Some time ago, there was a "crab strong" on the Internet that was very popular. It is a common meat ball near the side crab, which was thrown into the fish tank as feed, but it was "hand and foot" by the fish and was still strong.
Therefore, the feed took the initiative to raise it with compassion, and finally the "crab strong" after successfully molting, all the legs grew back and regained a new life.
Crabs are not easy to grow
Doesn't that sound amazing?
It's not because it's rare, this matter has to be put aside for you, you may not be able to wait for the little crab to be reborn, it has already let it go.
Crab: If you only break one leg at a time
Why can "crabs be strong" regenerate in ten limbs? In fact, not only crabs, but also shrimp, spiders, insects, etc. that belong to the same arthropods have a certain degree of limb regeneration ability.
If the crab's leg is bitten by other animals and cannot break free, it will often break the leg from the root in order to get rid of it quickly. The fracture will soon close, and the new limb will slowly grow at the fracture, gradually forming a nodule wrapped in a sac formed by chitin, called a "limb bud". When the molting shell is reached, the limb buds are freed from the shackles of a few butyric sacs, and the new legs are stretched out. The newly grown legs tend to be smaller than the original, and it takes several molts to return to their original form.
Small body, big crab legs
Image source: Figureworm Creative
Although crabs have ten legs (including crab claws), the impact of dropping one or two is not too big, but if the legs are broken too much, it will directly affect the crab's feeding and movement ability, and the regeneration of broken legs also needs to consume a lot of nutrients.
Need to eat more but can not run fast, the life of the crab with broken legs is bound to be quite difficult. If the "crab strong" with all limbs and no mobility was in the sea, it would have become a living can for other animals.
Or accidentally get on the table
Writing this, I suddenly remembered a giant river prawn that I kept in the fish tank in my dormitory in college, because it always preyed on the peacock fish in the tank, so I broke off two of its pliers. But every time it sheds its shell, the pliers grow back, so it has to be broken again...
So, if I raise a crab and break only one of its crab legs to eat each time, will there be a steady stream of crab legs to eat in the future? Don't you say, it's really like this! The United States lives a Florida stone crab (menippe mercenaria), and every time it is caught, it can only be eaten by breaking the legs of the male stone crab and then releasing it.
This big crab leg must be delicious!
Image source: Florida Fish and Wildlife Conservation Commission
Lizard: Half-cut tail flicks in your face
There are too many animals that can grow again after breaking arms and legs, and some of them can regenerate more than just arms and legs!
Many lizards survive by breaking their tails in an emergency, breaking their tails by strongly contracting their tail muscles, and using the fallen tail to attract the attention of predators to escape, a behavior called "self-cutting".
A lizard with a severed tail
Image source: reptilesmagazine.com
If you think about it, you are fighting with a person, and the other party suddenly twists his arm down and throws it in your face, and asks if you are afraid of !!!
Geckos (yes, geckos are one of the lizards) are well known for their self-cutting behavior, and their broken tails can grow again, so many people think that geckos play with broken tails every day. But if we could actually interview a gecko, it would surely tell you that it would never give up its tail easily unless it had to.
Some types of lizards will accumulate a lot of fat in the tail in case of emergency, the tail is the "safe" they carry with them, like the common pet lizard leopard pattern palace, fat tail palace and other types of tail in the hoarding enough fat, even as thick as the head, this is a lot of savings.
Look at the fat tail shougong this big fat tail
Image source: ultimateexotics.co.za
The lizard escapes by cutting itself, which is equivalent to throwing away our wallets in order to escape from the hands of the most vicious robbers.
Like crabs with broken legs, lizards with broken tails face difficult situations: not only are the accumulated nutrients gone, but they also need to spend nutrients to grow new tails; without the tail as a balancing organ, the movement becomes less flexible; and they may also be bullied by their peers because they do not have a tail. The most terrible thing is that if you encounter "robbers" again and again, you don't have a "wallet" to lose... It has to live with caution until a new tail grows.
Doesn't that sound sad? And even sadder, the lizard's severed tail moves!
