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The giant squid's eyeballs are about 10.5 inches (26.67 cm) in diameter, about the size of a football!
There are about 300 different kinds of squid. They are found in all oceans around the world, including the icy Antarctic waters. They eat a variety of different foods, including small animals like krill, some fish, and even each other. Squid typically live 3 to 5 years, but some large squid have been known to live as long as 15 years. Although they share some things in common with octopuses, squid and octopuses are completely different animals.
5 Squid Facts
- Some squid have special cells in their skin that allow them to change color.
- Most squid have 8 hands and two longer tentacles, but some have 10 hands.
- Squids have strong beaks that they use to kill and eat their prey.
- Many squid that live in deep water have bioluminescent organs that display through their skin.
- Squids are one of the few animals with multiple hearts. The squid has three hearts in total!
You can check out more incredible facts about squid here.
Because of the wide variety of squid species, they have hundreds of different scientific names. They are both cephalopods, which means they belong to the same scientific group of cephalopods as octopuses and cuttlefish. The class name comes from the Greek words for head and foot. They are members of the order Decapod, which is derived from the Greek word for 10 feet. Squids belong to the order Teuthida, a term derived from the Greek word meaning "fierce".
appearance and behavior
The appearance of squid can vary from species to species, but in general, all squid have an elongated, tubular body called a mantle that is slightly flattened at the end. On either side of the mantle are fins that help the squid move through the water. Depending on the species, these fins can be very large and run through the entire mantle, or very small and located at only one end. Squids also have relatively large eyes, one on each side of the head, that allow for 360-degree views of their surroundings.
At the lower end of the squid's body are arms and tentacles, which are connected to the head. There are suction cups on each arm, as do the tentacles. Some squid also have sharp hooks on their suckers that allow them to hold on to their prey. They don't have bones like us, but cuttlefish do have a small internal skeleton made of chitin, the same thing you find on the outside of insects.
The squid's shape allows it to glide quickly through the water. When it's swimming slowly, it uses its fins to propel, but if the squid is in a hurry, it sucks in water through its mantle and then ejects the water through a siphon, thus jetting through the water. The siphon can be moved in any direction, allowing the squid to move as fast as it chooses.
Squid are usually black, white, brown or gray, but many of them can change their appearance at will. Humboldt squid, for example, can flash red and white lights, and other squid can match their colors to their surroundings or display colorful patterns on their bodies. They can use color to signal to other squids or to help camouflage themselves from predators.
Deep-sea squid often have bioluminescence organs, these glowing body parts that can be seen from the outside of the animal. Usually, $squid also spews a glob of ink when it feels threatened. Ink hides them, giving them time to escape to safety. A notable exception is the vampire squid, which spews a sticky bioluminescent cloud into the water that glows for about 10 minutes, giving the squid time to escape.
Squid come in many different sizes. The heaviest squid ever recorded was a giant squid found in New Zealand in 2007. Weighing more than 1,000 pounds (453.6 kilograms), this huge animal is almost as heavy as a grizzly bear. The longest squid ever found is a giant squid. While not as heavy as a giant squid, the largest giant squid is 49 feet (14.9 meters) long, longer than a semi. Most squid are much smaller, averaging about 2 feet (60 centimeters) long, about the size of an average human being. The smallest known squid is the southern dwarf squid, which is only ¾ inch (1.6 cm) long and barely visible.
Squid tend to live alone, but they also sometimes come together in packs, and some of them even hunt cooperatively, similar to how wolves hunt. When they congregate, groups of squid are called shoals or squads, with the exception of giant squid. A group of giant squid is called a school.
History and Evolution
Squids are believed to have evolved between 50 and 60 million years ago from shelled molluscs, the ancestors of the animals we see today. Even more interesting, they also seem to have evolved from prehistoric snails. It may have sidestepped the question of where the snail shells disappeared, but leftover shells, or signs of them, have been found in other animals with a common ancestor. They're like little clues for investigating the family trees of past animal species. From such evolutionary evidence, it can be seen that cuttlefish have something called a cuttlebone, which is a leftover clue that they have a shell. Nautili also has internal and external examples of remaining shells.
Another fascinating feature of squid evolution is how they have grown eight arms and two tentacles. Scientists have found evidence that these highly useful appendages are actually very similar to the feet of snails and other similar bivalves. Squids amazingly adapted and evolved their unique feet into what we know today.
Types of squid
There are hundreds of different types of squid in the world. These are just some of them!
- Giant Squid – Giant squid are very large, weighing at least 1,090 pounds and are estimated to be between 30-33 feet in length. This size makes the giant squid the largest squid in the world. Giant squid are thought to ambush predators and use bioluminescence to attract prey. These squid are believed to inhabit primarily the Southern Ocean around Antarctica, down to depths of 13,000 feet. Because they live at such extraordinary depths, there is still a lot to learn about these creatures.
