Octopuses have a relatively big brain just like other smart animals. But their highly complex nervous system evolved independently from vertebrates. Surprisingly, most of the neurons that do the computing for the brain are in the octopus’s arms. And that means they may have essentially nine brains, not one.
Scientists think it’s their long evolutionary history that explains their smarts. Cephalopods have been on earth for around 520 million years ago; the oldest known octopus fossil is about 330 million years old.
Investigations into the brains of octopuses found that they contain high levels of regulatory RNA molecules (microRNA), which could have helped them develop lots of different neurons and greater neuronal complexity. The scientists say“…the brains of cephalopods evolved greater complexity in the same way as vertebrate brains did – by using a lot more regulatory RNAs to control gene activity.”
Listen to a Podcast about octopus intelligence with author Sy Montgomery.
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