The octopus is a creature with three hearts, blue blood, and a donut-shaped brain. Yet, there are still more surprising facts about it. Octopuses are known for their intelligence; they keep surprising us with their incredible abilities and behaviors. Let us discuss some of them.
1. Multiple Brains
You probably know that an octopus has eight arms, but are you aware that each of them has its own brain? While studying the collection of cephalopods at the Natural History Museum in Britain in 2019, John Ablett found that these brains allow the octopus to control its arms more quickly and efficiently, and enable it to move each arm independently and in all directions.
2. Sharp Intelligence
Scientists measure an animal’s intelligence by calculating the ratio of brain size to total body size: the higher the ratio, the more intelligent the creature is. Octopuses have the highest ratio of all. The octopus body contains 500 million nerve cells, with two-thirds located in its arms and one-third in its donut-shaped brain circulating the esophagus.
Octopuses have shown intelligence in various experiments, solving mazes, and completing difficult tasks to obtain food rewards. They have also managed to maneuver their bodies into and out of bottles skillfully—check this photo.
There are plenty of amusing stories about the octopus behaviours. I have once read a story about a laboratory where fish kept disappearing from the tanks. Upon installing a camera, researchers discovered that an octopus used to get out from its tank at night, open the lids of nearby tanks, feed on the fish, then carefully replace the lids and return to its own tank without leaving a trace.
3. Using Tools Skillfully
The use of tools is not common in the animal kingdom; it is limited to some primates, dolphins, and certain birds such as crows and parrots. Yet, octopuses collect stones, broken bottles, bottle caps, and shells to build shelters that protect them and their offspring.
4. Ability to Recognize Individuals
The octopus has a large optical cavity that gives it wide vision and sharp eyesight, enabling it to recognize human faces. Scientific American published a story from the University of Otago in New Zealand, where a captivated octopus showed dislike toward a staff member. Each time that person passed by the tank, the octopus would spray them with water.
Biologists at the Seattle Aquarium conducted an experiment to test the giant Pacific octopus ability to recognize individuals. For two weeks, one person regularly fed a group of octopuses, while another touched them with a rough stick. By the end of the experiment, the octopuses behaved differently toward the “kind” keeper and the “mean” one, demonstrating their ability to distinguish between them, even though both wore the same uniform.
5. The Self-Sacrificing Mother Phenomenon
Life is not easy, even for octopus mothers who sacrifice their lives for their young. In some species of octopus, females show parental care by guarding their eggs, protecting them from predators, and passing water over them to provide oxygen. This behavior continues until the eggs hatch. In some shallow-water species, this behavior may continue for about three months after the hatch. Yet, some octopuses take parental care to the extreme.
The title “Ideal Mother of the Year” goes to the deep-sea octopus Graneledone boreopacifica. A female octopus was observed brooding its eggs for 53 months—nearly four and a half years—marking the longest known brooding period of any animal. During 18 dives in the depths of Monterey Canyon, California, researchers never saw the female leave her eggs or eat anything, not even the crabs or shrimps that wandered nearby. Instead, it lost weight, its skin became loose and pale, and its eyes turned cloudy. It seemed to be awaiting an inevitable death.
6. Building Colonies and Camouflaging
Octopuses have thousands of specialized cells in their skin known as chromatophores, which help them change color instantly. They also have small areas of skin that can expand or contract, known as papillae, which allows them to quickly change their skin texture to match its surroundings.
While octopuses are generally considered non-sociable creatures, scientists made a surprising discovery in Jervis Bay, Australia, in 2012. The species Octopus tetricus, which was thought to prefer solitude, was found living in crowded colonies. Within these colonies, built from rocky outcrops and piles of leftover shells, these octopuses mate and fight over limited hiding spaces.
Mimic Octopus - Scientific Figure on ResearchGate.
Finally, why is the octopus blood blue?
Octopus blood contains a blue-colored protein known as hemocyanin, which is rich in copper, unlike hemoglobin, which is rich in iron. Hemocyanin is more efficient at transporting oxygen molecules in cold, low-oxygen environments, making it ideal for marine life. When the creature dies and its blood does not carry oxygen anymore, it loses its blue color and turns clear.
References
doi.org/10.1371/journal.pone.0103437
doi.org/10.1016/j.cub.2009.10.052
doi.org/10.1111/j.1096-3642.1977.tb00026.x
doi.org/10.1016/j.cub.2011.01.052
doi.org/10.1098/rstb.2013.0052
doi.org/10.1080/10888705.2010.483892
doi.org/10.1016/j.cub.2015.12.033
Cover image source: www.flickr.com