Head to head
Common Octopus vs Giant Squid
Octopuses and squid are both cephalopods — soft-bodied molluscs with a beak, a funnel, and colour-changing skin — but they have evolved for very different lives. The octopus is a den-dwelling bottom crawler and escape artist; the squid is a fast, streamlined open-water swimmer that hunts in packs.
| Common Octopus | Giant Squid | |
|---|---|---|
| Arms and tentacles | 8 arms, no tentacles | 8 arms plus 2 longer feeding tentacles |
| Body shape | Rounded, baggy, no fins | Streamlined torpedo with fins at the rear |
| Internal support | None — only the beak | A stiff internal "pen" (gladius) |
| Where it lives | On and around the seabed; dens in crevices | The open water column, surface to the deep sea |
| Lifestyle | Mostly solitary; active forager | Many species school; some hunt cooperatively |
| Speed | Slow crawler; brief jet bursts | Fast, sustained jet swimming; some "fly" above the surface |
| Size range | A few cm to ~5 m arm span (giant Pacific octopus) | A few cm to ~13 m (giant squid), heavier still in the colossal squid |
| Lifespan | 1–2 years (up to 3–5 in the largest) | Often under 1 year; ~5 years in giant squid |
| Intelligence | Tool use, jar-opening, maze-solving, individual recognition | Fast learners, complex signalling, less studied |
Octopus vs Squid: common questions
How do you tell an octopus from a squid?
Count the limbs and look at the body. An octopus has eight arms and no tentacles, a rounded head-and-body with no fins, and it tends to crawl on the bottom. A squid has eight arms plus two longer feeding tentacles (ten limbs in total), a long tapering body with a pair of triangular fins, and it swims in open water. Squid also keep a stiff internal support called a pen; octopuses have no hard parts except the beak.
Which is smarter, an octopus or a squid?
Octopuses are the more famous problem-solvers — opening containers, using tools, escaping tanks, and recognising individual people — and they have been studied far more. Squid are clearly intelligent too, with fast learning and elaborate skin-signalling used to communicate within schools, but their cognition is less well understood. On current evidence the octopus edges it.
Which is bigger, the giant squid or the giant Pacific octopus?
The giant squid is longer — up to around 13 metres including its feeding tentacles, versus roughly 5 metres of arm span for the largest octopus. The octopus is bulkier for its length. The heaviest cephalopod of all is the colossal squid, which is shorter than the giant squid but much more massive.