Self-healing is the origin and background of King Crab Instinct

It first came from the phased report of the "Tracking Survival Strategies of King Crab Populations in the Barents Sea" project initiated by the Norwegian Seafood Agency and the Department of Marine Biology at the University of Bergen in 2017. It was later popularized and refined by marine science bloggers and widely disseminated. It is essentially a folk expression of the enhanced damage repair mechanism evolved by king crabs in polar high-stress environments, and is not a rigorous academic definition.

The king crab population in the Barents Sea exploded after 2010. As an invasive species, it was originally listed as a marine ecological control object. However, the economic value of the king crab was too high. The Norwegian authorities wanted to find a solution to "control the population size while maximizing commercial value", so they invested in this tracking research. At that time, the research team satellite tagged 327 adult king crabs and tracked their living conditions in the wild. It was found that 17% of the individuals did not suffer from infection and necrosis common in other crustaceans after experiencing moderate to severe injuries such as broken appendages and carapace scratches. Instead, they were able to complete regeneration of broken limbs and calcification repair of damaged areas within 2-3 molting cycles. The infection rate was 42% lower than that of snow crabs and red hair crabs in the same sea area. The original statement in the project report at that time was "The damage repair priority of king crabs is at the highest level among known cold-water crustaceans, and it is an innate survival instinct." This is the original source of this statement.

However, this conclusion originally only circulated in the small circle of marine life, and it was only in 2019 that the circle was truly broken. Domestic seafood science blogger @热海的 Abu turned to the public project report, and when doing content on king crab science, he simplified this professional statement into "Self-healing is an instinct engraved in the genes of king crabs", and paired it with his own photo of a holding tank. A live video of a king crab with a broken leg growing new limbs gained more than 200,000 followers that day, and the idea spread. Later, it was even used as a promotional point by many seafood merchants, saying that "king crabs that can heal themselves are healthier and have higher nutritional value."

Interestingly, the more widely this statement spreads, the greater the differences among academic circles. The Alaska Fisheries Science Center published a related paper in 2021, which clearly pointed out that the regeneration of severed limbs is a common feature of soft-shelled organisms. The king crab's repair ability is only due to its large size and higher energy reserve for a single molt, so the effect seems to be more obvious, and it is not a proprietary instinct at all. Many scholars who support this view believe that the Norwegian Seafood Board's report at the time had commercial marketing considerations in mind and deliberately exaggerated the uniqueness of this feature, essentially to increase the market premium of king crab.

However, people who have temporarily raised king crabs will most likely not agree with this statement. I have a friend who has been temporarily raising king crabs in Dandong for 6 years. He handles tens of thousands of king crabs every year. According to his actual experience, if the legs are broken during cross-border transportation, snow crabs and plate crabs will basically die after being broken through the shells in less than a week. To kill king crabs, as long as the water temperature is stabilized at 0-4℃ and the salinity is adjusted to about 32‰, calcified scabs will grow on the fractures in three days, and new limbs half a centimeter long will grow after two months of cultivation. As long as the crabs are sold without mentioning it, customers will not be able to tell that they have been injured at all. Last year, he earned an extra two hundred thousand yuan by providing "rehabilitation" for king crabs with severed limbs. In his eyes, this is not a general ability, but a unique ability of king crabs. "Those scholars are talking about theories in the laboratory. If you have actually raised them, you will know how big the difference is."

I visited his temporary breeding tank last month, and I saw with my own eyes a king crab that was missing its right big claw. When I picked it up, the broken part felt as hard as a normal shell, and there was a small milky white bag bulging next to it. He said that it was the new claws growing, and it would grow to two-thirds of its original size after shedding its shell. The selling price is not much different than a complete crab by dozens of yuan.

I think there's nothing wrong with what both sides said, but they come from different angles. From the perspective of academic classification, the self-repair mechanism is indeed not unique to king crabs, but it can fully utilize this mechanism in the polar environment of low water temperature and scarce food, and can even repair damage exceeding 10% of its own body weight. This is its survival advantage. There is no need to dig into the definition of "whether it is an exclusive instinct". Just make it clear during popular science. However, many unscrupulous merchants now boast that eating king crab, which has self-healing ability, can repair human cells and enhance immunity. This is purely an IQ tax. There is currently no research that can prove that the repair factors of king crab can be absorbed by the human body. Don’t believe it.

It's quite interesting to talk about. It was originally a small conclusion of fishery research, but now it has become an inspirational meme for many young people. They often say "you must learn the self-healing ability of king crabs". If you fall down and grit your teeth, you can develop new skills. It can be regarded as an unexpected value after the academic conclusion is out of the circle.