FaunaHub

Octopus

MolluskCephalopodMarine Invertebrate

Common octopus (Octopus vulgaris) in shallow water at the Arrábida Natural Park, Portugal.

Common octopus (Octopus vulgaris) photographed in Portugal.

Image: Diego Delso, CC BY-SA 4.0, via Wikimedia Commons.

Overview

Octopuses are cephalopod molluscs of the order Octopoda — soft- bodied marine animals with eight arms covered in suckers, a sharp beak, and a highly developed nervous system relative to other invertebrates. The common octopus (Octopus vulgaris) is one of the most widely distributed and commonly cited reference species.

Habitat & Range

Octopuses occupy a very wide range of marine habitats — from shallow rocky reefs and intertidal pools to the deep sea. Different species occupy specific habitat niches; the common octopus is typically found on coastal rocky bottoms in temperate and tropical waters.

Diet

Octopuses are carnivorous predators. The common octopus feeds mainly on crustaceans, bivalves, and small fish, using its beak and salivary glands to subdue prey. Foraging behaviour is often nocturnal and may involve probing crevices with the arms.

Behavior

Octopuses are known for sophisticated behaviour relative to other invertebrates. Documented abilities include rapid camouflage using chromatophores and skin texture, escape from laboratory enclosures, manipulation of objects, and — in some species — apparent use of coconut shells or other materials as shelter. The cephalopod nervous system is unusual in that substantial neural tissue is distributed throughout the arms.

Human Interaction & Conservation

Octopuses are commercially fished in many regions and feature in food cultures around the world. Modern animal-welfare and scientific discussion increasingly takes into account cephalopod cognition; several jurisdictions now legally recognise octopuses as sentient for research-ethics purposes. FaunaHub does not provide guidance on keeping octopuses; their husbandry is highly specialised and is best left to public aquaria and qualified researchers.

Similar Animals

Other cephalopods include squid, cuttlefish, and the chambered nautilus. All share the basic cephalopod body plan with a prominent head, arms or tentacles, and a beak, but octopuses differ in lacking an internal shell or pen and in having only eight arms.

Frequently Asked Questions — Octopus

Why do octopuses change colour?
Octopuses use specialised skin cells — chromatophores, iridophores, and leucophores — to change colour and pattern rapidly. The behaviour is used for camouflage, communication during courtship or conflict, and apparent stress signalling. Notably, octopuses are believed to be largely colourblind, raising open scientific questions about how they match background colours.
Are octopuses intelligent?
Octopuses show some of the most striking behavioural complexity documented in invertebrates: maze learning, tool-like use of materials, and rapid problem solving in captive studies. Whether 'intelligent' is the right framing is contested; authoritative summaries are available from sources such as Animal Diversity Web and Britannica.
How long do octopuses live?
Most octopus species are surprisingly short-lived — often one to a few years — and typically die shortly after reproduction. Lifespan varies by species and is generally far shorter than many other large marine animals.
Are octopuses dangerous?
Most octopus species are not dangerous to humans during ordinary encounters, but all octopuses are venomous to some extent — used to subdue prey — and the small blue-ringed octopuses of the Indo-Pacific carry tetrodotoxin and can be deadly. Treat any encounter with caution and follow local marine-safety guidance.

Sources and further reading

Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.