The sunfish that was neither resisted nor ran away by the sea lion, why hasn't it become extinct so far?
First correct a common sense error. It is often said that the seal is a sea lion. In fact, it is not a seal. It is a sea lion. In addition, a sunfish is just a common name. The standard name should be a carp."The picture made a deep impression. The rollover was utterly unrecognizable by the sea lions like a big pie, but there was no escape or resistance, but just waiting to die. Why?
△ Sea Lion treats rollovers as cakes
What is a rollover?
First of all, let me briefly introduce the rollover 鲀. The rollover 鲀 is named after people often seeing their bodies floating on the water surface, just like overturning the car. In fact, it is in the sun, and it sometimes stays for a long time.To find food in cold water, you need to bask in the sun to warm up your body. In addition, you can attract seagulls to help it clear the parasites on it.
The shape of the flipper is very unique. Its body is very tall, but it is short and flat. From the side, it is oval, and when it is viewed from the top, it is flat. Its tail is completely degraded.Even the tail vertebrae are gone, and the back of the body to the dorsal and anal fins is over. It looks like there is only a fish head.
△ The "rollover" of the rollover 鲀 is actually sunbathing
Flamecatcher is not a fish, but a general name for a family, including 3 genera and 5 species of fish. Among them, Fowlfish include Mola mola, Mola ramsayi and Mola tecta 3. There are two species in this family: Masturus lanceolatus and Ranzania laevis.
Why not run away or resist?
The main natural enemies of Sunshade are killer whales, large sharks and sea lions. It neither escapes nor resists when it encounters enemies, it only suffers blindly, it depends on the natural enemies' life and death. Why?
Why not run? Because you ca n’t run. Whether it is a cetacean or a fish, swimming is mainly driven by the tail fin, while the flipper tail fin is degraded and replaced by a "false tail" fused with the dorsal and pectoral fin ends.Swimming does not help. Its pectoral fins have no driving function and can only play a role in assisting balance. Its swimming is swinging by the dorsal and anal fins. Some people think that its swimming posture is like dancing Mambo, so theyIt's called Mambo. The carolina swims very slowly, only 0.4-0.7 m / s, slower than people walking.
△ normal swimming posture of a rollover
Why not resist? Because of the inability to resist. The Sundial is very docile and can only eat small animals such as small fish, squid, crustaceans, jellyfish, and starfish. Its mouth is particularly small, its teeth have become a beak, and it is the only one in the whole body.The teeth are in the pharynx pharyngeal teeth. Don't say that this small mouth hurts the enemy, you can't even bite it, because its mouth cannot be completely closed. You can't find a weapon to hurt you.To the enemy.
Therefore, it is not that the carousel is willing to be beaten, but it does not have the ability to escape and resist at all. It is similar to the hippo encountering a group of lions on land. The carousel is more miserable than a hippo. Hippos have large mouths and long teeth.Deterrence, the rollover is nothing.
△ Rollover, gentle giant
Overturned 翻 so vegetables, why haven't they become extinct?
Encountered enemy can only endure the rollover car that can multiply to this day because it has the following tricks.
First of all, the body size is large. The carcass is too large and is the largest hard-bone fish. Adults usually weigh 250 kg to one ton, up to 3.3 meters and 2.3 tons. The Lagrangian carcass is shorter than the body, but because it is more robust, The weight may be heavier. At the beginning of the article, the sea lion's rollover cricket is only a minor individual, once it grows into an adult sea lion, it will be difficult to hurt it.
△ The rollover captured in 1910, weighing 1.6 tons
Second, the thickness of the skin. The skin of the clamshell is too thick, the abdomen skin can be up to 7.3 cm thick, and it is rich in reticular collagen. The surface is covered with a layer of fine teeth and mucus, which is very rough. According to the researchers' measurement,The skin of a 1.2-meter jumbo rollover is 3.8 centimeters thick. The skin of an adult jumbo roll cannot be bitten by predators.
Again, the meat is unpalatable. Do you think you can have a meal without wearing the thick skin of the carcass? Dreaming! The meat of the carcass is very poor, with a thick gelatinous layer under the skin.It can account for 44% of the total body weight. Killer whales and sharks only need to take a bite to know that this is a prey with very low nutritional value, and they are unwilling to eat it.
In the northwest Atlantic longline fishery, only one of the 684 hooked sunfishes has been bitten by a predator. This is a miracle in ocean longline fishing, indicating that everyone does not like to eat it, free of chargeDo n’t. The sea lion hunting and killing the rollover is often out of game psychology, rather than really want to eat it. The bad-looking sea lion often tears off the fins of the juvenile rollover, watching the rollover sink to the bottom of the sea and waiting to die.
△ sea lion hunt and rollover
Finally, the largest magic weapon ever reproduced by the sunken carp is its ability to produce. Adult female sunken carps can release 300 million egg cells at a time, which is the largest of all vertebrates. Although the survival rate of fry is extremely low, it is said that it is only one ten millionth.One, but even then, female flippers can have 30 offspring to reach adulthood per spawn.
The fry of Sunfish is only 2.5 mm long and weighs a few milligrams. It can grow to more than 60 million times its birth size as an adult. It is the most extreme of all vertebrates. And this fish grows fast. Monterey Bay AquariumIt took only 15 months for one of the juveniles to grow from 26 kg to 400 kg.
△ The adult rollover is huge
The evolution of creatures is to adapt to the environment. As long as any creature can reproduce, it has been successful. However, in the eyes of the public, the sunfish is really "disused". Bai has grown so big that he can only rely on skin.It is thick, unpalatable, and able to survive until today. Despite its amazing breeding ability, Sunfish is not a common species in the sea, which shows that the evolution of this fish was not very successful.
△ People make rollovers for food
Now, rollovers are facing a new challenge—human threats. Japanese and Taiwanese do n’t find it unpalatable, making it a delicious dish. Another threat is the pollution of plastic bags, which may turn plasticThe bag is swallowed as a jellyfish, causing suffocation or starvation alive. Now, the World Conservation Union has rated the sunken carp as a vulnerable species and it needs people's protection.
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