The figure below is high energy
However, it is not yet clear why this is so, perhaps to attract the attention of hunters.
Some hunters will eat the tail of a lizard, while others will not. It's a shame that the uneaten tail is left there, so some lizards will go back and eat their own tails.
Sea Cucumber: "Split the corpse" yourself, defend against the enemy
Speaking of sea cucumbers, my first reaction as a Shandong person is: roasted onions.
Hungry
Far from it, this article does not talk about seafood cooking.
The sea participates in starfish and sea urchins are the same echinoderms, but the starfish has less thick skin, although the sea urchin is yellow but more thorny, compared to only the sea cucumber soft lying on the stomach to look at it is good to bully, want to eat it is not only us humans. So what do sea cucumbers rely on on the seabed?
In addition to camouflaging and spitting out narcotic black juice to confuse predators by its own shape and color, sea cucumbers mainly rely on "corpse splitting" to defend themselves:
Spit "silk"
Little Fish: Wide fear!
Spitting out a tissue called cuvierian tubules in the body, the cuvierian tubules, which rapidly expand into tubular white strips when exposed to water, not only have a special smell, but also have a strong stickiness, enough to make predators satisfied.
Spit intestines
The intestines are all for you, let me go
Image source: Documentary "Everything Nourishes"
Some types of sea cucumbers will excrete their intestines in an emergency, and the intestines play the same role as the gecko's tail, and if the hollow sea cucumber in the abdomen is lucky enough to escape, it can grow a new set of intestines after a while.
Severed head
Don't you want my head? Screw it down for you!!
Some sea cucumbers in the case of the above means do not work, will simply take the initiative to screw their heads off, and even split themselves into several segments, in order to at least one section can escape, under the right conditions after a long time, some of these "ginseng segments" can also grow their heads again, back into a complete sea cucumber.
Sea Slugs: This body is dirty and can't be wanted
Sea slugs are a class of marine mollusks that are so named because of their resemblance to slugs, and they also have a strong regenerative capacity. Recently, Japanese scientists discovered that two species of slugs (elysia cf.marginata & elysia atroviridis) can also grow new bodies with only one head left.
A cute and loving sea slug head
Image credit: sayaka mitoh
At first, it was found that a sea slug in a water tank seemed to have been "decapitated", and everyone thought it was dead, but after a few hours, the lone sea slug began to eat algae, and grew a new body in the next three weeks.
Although the headless sea slugs can continue to live for days to months, they can never grow new heads, and eventually they will die.
Three days after the severed head, the head of the sea slug is still spinning around the detached body.
The reason why they actively screwed off their heads is not the same as the severed heads of sea cucumbers. After observation, the process of "self-slugs" is very slow, it takes several hours to be in a different place, and in the case of artificial stimulation, there is no sea slugs actively beheading, so it is unlikely to be a means of escape like the severed head of sea cucumbers.
Sea slugs are parasitized by small crustaceans, and scientists believe that these sea slugs that screw off their heads may be to get rid of the parasites in their bodies. In the comparative trial, 3 of the 82 parasitic sea slugs actively severed their heads, 2 of which eventually grew new bodies, while none of the 64 sea slugs that were parasitically had any severed heads.
The severed heads of two species of sea slugs regenerate
However, there is another important problem: although the sea slugs with only their heads left can continue to eat, they have no digestive organs! How do you absorb nutrients without digestive organs? Where does the energy of the new body come from? Is it necessary to violate the law of conservation of energy?
It turns out that the energy supply method of these little guys in the "regeneration" stage is different from usual. With only the head left, the sea slugs transfer the chloroplasts in the algae they eat into their own bodies, and the photosynthesis of these chloroplasts energizes their regeneration process, which is equivalent to temporarily installing solar panels when the internal combustion engine is dismantled.
However, because the absorbed algal chloroplasts will fail in a few days, this can only be used as a temporary emergency, and the sea slugs still have to rely on normal feeding to survive after growing a new body.
Oh yes, some sea slugs will eat their own kind.
Storm inhalation
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Written by | Song Xiaomeng
WeChat Editor | Xie Shuang