a soft-bodied, eight-armed marine creature which falls under Class Cephalopoda under Order Octopoda. The size of octopus varies spending on its genus. The size of the smallest octopus is around 5 cm in length while the size of the largest octopus is around 6 meters in length. The main features of octopus include a pouch-like huge head, which is slightly separated from the body, compound eyes and eight arms. A tissue, known as the skirt attaches the arms and each arm is made up of two rows of powerful fleshy suckers.

Octopus: An interesting Undersea Creature

Reproduction, or for that matter, mating is quite a serious business for octopi the very first reason being only one per cent of around 200,000 eggs an adult octopus lay gets to survive and reach adulthood. Depending on the species, an octopus generally lives up to three to five years. They grow rapidly. Study shows, a young octopus can grow by five per cent every day, thanks to their amazing metabolic rate. Upon reaching maturity they start to reproduce.

Each pair of male and female octopus produces only one batch of young and then dies. It’s like reproduction is the only purpose of their life. The male octopus, as stated earlier, dies usually after a few months of mating, while the female just lives to see the eggs hatching (which usually takes ten months); and after nurturing the eggs, it dies.

Systematic Position of Octopus

Kingdom: Animalia

Phylum: Mollusca

Class: Cephalopoda

Order: Octopoda

Family: Octopodidae

Subfamily: Octopodinae

Genus: Octopus

The Life Cycle Of Octopi

The life cycle of octopus is divided into four stages namely, the Egg (stage 1), the Larva (stage 2), the Juvenile (stage 3) and the Adult (stage 4). The four stages of the life cycle of octopus are discussed vividly in the following paragraphs:

1. The Egg (Stage 1):

Octopi lay eggs after fertilization. The size of the eggs measures up to 0.3 cm in length. A common form of octopus such as O. Vulgaris has the ability to lay more than 10,000 eggs and the eggs are laid in small holes and under rocks. The eggs are cleaned on a regular basis with the help of the suckers until the hatching of the eggs. Female octopus saves the eggs with her life during this stage.

2. The Larva (Stage 2):

The hatching of eggs is done by the larval octopus after four to eight weeks of the development. The newborn larval octopi are all on their way. The newly emerged larval octopi are called octopods. They look like adult octopi and stay at the surface of the ocean. At the initial stage, octopods drift in the plankton for a long span of time before entering into the bottom of the ocean. At this stage, octopods are fed by larval crabs, larval starfish and larval lobsters. Octopods stay on plankton for a long period of time and they are fed on it in frequent manner. These larvae swim down to the bottom of the ocean after a certain point of time.

3. The Juvenile (Stage 3):

The juvenile octopi begin to develop at a rapid pace during this stage. The weight of juvenile octopus is increased by 5 per cent every day because of its constant feeding habits. At the last stage of the life cycle of the octopus, the weight of the octopus is one-third as much as the food it has taken. The larval octopus may enter the adult stage of its life if the circumstances are suitable. This happens because of the small life expectancy of the octopus.

4. The Adult (Stage 4):

Octopi are sexually mature and ready to mate when the octopi enter into this stage. A modified arm known as hectocotylus is used by the male octopus to release sperms into the mantle cavity of the female octopus. The male octopi die after a few months of mating. After hatching of the eggs the female octopus also dies. Sperms can be stored for several weeks after mating by the certain species of octopi.

What Are The Characteristic Features Of An Octopus?

The octopus bears the following characteristics:

Octopi are categorized as predators and they attack their prey by dropping down on them and enclosing it with their arms. As a result, the prey is pulled into their beaks and broken up. The beak of the octopus is similar with the beak of the parrot.
Octopus is rich with a brilliant sense of touch, powerful beak-like jaws and venomous saliva. They are able taste what they are touching with the help of the receptors in the suckers.
A very significant characteristic of the octopus is its ability to squeeze itself into surprisingly small cracks and crevices. The soft body and dearth of internal skeleton are the reasons behind this.
There are three hearts in an octopus; two of them pumps blood to the gills and blood is circulated to the rest of the body by the third heart.
Octopus has blue coloured blood. The presence of haemocyanin makes the blood of the octopus blue.
Octopi can swim very fast. But generally, they prefer to crawl instead of swimming because the systemic heart becomes inactive and stops circulating blood to its organs at the time of swimming and thus they become very exhausted.
The life span of the octopus is very small. Some of the species of octopus survive only for six months. The life span of a giant octopus is about five to six years.
Most commonly, the octopi live at the bottom of the ocean. But sometimes they are also found on the surface of water drifting alongside planktons. They feed on large fishes, seals and whales.