- Vampire Squid – Vampire squid typically live in the deep sea, using bioluminescent organs and oxygen metabolism to survive in extremely low-oxygen waters. This sea creature resembles both a squid and an octopus. However, it is neither. It has eight arms and two tentacles. The vampire squid gets its name from its dark color and the skin that connects its multiple arms – forming a cape-like structure. Vampire squid have two filaments. However, these sea creatures can only extend a single filament that helps these fish overcome the energy deficit in areas with low oxygen concentrations.
- Humboldt Squid – The Humboldt squid, commonly known as the giant squid, can grow up to 110 pounds and reach a maximum length of 7 feet. Found in the eastern Pacific Ocean, this squid is the largest of the flying squid. They are most commonly found in large flocks of about 1,200 individuals at depths between 660 and 12,300 feet. They can swim at speeds of up to 15 miles per hour and are ferocious predators. They mainly feed on other molluscs, small fish and crustaceans, but are also frequent cannibals. To chase prey, the Humboldt squid chases and attacks with its barbed tentacle suckers. They then use their sharp, parrot-like beaks to tear open the flesh of their prey. Each sucker has a ring of sharp teeth, and the squid's beak can easily tear through tough tissue. There are verified reports of man-made attacks, mainly against deep-sea divers.
- Bigfin Reef Squid – The Bigfin Reef squid, also known as the flash squid or oval squid, belongs to the loliginid squid family Loliginidae. They get their name from the large elliptical fins attached to the mantle. Although they are a medium-sized species, measuring only about 1.5 to 13 inches in length, they outgrow almost any other large marine invertebrate. They put on elaborate mating displays and have a relatively short life span of up to 315 days.
- Robust Clubhook Squid – The Robust Clubhook Squid
- Giant Squid – Estimated to weigh 606 pounds and reach a length of 39-43 feet, the Giant Squid is the longest squid in the world. Giant squid inhabit depths of approximately 989-3,280 feet, making them very difficult to study. Few of them have been studied in vivo, and most of what is known about them comes from studies of dead bodies washed up on beaches. The giant squid's diet includes deep-sea fish, other smaller squid, and possibly some whales. The giant squid is a solitary hunter, capturing prey with two tentacles with barbed suction cups.
- Heterololigo squid – Heterololigo squid, also known as squid, is a genus of only Heterololigo bleekeri. Known for its short tentacles, it only lives about a year. Japanese fishermen catch these off their coasts.
- Sword Tip Squid – The sword tip squid, Uroteuthis edulis, is a squid commonly found in the southern part of the East China Sea. They live for only nine months and spend most of their time migrating depending on sea temperature.
Squid are found in oceans all over the world. Not all species live anywhere in the world. Some squid prefer warm tropical waters, while others thrive in colder waters, where krill and other food can be found, but as a species, they are found almost everywhere.
Unlike octopuses, which live in the corners of rocks and coral reefs, squid are free-swimming and don't look for a place to call home, though some of them do live near the bottom of the ocean, which helps them hide from enemies.
In most cases, squid eat fish such as orange snapper, lanternfish, and northern perch, as well as other sea life such as oysters, crab, and shrimp. Squids are also cannibals and will happily devour another squid, even one of the same species, if they are hungry. The size of the prey depends on the size of the squad.
Humboldt squid are known for their aggressive nature and will eat anything they can get their hands on. There are even stories that when the squid appear, they attack and eat fishermen who are unfortunate enough to fall into the water.
The vampire squid is different from most other squid in that it does not catch and eat live food, nor does it drink blood as its name suggests. Instead, it floats in the water waiting to catch debris that falls from the water. It consists of tiny animal carcasses and the feces of other living things. The squid then rolls everything it catches into a ball, sticks it together with mucus, and eats the ball it made.
Predators and Threats
Because squid come in a wide range of sizes and can be found almost everywhere, many species of animals eat squid. Baby squid are eaten by almost any predator imaginable, but their main predators are penguins, seals, sharks such as gray reef sharks, whales such as sperm whales, and humans.
Despite being a popular prey item, squid are still abundant in the wild. According to the International Union for Conservation of Nature (IUCN), squid are classified as Least Concern, meaning there is no immediate threat to squid known to exist, and they are abundant in the wild.
At least some types of squid have the ability to regenerate tentacles, so if the tentacles are lost in a predator attack or otherwise, $squid can eventually replace the missing parts. Scientists don't believe squid can regrow their arms. Only their longer tentacles appear to have the ability to regenerate.
Overall, squid are a food source for humans and are threatened by overfishing. In places like Japan, where squid is consumed as a cultural staple, it is included in sushi dishes. In Western cultures it is known in Italian as calamari and is used for stuffing, sliced rings or flat slices.
Areas where squid are caught include the North Pacific, the Mediterranean, the East Coast of the United States, and the Northeast Atlantic. It contains vitamins and nutrients that are beneficial to the human body, namely copper, manganese, zinc, selenium, vitamin B12 and riboflavin.
