If you love seafood, you've probably eaten squid, octopus, or cuttlefish before. But have you ever wondered what makes them different? They all have big eyes, flexible tentacles, and soft bodies, yet each has unique features that set them apart.

Understanding these differences isn't just interesting—it also helps us appreciate these incredible creatures beyond just seeing them as food. So, Lykkers, let's dive into the fascinating world of these ocean wonders!

Body Shape: The Easiest Way to Tell Them Apart

One of the quickest ways to identify these animals is by looking at their body shape.

• Octopuses have round, ball-like bodies with no rigid structure inside. This allows them to squeeze through tiny spaces, making them masters of escape.

• Cuttlefish (or "true" cuttlefish) have a wider, oval-shaped body with a thick, chalky internal shell called a cuttlebone.

• Squid, also known as calamari, have a longer, cone-shaped body, making them more streamlined for fast swimming.

If you've eaten calamari rings, they came from the body of a squid!

Counting Tentacles: 8 or 10?

Another key difference is the number of arms and tentacles.

• Octopuses have eight long arms with rows of suckers. They don't have extra tentacles. This is why they're sometimes called "eight-armed creatures."

• Squid and cuttlefish both have ten appendages—eight shorter arms and two long tentacles that they use to grab food. These extra tentacles are usually hidden inside small pockets and shoot out like elastic bands when catching prey.

If you see a sea creature with just eight arms, it's an octopus. If it has two extra long tentacles, it's either a squid or a cuttlefish!

Suckers and Hooks: How They Grip

Now, let's look at their suckers.

• Octopuses have soft suckers arranged in either one or two rows. These suckers can create a strong grip, allowing an octopus to pry open shells or even twist bottle caps!

• Cuttlefish have multiple rows of small suckers, but they lack the hooks or hard rings that squids have.

• Squid often have sharp, hook-like structures on their suckers, which help them latch onto slippery prey.

If you see tentacles covered in tiny hooks, it's definitely a squid!

The Secret Hidden Inside: Their Internal Shells

Even though they all look soft, their internal structures are quite different.

• Octopuses don't have an internal shell at all, which is why they're so flexible.

• Squid have a thin, transparent "pen" inside their bodies. This helps them stay rigid while swimming.

• Cuttlefish have a thick, chalky cuttlebone inside. This cuttlebone helps them control their buoyancy by adjusting the gas and liquid inside it.

Ever seen a cuttlebone in a pet bird's cage? That comes from a cuttlefish!

How They Move: Speed vs. Stealth

All three animals move using a jet-propulsion system—drawing in water and shooting it out forcefully. However, their movement styles differ:

• Squid are the fastest swimmers, using their streamlined bodies and fins to dart through the water.

• Cuttlefish are slower but move gracefully, using their side fins like little wings.

• Octopuses prefer crawling along the ocean floor, squeezing into tiny crevices rather than swimming.

If you see one quickly shooting through the water like a torpedo, it's likely a squid. If it's gliding smoothly, it's a cuttlefish. And if it's creeping along the seabed, that's an octopus!

Masters of Disguise: Who's the Best at Hiding?

All three species are experts in camouflage, but some have special tricks:

• Octopuses can change color and even texture, making them the ultimate escape artists. Some species can mimic other sea creatures to confuse predators.

• Cuttlefish have advanced color-changing abilities, even displaying hypnotic patterns to distract prey.

• Squid can change color too, but they use it more for communication rather than hiding.

If you see a sea creature suddenly disappearing into its surroundings, it's most likely an octopus or cuttlefish!

The Amazing Glow: Bioluminescent Species

Some deep-sea squid and cuttlefish have the incredible ability to glow in the dark! They use tiny light-producing cells or bacteria to create flashes of light, helping them communicate, attract mates, or scare off predators.

One of the most famous glowing species is the firefly squid, which lights up in beautiful blue patterns in the waters of Japan. While bioluminescence is rare in octopuses, many squid species rely on this trick to survive in the dark depths of the ocean.

Why It's Important to Know the Difference

Understanding these differences helps us appreciate these creatures beyond just their role as seafood. Many squid, octopus, and cuttlefish populations are declining due to overfishing. Some species, like the Japanese flying squid, are facing serious population declines. By learning more about them, we can help ensure their survival for future generations.

So next time you see one on a menu—or better yet, in the ocean—you'll know exactly what you're looking at. Which of these incredible sea creatures do you find the most fascinating, Lykkers? Let's hear your thoughts!