These animals can experience distress. They are also able to self-administer analgesics or anesthetics when they get injured.
According to researchers, being sentient is defined as the ability to have feelings and experience sensations of pain, pleasure, hunger, thirst, heat, joy, comfort, and excitement (Photo: Getty Images)
Octopus, lobsters, and crabs –a group which you have surely seen on restaurant menus– have been declared sentient beings with rights by a study from the United Kingdom.
This study, undertaken by the London School of Economics and Political Science (LSE), consisted of tracking behavioral and cognitive signatures of sentience through eight markers.
The results of the review show that these organisms are capable of feeling pain and suffering.
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The meticulous study of the stomatogastric neurons of lobsters and crabs has put human brain research on a safe path. (Photo: iStock)
For many years, sentience was attributed to the neocortex, a specific structure in the cerebral cortex consisting of six layers of abundant and well-organized neurons.
There is no evidence of an organized neocortex like ours in invertebrate animals such as octopuses, lobsters, and crabs.
However, “we cannot conclude that sentience is absent in an invertebrate simply because its brain is differently organised from a vertebrate brain,” explained the authors of the LSE’s Review of the Evidence of Sentience in Cephalopod Molluscs and Decapod Crustaceans.
An octopus (cephalopod) has 500 million neurons, almost the same as a dog (530 million), but most of these cells are not in its brain. More than two thirds of its neurons are found in its tentacles in the form of mini brains.
They have the ability to learn, solve problems and puzzles, distinguish between present, past and future, and possibly dream.
Lobsters and crabs (decapods) have very small brains, but also have a network of 30 stomatogastric neurons which send signals to each other and synchronize rhythmic activity.
There are regions of their brains that are specifically linked to functions such as learning and memory. The study of their stomatogastric cells has put human brain research on a safe path, according to Brandeis University neuroscientist Eve Marder.
Invertebrate brains are very different from those of humans because they are separated by more than 500 million years of evolution.
Octopuses have 500 million neurons, two-thirds of which are found in their tentacles. (Photo: Getty Images)
So, what is the evidence for these species being sentient? The UK team created a set of criteria to track the behavioral and cognitive signatures of sentience in these animals.
This team from the London School of Economics and Political Science (LSE) identified eight factors, which can be summarized as:
Octopuses tested positive for all indicators, while crabs and lobsters tested positive for five.
Furthermore, the researchers uncovered incredible information within these signatures of sentience.
Decapods can experience pain, distress, and injury. They have specific regions of the brain to do so, which gather information from pain receptors in different parts of the body.
These animals also engage in self-protective behavior, such as taking care of their wounds and grooming themselves.
Cephalopods possess all of the above characteristics. The scientists also observed that they self-administer analgesics or anesthetics when they are injured.
During a stressful situation such as an injury, octopuses look for a safe place to access these pain reducing substances. They are even capable of preferring these compounds over food.
The study concluded that these are sentient animals, and the United Kingdom has taken important steps to protect them, such as adding them to a list of sentient beings that must be protected by new animal welfare laws.
This bill has not yet been approved as legislation, but a committee on animal sentiment will be created to issue reports on government decisions regarding the welfare of the sentient animals.
