Where does this come from, and can I check it?

Two pump blood to the gills and one pumps it around the body. The figure is taken from Monterey Bay Aquarium, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a animals fact?

Yes. It sits on the Animals shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

An octopus has three hearts

Two pump blood to the gills and one pumps it around the body.

The two branchial hearts push blood through the gills to pick up oxygen, and the single systemic heart sends that oxygenated blood around the body. Octopus blood is blue because it uses copper-based haemocyanin instead of iron-based haemoglobin.

Octopus vulgaris.001 - Aquarium Finisterrae — Fernando Losada Rodríguez · CC BY-SA 4.0 · licence · source

Where this comes from

Monterey Bay Aquarium

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Tags: octopus, ocean, blood

An octopus has three hearts: the short answers

Where does this come from, and can I check it?: Two pump blood to the gills and one pumps it around the body. The figure is taken from Monterey Bay Aquarium, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a animals fact?: Yes. It sits on the Animals shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.