The octopus is considered as a brainiac among the invertebrates. A number of researches have been conducted on the intelligence of this sea creature. However, a lot more remains there to be studied. Nevertheless, the life cycle of octopus has a huge significance as it provides an insight into the life of oceanic invertebrates.

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FAQs on Octopus Life Cycle: Complete Guide for Students

1. What are the main stages in the life cycle of an octopus?

The octopus life cycle is a fascinating process that consists of four main stages. It begins with the egg, which hatches into a larva, then develops into a juvenile, and finally matures into an adult. This cycle is unique because it is semelparous, meaning the octopus reproduces only once before dying.

Stage 1: Egg: The female octopus lays thousands of eggs in a safe den and guards them until they hatch, not eating during this entire period.
Stage 2: Larva (Planktonic Stage): After hatching, tiny octopuses drift in the ocean as plankton. They are vulnerable and feed on other small planktonic organisms.
Stage 3: Juvenile: Once they grow large enough, they sink to the ocean floor and begin to live and hunt like miniature adults. This stage involves rapid growth.
Stage 4: Adult: The octopus reaches full maturity, hunts larger prey, and eventually seeks a mate to reproduce, restarting the cycle.

2. Why do most octopuses die shortly after reproducing?

The short lifespan of an octopus after reproduction is a programmed biological process. The male octopus dies within a few months of mating. The female, after laying her eggs, dedicates herself to protecting them, forgoing food entirely. This period of starvation, combined with the immense energy spent on guarding the eggs, leads to her death soon after the eggs hatch. This reproductive strategy, known as semelparity, ensures all parental energy is invested into the survival of the offspring.

3. What makes the octopus one of the most intelligent invertebrates?

The octopus is considered highly intelligent due to its complex nervous system and large brain-to-body mass ratio, the largest of any invertebrate. Their intelligence is demonstrated through problem-solving abilities, tool use, and observational learning. A remarkable feature is that about two-thirds of an octopus's 500 million neurons are located in its arms, not its brain. This allows each arm to act semi-independently to touch, taste, and manipulate objects, contributing to its sophisticated behaviours.

4. How does an octopus use camouflage to survive?

An octopus is a master of camouflage, using it for both hunting and defence. It can change its appearance in a fraction of a second through a combination of three key mechanisms:

Colour Change: Specialised pigment-filled sacs in its skin called chromatophores can be rapidly expanded or contracted to change colour and create complex patterns.
Texture Change: It can alter its skin texture to be smooth or bumpy by controlling small muscle bundles called papillae, allowing it to mimic rocks, coral, or sand.
Posture Change: An octopus can change its body shape and posture to imitate other objects or animals, such as algae or a sea snake.

5. What is the natural habitat and diet of an octopus?

Octopuses are found in every ocean of the world, from shallow coastal waters and coral reefs to the deep ocean floor. Their specific habitat depends on the species. Their diet is varied, as they are carnivorous predators. Bottom-dwelling octopuses typically feed on crabs, clams, and worms, using their strong beaks to break through shells. Octopuses living in open waters often prey on prawns, fish, and other cephalopods.

6. Why can an octopus only survive for a few minutes out of water?

An octopus cannot survive for long out of water because it breathes using gills, which are specifically adapted to extract dissolved oxygen from water. When an octopus is removed from the water, its delicate gill structures collapse under their own weight without the buoyancy of water to support them. This collapse dramatically reduces the surface area available for oxygen absorption, leading to suffocation within minutes.

7. How does an octopus defend itself from predators if camouflage fails?

If camouflage is not enough, an octopus has several other defence mechanisms. Its most famous defence is its ability to shoot a thick, dark cloud of ink at an attacker. This ink cloud obscures the predator's view and can also contain substances that irritate its sense of smell, creating a distraction that allows the octopus to escape. Additionally, octopuses are very flexible and can squeeze into tiny cracks and crevices to hide from predators.

8. What is the typical lifespan of an octopus and how does it vary by species?

The lifespan of an octopus is generally short and varies significantly between species. Most octopuses live for about one to two years. Smaller species, such as the Blue-Ringed Octopus, may only live for 6 to 18 months. In contrast, larger species like the Giant Pacific Octopus can live longer, typically between 3 to 5 years under ideal conditions. This short lifespan is directly linked to their reproductive cycle, as they die soon after mating.