Do you think eating crabs is troublesome? We can find a tool octopus

When the crab is served, the navel is first opened, and then the shell is peeled. In an instant, it is as if the universe was created, and the golden crab roe is exposed to the eyes of the gourmets. Then, use chopsticks or a knife and fork to pick out the rich crab roe, and you can enjoy it to your heart's content. However, if you want to enjoy the rest of the crab meat, you have to crack the hard shell, peel the crab body, and penetrate the crab claws to taste the sweetness of the crab meat.

Men of letters call this "slow work and fine production", while ordinary people use another appropriate word to describe it - "hard work".

When people who don't know how to eat crabs eat crabs, it's better to say "crabs eat people" rather than "people eat crabs". A stranger eating crabs is like a tiger eating a hedgehog. He doesn't know how to start eating. In the end, he bites the crab with the shell in one bite, picks out the meat with his tongue, and spits out the shell and meat. After this, he barely eats half of the crab meat. Even for a skilled crab eater, it takes dozens of minutes to pick out every bit of meat from the crab shell, and by then the crab is already cold and no longer delicious.

Crabs are delicious, but difficult to handle

(Image source: How to Eat Crabs: 10 Steps (with Pictures) – wikiHow)

Is there any simple way to let us eat the whole crab meat? To solve this big problem, maybe you need a tool person, no, a tool octopus.

The deliciousness of crabs is irresistible. The first time you eat crabs, you are embarrassed. The second time, you are hesitant. The third and fourth times, you are reluctant. The fifth and sixth times, you become more proficient. The seventh and eighth times, you have some experience. After eating a few more times, you can be called an expert in eating crabs. Through repeated practice, human beings' crab-eating skills can be increasingly sophisticated. The octopus, which has been eating crabs for more than 100 million years, has reached the pinnacle of crab-eating skills. Its crab-eating skills are written into its genes, and it knows it by nature: it can subdue the crab in 30 seconds, separate it in 5 minutes, and eat the crab completely in half an hour, leaving only a complete crab shell.

In this case, if we can get the octopus to help, we can enjoy a one-stop crab-eating service from "catching to detaching the shell".

Octopus eating crabs

(Image source: Smithsonian Ocean - Smithsonian Institution)

Part 1

Afraid of being pinched by crab claws? Let the octopus take care of this fear for you

Getting the octopus to help you only takes two steps. The first step is to put the crab into the same fish tank as the octopus.

After finding the crab, the octopus will quickly get out of its nest and rise into the water. After determining the target location, the octopus will swing its head, dive down by spraying water, grab the crab with its tentacles, and wrap it in the net formed by the connecting membrane between the tentacles. At this time, the crab can still resist strongly, but it is in vain.

The octopus then points the front of the crab's shell toward its mouth and penetrates weak areas of the exoskeleton, such as the eyes, weak points in the shell, and the fragile membrane at the connection between the body and joints, and bites a small hole with its mouth; then, the key to helping comes - the octopus inserts the posterior salivary gland duct into the hole in the shell and injects a complex solution including cardiotonic drugs, toxin complexes and specific hydrolases into the crab's body, directly hitting the blood sinuses behind the eyes and the central nervous system, paralyzing the crab within tens of seconds.

The octopus holds the crab's head toward its mouth, makes a hole, and injects the venom.

(Image source: TripAdvisor)

Even though the crab's carapace is too thick to penetrate, the octopus is not intimidated. It uses a catheter to inject extracts from the posterior salivary glands into the crab's gills. The gills provide an entry point with a large membrane for substances to enter the vascular system, allowing the toxins to enter the bloodstream through breathing. This process is very fast, and in less than a minute, the crab is paralyzed and will soon die.

The crabs, which were injected with octopus venom, have their legs and feet stretched out, indicating that they are paralyzed

(Image source: NiTE Flight Photo Graphics)

Part 2

Is it troublesome to cut meat? Let the octopus help you

The second step is just as simple - just take the crab out of the fish tank. Once the crab loses its ability to resist, the tool octopus's mission is over and the crab can be taken out from under the octopus.

Although the tool octopus has completed its work and "happily" returned to the fish tank, the process of helping us deal with the crabs is still ongoing.

The crabs that we just "rescued" from the octopus's jaws seemed to be no different except that they were paralyzed, but after a few minutes, something amazing happened: the compound fluid injected into the crabs by the octopus contained not only a toxin complex, but also a cardiotonic and a specific hydrolase, which can work outside the octopus' body. Among them, the cardiotonic is a high concentration of octopamine secreted by the octopus's posterior salivary glands, which is an analogue of mammalian norepinephrine and can increase the frequency and intensity of the crabs' heartbeats, allowing their hearts to continue beating for several hours after the body is paralyzed, and continue to distribute the injected hydrolase through the blood circulation.

