Designed for Survival: The Extreme Biology of Octopuses

Istock PETA. (n.d.). Octopus eight-armed Einsteins of the deep [Image]. PETA. https://www.peta.org/features/octopuses-eight-armed-einsteins-of-the-deep/

What if the closest thing to an alien has been hiding in our oceans all along? A creature with three beating hearts, blue coloured blood, and arms that can think, taste and move all on its own. This isn’t science fiction. It’s the octopus, one of the most extraordinary creatures that roam our Earth (Smithsonian Ocean, 2023). For years, stories of octopus intelligence have captured public attention. Activities such as opening latches, escaping tanks and solving puzzles are all due to their entire biology being built to survive in the harshest marine conditions on the planet (PETA 2014). An octopus is a type of cephalopod which means “head foot” in Greek, in relation to the way it has 8 or more arms connected to its head. Octopuses are organisms that reveal a blueprint of life completely different from our own, so scientists now study these characteristics to understand how octopuses thrive but also to make advancements in medicine and robotics inspired by their abilities (Zarrella et al., 2015).

Blue Blood and Three Hearts 

Their blood is dark and inky, a peculiar trait that surprisingly is one of the keys to its survival. Unlike the red human blood, which contains haemoglobin, the octopus has blue blood because it contains hemocyanin, a copper-based protein that transports oxygen. This characteristic is vital to the survival of octopuses in deep ocean waters, as it helps them transport oxygen despite the cold temperatures and low-oxygen environments. When the blood is oxygenated, the copper gives it the blue hue that octopuses are famous for (Porter, M, 2025). To support this system, octopuses also possess three hearts. Two of them are responsible for pumping blood through the gills, and one pumps oxygenated blood through the rest of the body (Porter, M, 2025). Their unique cardiovascular system allows scientists to gain valuable insights into how the transport of oxygen works under extreme environments, helping us understand much more about marine physiology and medical innovations.

Distributed Intelligence: A Brain in Every Arm

A reason for its three hearts is due to another unusual feature of an octopus’s anatomy: nine brains. Each of its eight tentacles contains a mini brain, known as the ganglia, which allows each arm to operate with a surprising level of independence. This decentralized nervous system allows an individual arm to taste, touch, and move on its own (Maxwell, A. 2022). These organisms are exceptionally intelligent, and due to this extensive nervous system, three hearts are required. Soft robotic designs have been developed from understanding how octopus arms coordinate complex movements. Medical tools capable of navigating small spaces in the human body and flexible underwater drones are examples of this. Future AI systems may also be influenced by the way the octopus's anatomy processes information, not one sole processor but multiple (Duan et al., 2025). 

Shape-shifting Masters

Chameleons are famous for blending in, but what if the real master of camouflage isn’t on land at all? Another alien-like ability that sets octopuses apart is camouflaging in the blink of an eye. They can change their skin tone, texture, and even the pattern of their skin. This is possible due to thousands of specialized colour-changing cells—chromatophores, iridophores, and leucophores—to reflect different wavelengths of light (Hanlon, 2007). Octopuses do this to blend in with their surroundings and hide from predators. They change not only their skin color, but also their texture to fit in with the surrounding corals, rocks, and other objects. Octopus papillae allow them to instantly change their skin’s 3D texture to perfectly mimic their surroundings (Meyer, 2019). Engineers studying this adaptive camouflage are already developing flexible materials that automatically change color and texture, including military cloaking fabrics (Chandler MIT, 2014). 

Octopus helping masters disguise [Photograph]. (n.d.). CreateDigital. https://createdigital.org.au/octopus-helping-masters-disguise/

In the end, the octopus is far more than a strange marine creature: it is evidence for some of the most advanced biological anatomies on Earth. From blue blood for survival in oxygen-poor waters, to arms that can think independently, to skin capable of instant camouflage, every part of an octopus pushes boundaries of what we consider “normal” life. These adaptations don’t just make octopuses seem alien but offer humans opportunities for future innovation. Engineers are designing robots inspired by octopus arms, doctors are exploring new tools influenced by their flexibility and scientists are developing shape-shifting surfaces that mimic their skin. In studying the octopus, we aren’t just learning about an animal - we’re discovering biological breakthroughs for the future of technology and medicine.  

References 

5 Times Octopuses Made Headlines. (2014, October 7). https://www.peta.org/features/5-times-octopuses-made-headlines/

Smithsonian Ocean. (2023). Octopus. Smithsonian Institution.  https://ocean.si.edu/ocean-life/invertebrates/octopuses-squids-and-relatives

Zarrella, I., Ponte, G., Baldascino, E., & Fiorito, G. (2015). Learning and memory in Octopus vulgaris: a case of biological plasticity. Current Opinion in Neurobiology, 35, 74–79. https://doi.org/10.1016/j.conb.2015.06.012

Porter, M. (2025, May 24). Did You Know Octopus Have Three Hearts And Blue Blood? These Magnificent Marine Mollusks Are Being Exploited And Need Our Help - Animal Save Movement. Animal Save Movement. https://thesavemovement.org/did-you-know-octopus-have-three-hearts-and-blue-blood-these-magnificent-marine-mollusks-are-being-exploited-and-need-our-help/

Maxwell, A. (2022, October 5). Now. Powered by Northrop Grumman - Now. Powered by Northrop Grumman. Northrop Grumman. https://now.northropgrumman.com/nine-brains-three-hearts-and-other-octopus-anatomy-facts

Duan, J., Lei, Y., Fang, J., Qi, Q., Zhan, Z., & Wu, Y. (2025). Learning from Octopuses: Cutting-Edge Developments and Future Directions. Biomimetics, 10(4), 224. https://doi.org/10.3390/biomimetics10040224

Fox Meyer. (2019, March 29). How Octopuses and Squids Change Color. Si.edu. https://ocean.si.edu/ocean-life/invertebrates/how-octopuses-and-squids-change-color

Chandler, D. L. (2014, September 16). How to hide like an octopus. MIT News | Massachusetts Institute of Technology. https://news.mit.edu/2014/material-changes-color-texture-octopus-0916