Infact
98 / 100
True

Octopuses have three hearts and blue blood. Two hearts pump blood to the gills, while the third circulates it to the rest of the body. Their blood turns blue because it relies on copper instead of iron to carry oxygen.

Infact verdict: True (98/100).

The claims about octopuses having three hearts, blue blood, and the specific functions of these hearts are well-supported by multiple reliable sources. Octopuses have three hearts: two pump blood to the gills, and one circulates it to the rest of the body. Their blood is blue due to the presence of hemocyanin, a copper-based protein. These facts are corroborated by educational and scientific sources, confirming the accuracy of the claims.

October 04, 2026 Language: en 5 claims analyzed
How is this score determined? →

Individual claims

100
True Science
Octopuses have three hearts.
Multiple reliable sources, including Smithsonian Magazine and Study.com, confirm that octopuses have three hearts. Two hearts pump blood to the gills, and one circulates it to the rest of the body.
Fact Check Score None
Fact Check Weight 0
Web Consensus Score 100
Web Consensus Weight 40
Source Quality Score 100
Source Quality Weight 20
Llm Reasoning Score 100
Llm Reasoning Weight 40
Llm Reasoning Score Raw 100
Weighted Total 100
Evidence Summary 3 web sources confirm octopuses have three hearts.
100
True Science
Octopuses have blue blood.
The claim is supported by multiple sources, including MarinePatch and ScienceABC, which explain that octopuses have blue blood due to hemocyanin, a copper-based protein.
Fact Check Score None
Fact Check Weight 0
Web Consensus Score 100
Web Consensus Weight 40
Source Quality Score 100
Source Quality Weight 20
Llm Reasoning Score 100
Llm Reasoning Weight 40
Llm Reasoning Score Raw 100
Weighted Total 100
Evidence Summary 3 web sources confirm octopuses have blue blood.
96
True Science
Two hearts pump blood to the gills in octopuses.
The claim is corroborated by multiple sources, including Study.com and Facebook posts, which describe the function of the two branchial hearts in octopuses.
Fact Check Score None
Fact Check Weight 0
Web Consensus Score 95
Web Consensus Weight 40
Source Quality Score 95
Source Quality Weight 20
Llm Reasoning Score 95
Llm Reasoning Weight 40
Llm Reasoning Score Raw 95
Weighted Total 96
Evidence Summary 2 web sources confirm two hearts pump blood to the gills.
96
True Science
The third heart in octopuses circulates blood to the rest of the body.
The claim is supported by evidence from sources like the National Aquarium and Facebook posts, which describe the systemic heart's role in circulating oxygenated blood throughout the body.
Fact Check Score None
Fact Check Weight 0
Web Consensus Score 95
Web Consensus Weight 40
Source Quality Score 95
Source Quality Weight 20
Llm Reasoning Score 95
Llm Reasoning Weight 40
Llm Reasoning Score Raw 95
Weighted Total 96
Evidence Summary 2 web sources confirm the third heart circulates blood to the body.
96
True Science
Octopus blood turns blue because it relies on copper instead of iron to carry oxygen.
The claim is confirmed by multiple sources, including Instagram and Facebook, which explain that octopus blood is blue due to hemocyanin, a copper-based protein.
Fact Check Score None
Fact Check Weight 0
Web Consensus Score 95
Web Consensus Weight 40
Source Quality Score 95
Source Quality Weight 20
Llm Reasoning Score 95
Llm Reasoning Weight 40
Llm Reasoning Score Raw 95
Weighted Total 96
Evidence Summary 2 web sources confirm octopus blood is blue due to copper.

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