{"id":139170,"date":"2025-09-12T18:19:09","date_gmt":"2025-09-12T18:19:09","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/139170\/"},"modified":"2025-09-12T18:19:09","modified_gmt":"2025-09-12T18:19:09","slug":"octopuses-have-a-favorite-arm-for-each-task-science","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/139170\/","title":{"rendered":"Octopuses have a favorite arm for each task | Science"},"content":{"rendered":"

More than the vault, the real torture for children in gym class is having to perform coordination exercises: for example, moving one arm vertically while making a circular motion with the other. The human brain ends up getting confused. But octopuses can do a different thing with each of their eight arms or legs. A study published in Scientific Reports<\/a> also shows how they reserve certain limbs for specific tasks. The authors of the research conclude that, based on their results, \u201cthe octopus is a very tactile animal \u2013 it\u2019s more tactile than visual\u201d<\/p>\n

Marine biologists from the United States recorded 25 octopuses (three of them in the Vigo estuary), from three different species and six ecosystems across Europe and America. They documented over 4,000 arm movements, which allowed them to create what they call an ethogram \u2014 a catalog of the species\u2019 behaviors or actions. They identified 15 behaviors (ranging from hiding to mating) and 12 movements (from lifting to reaching) of their eight arms, each of which can perform four basic deformations: elongating, contracting, stretching, or twisting. Adding to this complexity, each deformation can occur in the part of the arm closest to the head (proximal), the middle, or the tip (distal).<\/p>\n

By analyzing all these combinations, the researchers confirmed the extreme dexterity of these cephalopods<\/a>. One key finding is that each of the eight arms is capable of performing all types of actions; however, they also detected a clear pattern of task distribution. For example, the front limbs are mainly used for movements that help explore the environment, while the rear limbs are used for actions related to locomotion. <\/p>\n

A specific detail points to the proactive nature of this unusual animal: the two front arms are used 64% of the time, while the two rear arms are used only 36% of the time. Despite this differentiation between front and rear limbs, octopuses are neither right- nor left-handed. The scientists found no lateralization, with left and right limbs performing almost the same number of actions (51% versus 49%, respectively).<\/p>\n

\"LosOctopuses have four sets of muscles surrounding an axial nerve in each arm and thousands of neurons in each of the hundred suckers on each of their eight limbs. The image shows a specimen recorded in the U.S. Caribbean.
\nRoger Hanlon<\/p>\n

\u201cObserving them in the wild, we saw octopuses use different combinations of arm actions,\u201d says Chelsea O. Bennice, a biologist at Florida Atlantic University\u2019s Marine Laboratory, in a press release. \u201cSometimes [they use] just one arm for tasks like grabbing food, and other times multiple arms working together for behaviors like crawling or launching a parachute attack \u2014 a hunting technique<\/a> they use to catch prey.\u201d <\/p>\n

No significant differences were found \u2014 beyond adaptations to each environment \u2014 in the behaviors observed across the six ecosystems, ranging from sandy beaches to reefs, nor in the movements of the three recorded species.<\/p>\n

Combining all possibilities, the researchers documented 6,781 arm deformations. Each arm has a muscular configuration that, when all its possibilities are considered, explains the fascination many biologists have with this animal: the eight arms contain four sets of muscles. Some are transverse, others run longitudinally from the base to the tip, a third group is oblique along the length of the arm, and they also have circular muscles, like rings. The four sets surround an axial nerve that receives sensory input and distributes instructions to each part of the arm. The researchers observed that octopuses can deform each of the three segments (proximal, middle, and distal) of an arm differently and independently. While one arm stretches to explore, its tip twisting along its axis, others bend to lift the body, flexing a segment to remain upright.<\/p>\n

And one must not forget the suckers. \u201cEach sucker is a chemo-tactile genius, the equivalent of the human nose, lips and tongue all wrapped into one,\u201d says Roger Hanlon, a researcher at the Marine Biology Laboratory and senior author of the study, in a press release. There are about 100 suckers on each arm, roughly 800 in total, and each contains thousands of distinct neurons. It has been estimated that an octopus has roughly 500 million neurons<\/a>, far fewer than the nearly 100 billion in humans. But the key is in their distribution. Most human neurons are concentrated in the brain, whereas in the cephalopod, they are primarily in the arms and suckers.<\/p>\n

Antonio Figueras, a professor at the Institute of Marine Research (IIM-CSIC), points out that \u201coctopuses have seven times more neurons in the periphery than in the center, whereas in humans, the ratio is reversed, with five to six times more in the central nervous system than in the rest of the body.\u201d <\/p>\n

Three years ago, it was discovered that each arm has nerve connections with its two neighboring arms<\/a>, confirming that this is one of the most decentralized nervous systems known. In an article published in The Conversation, the Spanish scientist described the octopus as an animal whose brain is distributed throughout its body. For Figueras, who did not participate in the current study, \u201ccephalopods are evolution\u2019s aliens, having developed intelligence along a parallel, alternative path to that of humans.\u201d<\/p>\n

The U.S. Naval Research Office, part of the country\u2019s Navy, partially funded the research with the idea of applying it to the development of robotic arms that are both highly flexible and sensory-capable. After a submarine sinks or a building collapses, Hanlon asks: \u201cHow do you deliver a drug or a phone or water to someone who\u2019s [trapped] down there? You need some snaky little arm with high flexibility that cannot only get down there but can do something useful when it arrives,\u201d he concludes.<\/p>\n

Sign up for our weekly newsletter <\/a>to get more English-language news coverage from EL PA\u00cdS USA Edition<\/p>\n","protected":false},"excerpt":{"rendered":"More than the vault, the real torture for children in gym class is having to perform coordination exercises:…\n","protected":false},"author":2,"featured_media":139171,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[49,48,75094,66,323],"class_list":{"0":"post-139170","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-wildlife","8":"tag-ca","9":"tag-canada","10":"tag-fauna","11":"tag-science","12":"tag-wildlife"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/139170","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=139170"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/139170\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/139171"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=139170"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=139170"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=139170"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}