Squid Vs Octopus: What is the difference?

Appearances can be deceiving and while squids and octopuses may look similar to the untrained eye, they have plenty of unique characteristics that set them apart. Features such as multiple arms, big heads, and lack of backbone are key identifiers for both species, but their habitats, behavior, and lifespan are just some of the differences which separate them. Read on for more about how these fascinating creatures differ.


The first thing we notice about marine animals when diving is how they look. Squids and Octopuses are both cephalopods and share some similarities. If you look closer you will spot some difference in their appearance which separated these two animals.

Squids have ten appendages below their head. Eight of these are arms and two are tentacles, their arms have suckers on and their tentacles will have either hooks or suckers with teeth. Their head, known as the mantle, is a long triangular shape with fins at the top. Squids also have eyes which are placed in between their tentacles and head, their eyes are in line with their body and do not stick out.

Other features which you can not see or are hidden include their internal shell, which is called a pen, it is like a flexible back bone rather than a hard shell typical for some cephalopods. The smallest squid is under one inch but the largest species can reach over 40ft/13m.

Octopuses have eight appendages that are all arms covered in suckers with over 2000 suckers all together. Their mantle is round and most species do not have fins on their head, though there are some deep sea exceptions. Their eyes stick out and are placed between their head and their arms, both species have excellent eyesight but scientists believe they are colourblind.

The only hard part of an octopus is its beak, this makes it easy for octopuses to crawl through small spaces as long as their beak can fit. The smallest octopus is also under an inch and the largest species can reach up to 20ft/6m.

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Both animals enjoy warm salt water but they can be found in cooler oceans on occasion. Depending on where your driving will affect your chances of spotting either of these species, it is always good to know where they like to hang out and how they can react to perceived threats.

Squids can be found swimming in the open ocean, they can be found in schools with other squids, or living in solitude. Squids are constantly moving, when swimming at slower speeds they use the fins on their head to propel them.

If a squid feels threatened or finds themselves in the presence of a predator they will attempt to hide. Alternatively they may try to run away or swim erratically to confuse their attacker. They can also release ink to distract their predator and make a sneaky escape. Squids can live between one to five years.

Octopuses are solitary animals, they like to live near the sea bed. They can settle into the sand or find objects to hide in, whether its natural rock formations and caves or discarded waste such as plant pots or tin cans. Octopuses use their arms to crawl on the seabed or coral, they have even been known to crawl on rocks above the water to capture prey.

As a defensive mechanism, octopuses are also able to release ink. They are one of the most intelligent sea animals so have multiple defenses including imitating other sea creatures, camouflaging themselves to match their environment, using objects as protection (such as coconut shells) and flashing bright colors to warn attackers against their venomous qualities.

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Squids and Octopuses move in similar ways, this is because both species use jet propulsion to shoot through the water. When it comes to hunting and mating their behavior varies.

Squids hunt by swimming in groups in the open ocean, when they find prey they shoot their tentacles out to hook into their food. They will gradually consume their meal by breaking pieces off and eating it bit by bit. Squid’s prey includes fish, crustaceans, and occasionally other squids.

When mating, squids participate in a courtship display which often involves changing of color, once they have chosen a mate the male will pass a packet of sperm to the female who will then use it to fertilize the eggs which will be attached to rocks or coral. Usually both the male and female squids die after mating. Eggs are left defenseless and young must make their own way in the world, it takes around six weeks for squid eggs to hatch. This is dependent on species and environment.

Octopuses hunt on the seabed, they will hide and pounce on their prey or have the ability to chase their prey. They use their arms to grab victims and move it towards their beak where they will inject it with poison, paralyzing the creature, before consuming it in pieces. Their food includes clams, crabs, crustaceans, small fishes, and even other octopuses.

As octopuses are solitary creatures males can spend a lot of time searching for a mate, once found he may spread himself out to appear larger or show off his sucker to impress the female, though octopuses aren’t fussy. One of the male octopus’s arms is modified so it can deliver sperm to the female via her mantle cavity, this is used to fertilize the egg which the female will then lay in her den. The female octopus will guard her eggs until they hatch which can be between two to ten months, the mother will not leave the eggs meaning she will eventually starve to death before her offspring is born.

Need more octopus content? We have got you covered: Octopuses: 20 Amazing Facts.

Our 5 Favorite Places To Dive With Octopuses And Squids

Now you are all caught up on the differences between these fascinating species, it is time to get in the water and spot them in their natural habitat. Here are five of the best locations for diving with squids and octopuses:

1. Vancouver Island, British Columbia

If you are wanting to see the largest species of octopus then Vancouver Island is the spot. Here divers can find the Giant Pacific octopus, a species which can weigh up to 156 lbs, it changes color to reflect its mood and can often be found in dens and caves. Seeing these incredible mammoth creatures in the wild is truly a once in a lifetime experience.

2. North Sulawesi, Indonesia

This dive location is thriving with species including the Coconut octopus. This species is named due to its love of hiding in sunken coconut shells. They use the shells for protection and if they find one they really like, they will carry it with them as they crawl the sea bed. These comical sea creatures can also dramatically change color making them an entertaining spot whilst in the warm Celebes Sea.

Interested in diving in Asia? Have a look at our 10 Best Dive Spots in Asia.

3. Sea of Cortez, Mexico

Another of the largest species of cephalopods is the Humboldt squid, with mantles reaching over 1m/4ft. It is possible to spot these large creatures on a night dive from liveaboards in the Sea of Cortez off the coast of Mexico. It is definitely a dive for the adventurous and confident as these squids can become erratic when they feel threatened but even seeing these creatures from the surface is an incredible experience.

4. Anilao, Philippines

In one of the best muck dive locations in the world you can not only discover tiny macro critters but also the Wonderpus octopus. This species stands out with its white-striped brown body and spotted mantle. Apart from being extremely photogenic the Wunderpus has arms which are five to seven times longer than its body, ideal for catching prey, digging holes to hide in and making shelter from natural sea debris. Anilao is the ideal location to find this recently discovered species.

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5. Dominica, Caribbean

Caribbean Reef squids can be encountered in warm coastal waters. They are usually unafraid of divers so it is a great opportunity to see squids up close. Their mantles can reach up to 20cm in size and are often found swimming in schools. They have green and brown coloring and are able to change the color pattern of their body. Caribbean reef squids have a large population meaning high possibility of spotting them on day and night dives throughout the caribbean.

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