How many hearts does an octopus have? Anatomy facts about the tentacled sea creatures
More than just aquarium must-sees, octopuses are known for being highly intelligent creatures and, at times, even friends to humans.
These connections are the subjects of the popular 2020 documentary “My Octopus Teacher,” the book “The Soul of an Octopus” and Shelby Van Pelt’s humorous fiction novel “Remarkably Bright Creatures,” which features a widower’s unlikely friendship with a mischievous octopus.
But are these creatures as remarkable, bright and unique as popular media makes them seem? Here’s everything you need to know.
How many hearts does an octopus have?
Octopuses have three hearts. One heart pumps blood throughout the body and the other two move blood to the gills, according to the nonprofit National Wildlife Federation.
Like some other marine animals, octopus blood is blue. This is because it contains the protein hemocyanin, filled with copper instead of iron as in human blood. This protein can efficiently transport oxygen molecules in the cold, low-oxygen conditions found under the sea.
How many hearts do squids have?
Squids also have three hearts. They are part of the cephalopod family alongside octopuses, cuttlefish and nautiluses. All cephalopods have three hearts and blue blood.
How many brains does an octopus have?
Octopuses have nine brains. Each of their eight arms contains its own small brain, allowing the arms to act independently and complete tasks efficiently. The central brain controls the nervous system.
Octopuses absorb information through their arms – their strong suckers help them smell, taste, move around and grab things.
How smart are octopuses?
Octopuses have as many neurons as dogs – around 500 million – and a larger nervous system than all other invertebrates. Two-thirds of these neurons are in their arms and the rest are in the brain.
These intelligent creatures use tools to their advantage and indicate the ability to learn by building dens and collecting items like rocks, shells and bottle caps, which they clean off with water spurts. They’ve been observed carrying venomous Portuguese man o’ war tentacles when hunting and use scare tactics to frighten and trick prey.
Octopuses are also keen escape artists and can adapt well to their surroundings. In this YouTube video, an octopus successfully navigates her way through a series of traps and mazes to reach a feast of raw shrimp:
Two aquariums observed octopuses who learned to turn off the lights by spraying water at light bulbs to short-circuit the power, according to Scientific American. Other aquariums noted that octopuses recognize keepers – one octopus squirted a staff member every time she walked by. Studies show octopuses will behave differently toward keepers they determine to be either “nice” or “mean.”
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This article originally appeared on USA TODAY: How many hearts does an octopus have? Inside the creature's anatomy
