Octopus vs. Squid: What’s the Difference?

Octopuses and squids might have a lot of similarities, but they’re both incredibly unique creatures with their own lifestyles and some interesting characteristics.

Sep 14, 2023byCaitlin Ross
octopus squid difference

It’s easy to become entranced and captivated by the ocean’s gorgeous and mysterious creatures, but we sometimes forget that there’s often more to marine life than meets the eye. Two fascinating creatures of the deep are often lumped together due to their similarities – these are the octopus and the squid. Although they’re both cephalopods, these unique creatures are complete individuals with lots to learn about!


large octopus
Image credit: Scientific American

When it comes to body shape and structure, people often mistakenly confuse octopuses and squids thanks to their eight long, flowing arms, cleverly equipped with suction cups. However, eight arms alone aren’t enough to make these two creatures one and the same.

Neither of these agile animals has a skeleton, but where the octopus has a rounder body, the squid is more elongated, making it more streamlined and built for speed.

A squid also possesses two fins and a stiff structure (called a pen) that acts as a makeshift backbone. Another interesting thing to note is that while the octopus has eight arms, the squid actually has ten! Eight of them are arms like the octopus, and two of them are longer tentacles ending with hooks for capturing their prey.


tiny octopus
Image credit: Caters Clips

When it comes to size, octopuses exhibit crazy diversity. Some species are as small as only a few inches, fitting comfortably in the palm of your hand, while others can reach astonishing sizes. The biggest octopus in the world is the Giant Pacific Octopus, the largest of which was recorded to be 30 feet across and weighing over 600 pounds. There are other octopus species found in various parts of the world that are mind-blowingly large or heart-wrenchingly tiny.

Squids, on the other hand, are pretty average in size and typically fall around the 25-inch mark in length. Of course, there are giant squids out there that can reach up to 43 feet, but these are rare finds in the marine world. However, just because they’re smaller in size doesn’t make them any less awe-inspiring!


school of squid
Image credit: The Wire

The octopus is the lone wolf of the ocean world and lives in solitude for most of its life, preferring an independent lifestyle. These creatures exhibit incredible intelligence and possess some serious animal problem-solving skills that scientists have loved to explore and study. However, despite their big brains, they prefer to live alone in their elaborate dens, keeping themselves and their offspring safe from predators.

Squids, on the other hand, tend to be a little more sociable. Now, this doesn’t mean that they have a pack mentality or mate for life like penguins, but they have been known to group together in relatively large schools for mating or protection purposes.

This more social behavior of theirs allows them to relax in the safety-in-numbers concept, and their interesting communication patterns (including body movements and even bioluminescent displays) are a wonder to watch and learn about.

Defense Mechanisms

octopus ink
Image credit: Yahoo News UK

As we’ve already mentioned, the octopus is known for being a bit of a recluse, and it surely helps them stay safe from the bigger fish in the sea. These animals are masters of camouflage, changing their body color and texture to mimic their surroundings and avoid being noticed by predators.

They also avoid facing the unknown by staying safely packed away in their dens. However, when faced with a threat, they won’t hesitate to use their famous squirt of black ink to confuse their enemies and plan their escape.

When it comes to dealing with predators, squids have a different tactic: they’re fast. Their long, streamlined bodies allow them to move quickly and easily through the water, and this is assisted by their incredible jet propulsion tactics. Squids are able to expel water out of a muscular funnel with a great force that propels them backward for a quick and easy escape.

As a bonus point for squids, they can release ink, too, although they’re not as dense or potent as the octopuses display.


baby squid
Image credit: AZ Animals

The bland social life of the octopus is sadly reflected in their mating and reproductive capabilities. These creatures, both male and female, will perish shortly after reproducing.

Male octopuses possess a special arm known as the “hectocotylus,” which is used for reproduction, and after using it, they will typically die. Female octopuses lay hundreds of eggs and monitor them carefully, and then often waste away as well once the eggs have hatched.

Lucky for squids, they have a better setup. These guys also have specialized reproductive arms for egg fertilization. Female squids can lay hundreds to thousands of eggs, but unlike the octopus mom, she leaves them to their own devices without any parental care as soon as the eggs are laid.

Caitlin Ross
byCaitlin Ross

Caitlin is an animal lover at heart with a passion for writing and sharing this love with the world. She’s a born and raised South African and grew up always surrounded by animals: more pets than she can count, and regularly adventuring with her family into the bush, where she feels most at peace with the wildlife in their natural habitat.