What invertebrate has blue blood and multiple brains?
An octopus!
What does it mean for an octopus to have multiple brains?
Octopuses have a distributed nervous system, with nerve bundles in each arm in addition to a central brain in the head, for a total of nine brains. Up to two thirds of all of their nerves are in their tentacles, and the decentralized structure allows each arm to be responsible for its own coordination, potentially allowing for spontaneous reactions in different tentacles. Good for multitasking!
Why does an octopus have blue blood?
Just like humans have hemoglobin in our bloodstream to carry oxygen through our bodies, octopuses have the copper-based protein hemocyanin in their blood. Hemocyanin is well-adapted to circulation in very cold ocean environments, where some species of octopus dwell, and as the “cyan” in the name suggests, it causes the blood to turn blue.
What other strange properties does an octopus have?
Octopuses are unique in the makeup of their bodies, which have no bones, and few areas of chitin, a stiff substance that gives them some structure. Instead, their bodies are made up of mostly muscle, which enables them to squeeze through very small spaces. Check it out!
All species of octopus are actually venomous, but only the blue-ringed octopus has venom that is lethal to humans.
Octopuses can also camouflage themselves to hide from predators and aid their hunting, changing the color, pattern, and even texture of their skin. They have cells called chromatophores which can change color once the octopus senses a nearby predator, while tiny muscles change the texture. Watch it happen:
How are human activities impacting octopuses?
Because in most cases, the octopus is a solitary creature and it is found in wide areas of ocean, it is difficult for researchers to gauge the status of most octopus populations. However, they are susceptible to the pressures of overfishing, and it is an open question how climate change and the rise in ocean temperature and acidity will affect the octopus.
Its unique anatomy, capacity for camouflage, and remarkable intelligence make the octopus an astounding animal, and it’s no wonder that the octopus has long fascinated humans. These eight-legged creatures are amazing, and offer just one example of the strange organisms that roam our oceans. For an inspiring story about the life of one octopus and the man who bonded with her, check out the film My Octopus Teacher on Netflix. Other fantastic accounts of human-octopus bonding can be found in Sy Montgomery’s beautiful book The Soul of An Octopus, or in some of her many talks.