three hearts · All Facts

three hearts
An octopus has three hearts and blue blood — two hearts pump through the gills; copper-based hemocyanin turns the blood blue when oxygenated.
SrcSmithsonian Ocean

Next evidence →more than a mile of waterIf you set Mount Everest on the floor of the Mariana Trench's Challenger Deep, its peak would still sit under more than a mile of water.

More packs

Dino
Body
Weird
Animals
Snakes
Insects
Ocean
Hidden Gems
Space
Mummies

More in Ocean

more fish biomass than the rest of the ocean combinedThe ocean twilight zone (200–1,000 m) may hold more fish biomass than the rest of the ocean combined.
2.5 centimeters per yearThe Mid-Atlantic Ridge spreads at about 2.5 centimeters per year — roughly the rate human fingernails grow.
just larger than its beakAn octopus's only hard part is its beak — so it can squeeze through any opening just larger than its beak.
2,240 suckersA female giant Pacific octopus carries about 2,240 suckers; each sucker holds roughly 10,000 chemoreceptor cells.

Open full Ocean pack →

← Back to evidence