So, you were wondering if a squid can either be categorized as a fish, a shellfish, or a mammal? This ten-armed elongated sea animal is pretty interesting and confusing at the same time.
In this article though, the answer to this question will become clear to you and after answering this question I’ll also answer a few more closely related questions, so make sure you keep on reading.
Is squid considered a fish, a shellfish, or a mammal? The characteristics of a squid fit the category of neither fish nor mammals. Essentially, a squid belongs to the Cephalopods category which is a group of mollusks. Mollusks belong to the shellfish category and therefore squid can be categorized as shellfish as well.
Unlike other shellfish or mollusks, squid does not have outer shells. Excellent examples of animals that belong to the shellfish group include snails, oysters, and clams.
However, squid does share several characteristics that justify their identity as mollusks. Generally, animals that fall under the Mollusca category have soft bodies with a ‘head’ and ‘foot’ region (their bodies are bilaterally symmetrical).
More often than not, their bodies are covered by a tough exoskeleton which is located in the place where the shells of other shellfish can be found.
It may therefore be quite easy to incorrectly categorize them as fish due to their tiny internal skeleton, a cartilaginous structure otherwise known as the pen.
Check out the video below if you want to find out how squids lost their shells through evolution.
Is a squid a mollusk?
Biologically, squid is categorized as a Cephalopod which is a class that falls under the Phylum Mollusca. They include pearly chambered Nautilus, octopuses, and squids. Therefore, squids are considered to be mollusks.
The Phylum Mollusca is quite diverse and undisputedly the predominant phylum in the marine world, making up twenty-three percent of known marine species.
Although most animals in this group belong to the sea like the squid, they also inhabit freshwater and terrestrial habitats.
Why are squids considered mollusks?
Squids are considered mollusks because most of their characteristics fit the description of what is required to call an animal a mollusk. The most prominent features of squid that are similar to other animals in this group are their soft bodies and their hard exoskeletons.
Mollusks, also known as mollusks, are soft-bodied invertebrate animals. Mollusc species are divided into three subcategories, namely, Gastropoda, Bivalvia, and Cephalopoda. The most diverse group of the three is the Gastropoda, and a good example of an animal that belongs to this group is a snail.
On the other hand, the second group, Bivalvia, consists of clams, oysters, and mussels. They are unique for their double shells that close up tightly together for protection.
Finally, the group Cephalopoda, which consists of squids and octopuses which have no shells, and instead, some animals that belong to this group have a hard exoskeleton.
They are relatively larger than the animals that belong to the other two groups, more intelligent, and feed on fish, crustaceans, and other mollusks.
Why is squid not considered fish?
One of the main characteristics of squids that rule them out as fish is that they are invertebrates, whereas fish belong to the phylum Chordata, which is made up of vertebrates. Therefore squids already do not contain all the characteristics to qualify them as fish.
Vertebrates refer to animals that have spinal cords and bones. Squids which are invertebrates have soft bodies.
Additionally, fish can live in all water depths but dominate the surface where there is more oxygen. However, squids predominantly live at greater depths where the oxygen supply is relatively lower.
You already know by now that squids are considered to be shellfish and that they’re not seen as fish or mammals. But do you also want to find out what squid meat tastes like? If this is the case then you should check out the article: “What Does Squid Meat Taste Like? (Everything You Need To Know)” which will give you the answer to this question and also answers to many more closely related questions.
Why are squids considered shellfish?
Since squids are members of the class Cephalopoda which is a subcategory of mollusks, they are also classified as shellfish. Squids also contain several characteristics that are similar to the characteristics of other shellfish species, such as the rigid exoskeleton.
There are two primary categories of shellfish which are called crustaceans and mollusks. Crustaceans include shrimps, lobsters, and prawns, whereas mollusks include clams, oysters, mussels, and squids.
Squids may not have defined shells like most of these animals, but they have a hard outer skin that serves as a shell.
Why are squids not considered mammals?
Squids are not mammals since their characteristics are not similar to those of mammals. Major features that are visible in mammals are that they have fur, are warm-blooded, and most importantly, that they are vertebrates which are all characteristics that cannot be found in squids.
Mammals belong to the Phylum Chordata, which means that they have spinal cords contrary to squids which belong to the phylum Mollusca and have no spinal cords. These two categories exhibit a massive disparity in characteristics.
For example, mammals are warm-blooded and hairy, whereas mollusks are cold-blooded, and have no hair.
What is a squid characterized as?
Squids are characterized as Cephalopods. Cephalopods are members of the class Cephalopoda (one of the three groups that fall under the phylum Mollusca). Cephalopoda is the least populous of the three groups but consists of highly advanced, intelligent, and exclusively marine animals.
Animals that fall under this category are characterized by their high speed, furious appetite, and poisonous nature.
Representatives of this group, such as the pearly chambered Nautilus, squid, and the octopus, have a mouth at the center of several tentacles that are located under their strong head and body structure.
What phylum is the squid in?
Squids are representatives of the phylum Mollusca and fall under a small group referred to as the class Cephalopoda. Other familiar members of this group are the pearly chambered Nautilus and the octopus.
Other animals that fall under the phylum Mollusca include snails and clams but these animals fall under different subcategories named Gastropoda and Bivalvia respectively.
Most animals that fall under the phylum Mollusca are often bilaterally symmetrical and have soft unsegmented bodies that are covered by a mantle and shell for protection.
Related questions
What is the scientific name of a squid?
The general scientific name for a squid is Teuthida. However, there are up to hundreds of squid species with each variant having a different scientific name. The scientific name Teuthida is sourced from a Greek word that means fierce. Other names for squid include Nototodarus gouldi and Calamari.
Is squid fishy?
Fresh squid is not fishy. If it appears dull, wrinkled, or smells fishy, it may not be fresh and should never be eaten. Ideally, fresh squid looks smooth and shiny and has a mild smell of the sea. When cooked, fresh squid should be firm, a bit chewy, and should not be slimy.
Is squid fish halal?
Most Islamic scholars consider squid halal together with octopuses. These two animals are sea creatures, and since Allah has made every harmless creature from the sea halal, you can be sure that squid is certainly halal as well.
Check out the video below to see which other seafoods are considered to be halal.
Conclusion
In a nutshell, squids are neither fish nor mammals but are shellfish by the trait of belonging to the phylum Mollusca. They belong to the shellfish category because they do contain all the characteristics that are required to classify them as shellfish.