Reproduction, Babies and Longevity
Because there are so many species of squid, there are some differences in how they reproduce and how long they live. Typically, squid mate in groups, and reproduction occurs when the male deposits sperm into the female's mantle. She can then store the sperm until she is ready to use it. When the time is right, the female uses sperm to fertilize her eggs, which she then lays on the seafloor or attaches to algae. She doesn't care about them anymore.
When the eggs hatch, the larvae often look like tiny replicas of the adults and are called paralarvae. They grow and change as they mature, eventually becoming squids that can take care of themselves. Baby squid absorb the yolk initially, which feeds them until they can hunt on their own.
Squid lifespans are somewhat uncertain, but scientists believe most don't live more than 5 years in the wild, and many don't even live that long. The only exceptions are the larger squid that live in the depths of the ocean, some of which are known to live up to 15 years. Most species die after breeding.
It is impossible to know the total number of all squid species, but they are in the millions. The IUCN lists them as a species of least concern, meaning squid are not considered threatened or endangered in any way. The decline in squid numbers could spell disaster for many other species, since so many creatures depend on squid for survival. For example, a single sperm whale can eat up to 800 squid in a day, and elephant seals may consume large amounts of squid as a significant part of their diet.
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about the author
Heather Ross is a middle school English teacher and mother of 2 people, 2 tuxedo cats and a golden doodle. In between taking the kids to soccer practice and grading homework, she loves reading and writing about all things animals!
Squid FAQs (Frequently Asked Questions)
Is the squid delicious?
Many people in the world eat squid. It can provide excellent nutrition, but how good it is for you depends on how it is prepared. A 3-ounce serving of raw squid has only 78 calories and 15 carbohydrates. It also contains 13.2 grams of protein, as well as several essential vitamins and minerals, including copper, selenium, zinc, phosphorus, niacin, and B-12. Frying it more than doubles the calories while slightly increasing the protein, but it doesn't add much else.
Are octopus and squid the same thing?
While they may have some similarities in appearance, octopus and squid are not the same thing. They have different lifestyles, octopuses live in a single den, while squid swim in the open ocean and can be found in large schools of squid known as shoals. Furthermore, the squid has eight arms, two tentacles, and a pair of fins located on its elongated mantle, while the octopus has eight tentacles, no fins, and a rounded head.
is squid a fish
No, squid is not a fish. Fish are members of the phylum Chordata, which contains vertebrates. They have spinal cords and bones. Squids are members of the phylum Mollusca, which contains invertebrates. They have no spinal cord or bones. Squid are cephalopods, which means they have arms attached to their heads. Fish do not have this structure.
How many tentacles does a squid have?
A squid may look like it has 10 tentacles, but it actually has 8 arms and two tentacles. The squid grabs its prey with its tentacles, then uses its arms to hold and control the prey. Its tentacles are much longer than its arms, and it is often seen trailing the squid as it swims.
Can you eat squid ink?
Yes, squid ink is used in many foods, and it's delicious. It is used to make black pasta and is also used in seafood sauces and some sushi dishes. Squid ink is good for you because it contains antioxidants, iron, and many other nutrients. It is black because it contains melanin, which is also the substance that gives human skin its pigment. A little of it can add a lot of flavor to food.
Are squid carnivores, omnivores, or herbivores?
Squid are carnivores, eating only meat, including fish and shellfish.
To which kingdom do squid belong?
Squids belong to the animal kingdom.
What phylum do squid belong to?
Squids belong to the phylum Molluscs.
Which category do squid belong to?
Squid belong to the cephalopod class.
What family do squid belong to?
Squids belong to the Oegopsina family.
What order do squid belong to?
Squids belong to the order Teuthida.
What type of mulch do squid have?
Squid is covered with a smooth skin.
What type of habitat do squid live in?
Squid live in cool and temperate waters.
What is the squid's main prey?
Squid prey on fish, crab and shrimp.
What are the natural enemies of squid?
Predators of squid include humans, seals and whales.
What is the average litter size for squid?
The average litter size of squid is 5.
What interesting facts about squid?
Some squid species are known to have 10 arms!
What is the scientific name of squid?
The scientific name of squid is Teuthida.
How long do squid live?
Squid can live from 5 to 30 years.
How fast is a squid?
Cuttlefish can travel at speeds of up to 18 miles per hour.
What is the difference between cuttlefish and squid?
Cuttlefish are much smaller than squid, and they also have fans on the sides of their heads, which squid usually don't. Read all about their differences here!
Thanks for reading! Have some feedback for us? Contact the AZ Animals editorial team.
- David Burnie, Dorling Kindersley (2011) Animals, The Definitive Visual Guide to the World's Wildlife
- Tom Jackson, Lorenz Books (2007) Encyclopedia of World Animals
- David Burney, Kingfisher (2011) The Animal Encyclopedia of Kingfishers
- Richard Mackay, University of California Press (2009) Atlas of Threatened Species
- David Burnie, Dorling Kindersley (2008) Illustrated Animal Encyclopedia
- Dorling Kindersley (2006) Dorling Kindersley Animal Encyclopedia