Octopuses have three hearts.

Quick Scoop

  • Total hearts: 3 in every known octopus species.
  • 1 main “systemic” heart pumps oxygenated blood to the rest of the body.
  • 2 “branchial” (gill) hearts pump blood through the gills to pick up oxygen.
  • Their blood is blue because it uses copper-based hemocyanin instead of iron-based hemoglobin.

Why so many hearts?

  • Octopuses live in often cold, low-oxygen water, so their less efficient blue blood needs extra pumping power.
  • The branchial hearts boost blood pressure through the gills, while the systemic heart focuses on the rest of the body, making circulation more efficient.

Fun extra: When an octopus swims, the main systemic heart actually pauses, which is one reason they prefer crawling along the seafloor instead of taking long swims.

TL;DR: Octopuses have three hearts: two for the gills and one for the body, all working overtime to push their blue, copper-rich blood through the water.

Information gathered from public forums or data available on the internet and portrayed here.