The key to octopus eating crabs is the specific hydrolytic enzymes that can break down the muscles and exoskeleton attachments, separating the crab's internal soft body from the shell. The continuous heartbeat provided by the cardiotonic drug allows the hydrolytic enzymes to spread throughout the crab's body and ensure that the muscle and shell attachment structures are broken throughout the body, which is the so-called "shell-meat separation."

The "shell-meat separation" caused by the octopus is like a crab shedding its shell - the soft body comes out of the shell intact.

(Photo credit: NY HARBOR NATURE)

After a while, the crab shell is completely separated from any internal tissue. Just gently open the fragile carapace and navel connection, and the crab body will slide out from the connection between the abdomen and back like shedding a shell. At this time, the specificity of the hydrolase is highlighted - the enzyme will not act on any other crab tissue. The crab body is wrapped in the original membrane, and the delicious crab roe, crab meat and internal organs remain in place, original flavor.

In addition, the carapace of the crab legs can be easily separated at the joints, and the plump crab meat in the claws can be cleanly pulled out like meat strips. The crab meat is still wrapped in the membrane, firm and not loose, chewy and not rotten. The only difference from fresh crabs is that the shells are removed. Moreover, the crabs separated from the shells and meat will not die immediately, but will continue to survive for several hours under the effect of the cardiac stimulant, which is enough for Hema Fresh to deliver to your home.

The crabs treated by the octopus are like soft-shell crabs - everything except the shell is edible.

(Image source: Gallant Ocean Group)

After this precise and efficient processing, the octopus can enjoy large pieces of pure crab meat, and the remains of the crab eaten clean will be separated into many components and discarded outside the hole. For humans, there is only one more step to do - steam the shelled crab.

The ancestral heating technique comes in handy here: after steaming, all substances in the compound liquid that the octopus uses to treat the crab lose their toxicity and are no different from ordinary proteins, so there is no need to worry. Even if it is not processed, there will be no big problem: the octopus's venom is very specialized for crustaceans, and most octopus bites have no effect on humans, not to mention indirect consumption through crabs.

Soft-shell crabs can be fried, roasted, or deep-fried because they have no shells and can be eaten directly no matter how they are cooked.

(Image source: Epicurious)

Although using octopus to process crabs is a good method, humans have not yet accurately analyzed the composition of octopus hydrolases, so it is difficult to use this method to process crabs in large quantities, and only a few people can enjoy it. However, the "shell-meat separation" method of eating octopus has allowed us to find another alternative method: let the crabs take off their shells themselves.

At present, in actual production, humans can treat crabs with natural molting hormones, and then soak them in calcium hydroxide solution to provide calcium for crabs to molt; when the crabs molt, they are immediately frozen or cooked before the shell hardens. At this time, the hardness of the crab shell is only one-third of the normal hardness, and it can be eaten like fried shrimp after a little frying.

In Spain and Venice, deep-fried soft-shell crabs are a local delicacy. In Japan, soft-shell crabs are used to make sushi. The giant North Pacific octopus, which also lives in Japan, will suck the captured crabs onto the suction cups and carry them with them. Whenever they are hungry, they will eat a box of takeout. Faced with these cunning enemies that can ignore the hard shells, the crabs have no ability to resist and can only surrender. There is no way, who makes them too delicious...

References:

[1]Grisley, MS; Boyle, PR; Pierce, GJ; Key, LN (1999). Factors affecting prey handling in lesser octopus (Eledone cirrhosa) feeding on crabs (Carcinus maenas). Journal of the Marine Biological Association of the UK, 79(6), 1085–1090.

[2]WODINSKY, JEROME (1971). Movement as a Necessary Stimulus of Octopus Predation. , 229(5285), 493–494.

[3]Amodio P, Andrews P, Salemme M, et al. The use of artificial crabs for testing predatory behavior and health in the octopus[J]. ALTEX-Alternatives to animal experimentation, 2014, 31(4): 494-499.

[4]Grisley MS, Boyle PR, Key L N. Eye puncture as a route of entry for saliva during predation on crabs by the octopus Eledone cirrhosa (Lamarck)[J]. Journal of Experimental Marine Biology and Ecology, 1996, 202(2): 225-237.

[5]Wells MJ, Wells J. Observations on the feeding, growth rate and habits of newly settled Octopus cyanea[J]. Journal of Zoology, 1970, 161(1): 65-74.

[6]Ghiretti F. Cephalotoxin: the crab-paralysing agent of the posterior salivary glands of cephalopods[J]. Nature, 1959, 183(4669): 1192-1193.

[7]Nixon M. Is there external digestion by Octopus?[J]. Journal of Zoology, 1984, 202(3): 441-447.

[8]Boyle PR, Knobloch D. Hole boring of crustacean prey by the octopus Eledone cirrhosa (Mollusca, Cephalopoda)[J]. Journal of Zoology, 1981, 193(1): 1-10.

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