Bing Quiz › Trivia answers › Octopus Hearts
How Many Hearts Does an Octopus Have?
Why does an octopus need three hearts?
Octopus blood uses a copper-based protein called hemocyanin to carry oxygen instead of the iron-based hemoglobin in human blood. Hemocyanin is less efficient, especially in cold, low-oxygen water, so the octopus needs extra pumping power. The two branchial hearts each serve one gill, where the blood picks up oxygen, and the systemic heart then sends that blood to the organs and arms.
Interestingly, the systemic heart slows down or pauses when an octopus swims by jet propulsion. That is one reason octopuses prefer crawling: swimming tires them out quickly.
Why is octopus blood blue?
Hemocyanin contains copper, which turns blue when it binds with oxygen. Squid, cuttlefish, many snails and horseshoe crabs also have blue blood for the same reason.
More amazing octopus facts
Octopuses have eight arms lined with suckers that can taste what they touch. A large share of their neurons sit in the arms rather than the central brain, so each arm can react with some independence. They change color and skin texture in a fraction of a second using cells called chromatophores, and they are famous escape artists that can squeeze through any gap larger than their beak.
Mini Quiz: Test Yourself
5 quick questions on the same topic. This kind of question often shows up in the Bing Quiz.
Questions and answers
1 How many hearts does an octopus have?
- A Three
- B One
- C Two
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✓ Answer: A. Three
Did you know? Two branchial hearts serve the gills and one systemic heart serves the body.
2 What color is octopus blood?
- A Blue
- B Red
- C Green
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✓ Answer: A. Blue
Did you know? Copper-based hemocyanin turns blue when it carries oxygen.
3 Which metal is in the protein that carries oxygen in octopus blood?
- A Zinc
- B Copper
- C Iron
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✓ Answer: B. Copper
Did you know? Human hemoglobin uses iron instead.
4 What happens to the octopus's systemic heart when it swims?
- A It doubles in size
- B It speeds up
- C It slows or stops
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✓ Answer: C. It slows or stops
Did you know? That is one reason octopuses tire quickly when swimming.
5 What do octopus suckers let them do besides grip?
- A Hear
- B See
- C Taste
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✓ Answer: C. Taste
Did you know? Chemical receptors in the suckers sense what the arm touches.
Related Questions
Do octopuses have nine brains?
Not exactly. They have one central brain plus large clusters of nerve cells in each of the eight arms, which is why people sometimes say 'nine brains'.
Which other animals have blue blood?
Squid, cuttlefish, many snails and spiders, and horseshoe crabs all use copper-based hemocyanin.
How many arms does an octopus have?
Eight. Squid and cuttlefish have eight arms plus two longer feeding tentacles.