common Atlantic octopus vs Green Sea Turtle

Octopus vulgaris compared with Chelonia mydas

Key Differences

• common Atlantic octopus is Not Evaluated while Green Sea Turtle is Endangered.
• common Atlantic octopus is carnivore while Green Sea Turtle is herbivore.
• Green Sea Turtle is 40.0x heavier than common Atlantic octopus.
• Green Sea Turtle lives longer (80 years vs 2 years).

Taxonomic Classification

Rank	common Atlantic octopus	Green Sea Turtle
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Cephalopoda (Cephalopods)	Reptilia (Reptiles)
Order	Octopoda (Octopuses)	Testudines (Turtles & Tortoises)
Family	Octopodidae (Common Octopuses)	Cheloniidae (Sea Turtles)
Genus	Octopus (Octopuses)	Chelonia (Green Sea Turtles)
Species	Octopus vulgaris	Chelonia mydas

Evolutionary Relationship

common Atlantic octopus and Green Sea Turtle share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

common Atlantic octopus

NE — Not Evaluated

Trend: Stable →

Green Sea Turtle

EN — Endangered

Population: ~85.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	common Atlantic octopus	Green Sea Turtle
Diet	Carnivore	Herbivore
Average Lifespan	2 years	80 years
Average Length	60 cm	1.2 m
Average Weight	5.0 kg	200.0 kg

Habitat & Geographic Range

common Atlantic octopus

Habitat

Typically found in diverse ecosystems where prey species are available.

Range

Distributed across Chile, Denmark, Norway, Portugal, and Sweden.

Green Sea Turtle

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 8 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Distributed across Australia, Brazil, Costa Rica, Indonesia, and Mexico. Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

common Atlantic octopus

One of the most studied invertebrates in neuroscience and behavioral biology, common octopuses inhabit rocky reefs and seafloors in tropical and temperate coastal waters globally. Highly intelligent with distributed nervous systems — two-thirds of their 500 million neurons reside in their arms — they demonstrate tool use, problem-solving, and individual personalities. Masters of camouflage, they change skin color and texture in milliseconds. They have three hearts, blue copper-based blood, and extremely short lifespans of 1–2 years.

Green Sea Turtle

The green sea turtle is one of the largest sea turtles. They are named for the green color of their cartilage and fat, not their shells.