We named her Squirt – not because she was the smallest of the 16 cuttlefish in the pool, but because she was likely to get wet if anyone dared move her to a separate tank to study her. Squirt’s aim was extremely accurate.
As a comparative psychologist, I am accustomed to attacking my experimental subjects. I have been stung by bees, stung by crayfish and pounced upon by angry pigeons. But, somehow, it felt different with Squirt. When he looked at us with his W-shaped pupils, it seemed as if he was plotting against us.
Of course, I am anthropomorphic. Science does not yet have the tools to confirm whether cuttlefish have emotional states, or whether they are capable of conscious experience, let alone sinister plots. But there’s undoubtedly something special about cephalopods – the class of sea-dwelling invertebrates that includes cuttlefish, squid and octopus.
As researchers learn more about the cognitive skills of cephalopods, calls have arisen to better deal with their intelligence levels. California and Washington state both approved bans on octopus farming in 2024. Hawaii is considering similar action, and has introduced a ban on octopus farming or the importation of farmed octopus meat in Congress. A planned octopus farm in Spain’s Canary Islands is attracting opposition from scientists and animal welfare advocates.
Critics cite several arguments against raising octopus for food, including the potential release of waste, antibiotics or pathogens from aquaculture facilities. But as a psychologist, I see intelligence as the most interesting part of the equation. How Smart Are Cephalopods Really? After all, it’s legal to raise chickens and cows. Is the octopus smarter than, say, a turkey?
a large, diverse group
Cephalopods are a broad class of mollusks that includes the coleopterans – cuttlefish, octopus and squid – as well as the chambered nautiluses. Colloids range in size from adult squid to only a few millimeters long (idiosyncratic) the largest living invertebrate, the giant squid (Architeuthis) and giant squid (Mesonychoteuthis) which can exceed 40 feet in length and weigh more than 1,000 pounds.
Some of these species live alone in the almost formless darkness of the deep sea; Others live on socially active, sunny coral reefs. Many are skilled hunters, but some feed passively on floating debris. Because of this enormous diversity, cephalopod brains and behavior also vary greatly in size and complexity.
Much of what is known about cephalopod cognition comes from intensive study of only a few species. When considering the welfare of a specified species of captive octopus, it is important to exercise caution in using data collected from a distant evolutionary relative.
Can we even measure alien intelligence?
Intelligence is extremely difficult to define and measure, even in humans. The challenge increases exponentially in studying animals with sensory, motor, and problem-solving skills that differ significantly from ours.
Historically, researchers have focused on whether animals think like humans, ignoring the abilities animals have that humans do not have. To avoid this problem, scientists have attempted to find more objective measures of cognitive abilities.
One alternative is the relative measurement of brain and body size. The best studied species of octopus, octopus vulgarishas approximately 500 million neurons; It is relatively large due to its small body size and is similar to a starling, rabbit or turkey.
More precise measures might include the size, neuron count, or surface area of specific brain structures known to be important for learning. Although this is useful for mammals, the octopus’s nervous system is built completely differently.
more than half the neurons octopus vulgarisAbout 300 million are not in the brain at all, but distributed in “mini-brains” or ganglia in the arms. Within the central brain, most of the remaining neurons are dedicated to visual processing, with less than a quarter of its neurons left for other processes such as learning and memory.
In other species of octopus, the general structure is similar, but the complexity varies. Wrinkles and folds in the brain increase its surface area and can increase neural connections and communication. Some species of octopus, particularly those living in rocky habitats, have more wrinkled brains than deep-sea species, suggesting that these species may have higher levels of intelligence.
In search of a better breakfast
Because brain structure is not an infallible measure of intelligence, behavioral tests can provide better evidence. One of the highly complex behaviors that many cephalopods show is visual camouflage. They can open and close small sacs just beneath their skin that contain colored pigments and reflectors, which reveal specific colors. octopus vulgaris There are up to 150,000 chromatophores, or pigment sacs, in one square inch of skin.
Like many cephalopods, the common cuttlefish (sepia officinalis) are considered colorblind. But it can use its excellent vision to produce a swirling series of patterns on its body as camouflage. Australian giant cuttlefish, sepia apamaUses its chromatophores to communicate, creating patterns that attract mates and warn off attackers. This ability can also be useful for hunting; Many cephalopods are ambush predators that blend into the background or even lure their prey.
However, the hallmarks of intelligent behavior are learning and memory – and there is plenty of evidence that some octopuses and cuttlefish learn in a way that is equivalent to learning in vertebrates. Common Cuttlefish (sepia officinalis), as well as the common octopus (octopus vulgaris) and day octopus (octopus cyanea), can all make simple associations, such as learning which image on the screen predicts that food will appear.
Some cephalopods may be capable of more complex forms of learning, such as reversal learning – learning to flexibly adjust behavior when different stimuli signal a reward. They may also be able to stop impulsive reactions. In a 2021 study that gave common cuttlefish a choice between the less desirable but immediate snack of crab and the preferred treat of live shrimp after a delay, many cuttlefish chose to wait for the shrimp.
A new frontier for animal welfare
Considering what is known about their brain structures, sensory systems, and learning abilities, it appears that cephalopods as a group may be similar in intelligence to vertebrates as a group. Since many societies have animal welfare standards for rats, mice, chickens, and other vertebrates, logic would suggest that the same is the case for regulations enforcing the humane treatment of cephalopods.
Such regulations generally specify that when a species is kept in captivity, its housing conditions must support the animal’s welfare and natural behavior. This approach has led some US states to outlaw confined cages for egg-laying hens and cages that are too narrow for pregnant pigs to roam around in.
Animal welfare regulations say little about invertebrates, but guidelines for the care and use of captive cephalopods have begun to emerge in the last decade. In 2010, the European Union required ethical issues to be considered when using cephalopods for research. And in 2015, AAALAC International, an international accreditation organization for ethical animal research, and the Federation of European Laboratory Animal Science Associations promoted guidelines for the care and use of cephalopods in research. The US National Institutes of Health is currently considering similar guidelines.
The “alien” brains of octopuses and their relatives are fascinating, not only because they provide a mirror through which we can consider more familiar forms of intelligence. To decide which species deserve ethical consideration, it is necessary to select criteria such as neuron count or learning ability to inform those choices.
Once these criteria have been determined, it would also be good to consider how they apply to rodents, birds, and fishes that play more familiar roles in our lives.
,Author: Rachel Blazer, Professor of Neuroscience, Cognition and Behavior, University of San Diego)
,disclosure statement: Rachel Blazer does not work for, consult, hold shares in, or receive funding from any company or organization that would benefit from this article, and has no relevant affiliations beyond her academic appointment. not disclosed)
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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