Octopuses have three hearts and blue blood—and when they swim, two of those hearts stop beating. Because of that, swimming exhausts them, which is why they usually prefer crawling along the seafloor instead of swimming through open water.
Octopuses have taste receptors on their suckers. Each arm can “taste” whatever it touches, letting the octopus explore and decide if something is edible just by grabbing it. Their nervous system is so distributed that the arms can perform complex sensing and movement partly independently of the brain.
Octopuses routinely edit their own RNA after it’s made, changing how their proteins work without altering their DNA. This is unusual—most animals hardly do this at all. In octopuses, thousands of genes get edited this way, especially in the nervous system, which may help their neurons function better in cold ocean water. The trade‑off is that heavy RNA editing seems to limit how quickly their DNA can evolve, so octopuses may have traded long‑term evolutionary flexibility for short‑term neural adaptability.