What’s the Difference Between Octopus and Squid?

Difference between Octopus and Squid

What’s the difference between octopus and squid? Because of their superficial similarities, the two cephalopods are frequently mixed up.

In the end, they both have eight limbs, high cognitive levels, and the ability to release ink from their ink sacs and conceal their bodies to escape being eaten by their target.

Nevertheless, despite these similarities, octopus and squid are distinct in many essential ways. If you want to test your skepticism, all you have to do is go to a restaurant and order a platter of calamari or octopus tentacles.

In a short amount of time, you will see that these ancient marine-dwelling species each have distinctive characteristics that set them apart from the others in the group. This article will focus on eight important differences between octopus and squid.

1. Size

Overall, there isn’t much of a size difference between octopus and squid. However, there is considerable variation in squid species near the extremes. Octopus wolfi is the tiniest octopus, measuring just under 1 inch in length and weighing around a gram.

Meanwhile, the enormous Pacific octopus can grow to be 30 feet long and weigh about 600 pounds. While these measurements are extraordinary, the contrast becomes clear when compared to the tiniest and largest squids.

The Thai bobtail squid, for example, is the smallest known mollusk. It’s smaller than a half-inch long and weighs less than a gram.

On the other hand, the enormous squid can grow to be over 43 feet long and weigh more than a ton. In essence, whereas octopuses grow larger on average than squids, squids have a wider size range.

2. Head and Mantle

Octopuses and squids are both head-footed creatures with their vital organs wrapped in a mantle. However, their mantle and head appear significantly different when compared side by side.

Octopuses have a spherical mantle and a bulbous appearance. Their mantles come in a variety of colors and patterns, but many species use camouflage to blend in with their surroundings. Except for the deep-diving Dumbo octopus, octopuses do not have mantle fins.

Squid mantles, on the other hand, are triangular. Fins, unlike octopuses, have tiny fins on each side of their mantle that they employ for mobility and navigation.

Squid patterns and colors appear more muted, but they can also disguise themselves when attacked.

3. Habitat

Another striking difference between octopus and squid is their habitats; the preferred habitat of octopus and squid differs in various ways.

Octopuses, in general, live near the seafloor. They make their dens in coral reefs, near shorelines, and on the ocean floor, at both deep and shallow depths.

However, a few species of octopus spend most of their life in the open ocean, but they are the exception rather than the rule. Squids, on the other hand, are primarily found in the open ocean.

They don’t need to live near the ocean floor because they don’t form dens like octopuses. They are common both near the surface and at abysmal depths.

4. Arms

Another difference between octopus and squid in their arms. While they appear similar at first glance, closer inspection reveals many distinctions. The limbs of octopuses typically have one to two rows of suckers.

They do not, however, develop sucker rings or hooks on the ends of their arms. When migrating across the bottom, they utilize their arms to capture and hold prey and as a primitive type of mobility.
Meanwhile, squids’ arms may have sucker rings or suckers.

Furthermore, some species’ arms end in little hooks, which likely evolved to help the squid retain squirming prey.

The main distinction between the two is that squids also have two lengthy tentacles. Squids use their tentacles to catch prey and eight arms to hold their meal during feeding.

5. Diet and Feeding

Octopuses, as previously said, use their arms to catch and hold prey, whereas squids use their tentacles to grab prey and their arms to grasp prey.

However, there is another difference between octopus and squid diets and feeding habits. Octopuses generally eat crustaceans like crabs, clams, and whelks, though some larger species will also eat fish and shrimp.

When they catch prey, they frequently drag it back to their den. They will use their strong beaks to inject deadly saliva into their food. The octopuses’ saliva paralyzes its victim and dissolves any hard outer shells, allowing them to eat on the delicate inside flesh.

Squids, on the other hand, eat shrimp and small fish. Rather than using their saliva to dissolve their prey, they tear through it and take chunks out with their formidable beaks.

6. Lifespan

The lifespan of an octopus and squid can vary greatly depending on the species. Most octopuses and squids die shortly after mating, which means their lives only last till they achieve sexual maturity and have the opportunity to mate.

On the other hand, squids appear to live longer in the wild. An octopus has a life expectancy of 1 to 3 years. Some octopuses, however, only live for six months, while others can live for up to 5 years.

Meanwhile, most squids live for one to five years. Although some only live for nine months, several squid species have been reported to live for nearly 15 years.

7. Socialization

For many years, scientists did not regard octopuses and squids as particularly friendly creatures. This makes it logical, given that they are usually solitary except during mating season.

Recent data, however, reveals that these early assumptions only told part of the tale. Most octopuses indeed prefer to live alone. Some species, however, will live in places with a high density of other octopuses.

Furthermore, certain species will share their den with other creatures, while others will hunt with fish cooperatively. Squids, however, appear to be far more gregarious than previously thought.

While some squids prefer to live alone, others, such as the bigfin reef squid, prefer to live in groups. Furthermore, research suggests that other squids may be able to communicate with one another. According to studies, Humboldt squids use color and lighting changes to communicate with one another.

8. Reproduction

There is no contest between octopus and squid regarding which animal is the best parent. Octopuses reproduce using a hectocotylus, a unique arm employed by males that deliver the male’s sperm into the female’s mantle cavity to fertilize the eggs.

Females will then lay their eggs inside their dens and ferociously guard their eggs until their children are born. Some females will even construct fences to keep possible predators out.

Squids, on the other hand, mate in huge numbers using a hectocotylus or a mechanism known as “head-to-head” mating.

Females tie their eggs to rocks or seaweed rather than guarding them. Some species don’t bother attaching their eggs to a solid surface, instead leaving them to drift in the open ocean until they hatch.


Even though the octopus and squid vary in several ways, these two creatures happen to share similar defense mechanisms against predators. To defend themselves against predators, squids and octopuses developed unique defense mechanisms.

When threatened, they can fire ink from their ink sac to distract their assailants. On the other hand, many species can camouflage their bodies to blend in with their surroundings, allowing them to evade potential attacks.

Interesting Facts About Octopuses and Squids

  • The giant squid can reach up to 58 feet (17.5 meters) in length. We are aware of this since they are occasionally washed up on a beach.
  • In the part of the water known as the “twilight zone,” you can find octopuses and squid. This is the region between approximately 200 and 1,000 meters (600 and 3,000 feet) below the surface, where only a small amount of light can penetrate.
  • Octopuses and squid employ jet propulsion to navigate their environments. This is somewhat analogous to the operation of a jet aircraft. They propel themselves forward by squirting water in front of them.
  • Both octopuses and squid have eight legs, but squid also has two tentacles on their bodies. The legs have suckers that run the entire length, and these suckers can be used to touch and taste.
  • Ink serves as a defense mechanism for cephalopods such as squid and octopuses. When they sense that they are in danger, they will expel a cloud of blue or black ink into the water, which will camouflage them while they escape the danger.
  • The bite of the blue-ringed octopus does not cause any pain, but it can be fatal to humans in a matter of minutes.
  • With the help of specialized organs located at the tips of its legs, the vampire squid emits a glow in the dark. It has been seen living as deep as 5,000 feet (or 1,500 meters) below the surface.
  • The blood of the octopus and squid are both blue.
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