Open the search engine and enter the keyword "the most poisonous snake in the world". I'm afraid you will get two different answers. Hydrophis belcheri and Oxyuranus microlepidotus inland Taipan snakes are called the most poisonous snakes in the world by many websites and books at home and abroad, so how to distinguish these two snakes?
If you want to know who is the most poisonous snake in the world, you must first find out how this "most poisonous" snake was selected. First of all, we need to know the toxicology experiment and the statistics of toxicity intensity.
There are many statistics showing the toxicity intensity, such as the absolute lethal dose (LD 100? ), LD50, LC50, MLD and LD0. In general, LD50 and its corresponding confidence interval are the most commonly used statistics obtained as a dose-response model, because they are the most sensitive and representative (the nearly straight part of S curve, the middle part of normal distribution). It should be noted that the number after LD/LC should be the lower corner mark.
Lethal dose 50% (LD50) refers to the minimum toxicity/drug dose that can cause half of the death of experimental animals, usually expressed by the logarithmic value of the lethal dose of drugs. It should be noted that the smaller the LD50 value, the greater the toxicity, that is, the toxicity is inversely proportional to the LD50 value, because this is the minimum dose that can cause half of the experimental animals to die. Experimental animals usually use mice or rats, so the value of LD50 is also relative to mice.
There are four methods to detect LD50 of snake venom: subcutaneous injection (SC), intravenous injection (IV), intramuscular injection (IM or IC) and intraperitoneal injection (IP). Among them, the result of subcutaneous injection is closest to the real situation of poisonous snake bite, so it has become the most commonly used way of receiving poison. Now focus! The same poison, the same dose, if the contact route is different, will cause different toxic reactions. In view of this, when explaining the dose of a poison, we must also explain the route of exposure. Therefore, the LD50 values measured by different exposure paths cannot be compared horizontally.
After reading the scarlet letter above, let's get to know the two candidates formally.
The first thing to introduce is the famous inland Taipan snake Oxyuranus microlepidotus.
Tom Charlton
The inland Taipan snake is only distributed in the inaccessible inland areas of Australia, with a large size, with an average total length of 2 meters and a record of 2.5 meters. Body color yellow brown or olive brown, etc. ; The front edge of the dorsal scale is dark brown or black, patched into mottled horizontal stripes; The ventral surface is yellow with brown spots. Interestingly, the head color of inland Taipan snake changes with the seasons. In the cold season, the head color will turn dark brown or dark brown to absorb more heat. In warm seasons, the head color will turn olive yellow to avoid absorbing too much heat. This phenomenon of body color changing with seasons is also reflected in the other two species of Taipan snake.
The head color of inland Taipan snake will be lighter in summer.
Distribution map of inland Taipan snake
The inland Taipan snake almost only feeds on small rodents in the wild, especially house mice, which accounts for most of its diet. They are efficient rodent killers, often shuttling between rat paths and the ground in search of prey. Venom has also evolved to be more effective for mammals. They don't let go after injecting venom like other snakes. Strong venom can kill prey almost immediately. It is estimated that if someone is bitten by the inland Taipan snake, the time left for him will not exceed 45 minutes. Fortunately, they live in the inaccessible inland areas of Australia. They are gentle and shy, and there are few biting accidents. So far, there are no reports of such snake bites. The latest bite accident occurred on 20 12. /kloc-A 0/7-year-old boy was bitten by the inland Taipan snake illegally raised by him. Fortunately, Australia has rich experience in dealing with snake wounds. After injecting multivalent antivenom in the shortest time, this lucky Xiong Haizi can be regarded as having recovered his life.
This little mouse is the main prey of inland Taipan snake. via。 Rattus tomentosa
Let's briefly introduce the sea snake Hydrophis belcheri. Why is it simple? Because there is too little introduction to it. Let's just say that there are no more than five photos of suspected sea snakes on the Internet and in various books, and most of the photos found by Google and Bing are wide-tailed species. At present, the only photo that can be confirmed is the following photo of a normal sea snake specimen.
Photos of normal specimens of sea snake Bayonet
Bayonet sea snakes inhabit the waters of New Guinea, Philippines, Thailand, Vietnam, Indonesia and northwest Australia. They are gray, with about 60 dark stripes on the back and 34 rows of scales in the middle, with a total length of about 1 m. The etymology of the specific modifier belcheri comes from Sir Edward Belcher, the discoverer of positive type specimens.
We heard from TV and books a long time ago that the sea snake is the most poisonous snake in the world, because once its prey escapes in the sea, it can no longer be found by smell, so if it wants to kill its prey in the shortest time, it will evolve into a stronger venom than snakes on land. Fortunately, the anterior sulcus teeth of sea snakes are short, and the opening angle is much smaller than that of terrestrial cobras. In addition, due to their gentle personality, there are few reports of injuries.
Data-based decision-making
Now the answer is about to be revealed Let's look at the LD50 values of two kinds of snakes.
The LD50 of mainland Taipan snake injected subcutaneously was 0.025 mg/kg, and the detoxication amount was about 44.0-110.0mg.. ..
The LD50 of intramuscular injection of sea snake was 0.65438 0.55 mg/kg.
As mentioned above, the lower the LD50 value, the greater the toxicity, but the horizontal comparison of the same exposure route must be carried out. At present, the LD50 of sea snakes with bayonets only under intramuscular injection can't be compared with the subcutaneous injection value of inland Taipan snakes, so let bayonets make a comparison before other snakes. The intramuscular LD50 of the salmon was 0.09 mg/kg. The intramuscular LD50 of Hydrophis melanosoma is 0.082 mg/kg, and the toxicity of these two species is higher than Berberian, so the throne of "the world's first poisonous snake" is definitely untenable. Then the LD50 of subcutaneous injection was compared with that of the smooth swordtail sea snake, the black ring sea snake and the inland Taipan snake, and the LD50 of subcutaneous injection of the smooth swordtail sea snake was 0.264mg/kg；. The LD _ (50) of the subcutaneous injection of the black ring sea snake is 0.11mg/kg, which is quite different from the inland Taipan snake's 0.025 mg/kg. From this point of view, the sea snake bayonet is not the most poisonous snake in the world, and its toxicity ranking among sea snakes is not on the list. So how did it "usurp the throne"?
In fact, it was an oolong caused by a popular science book. In the 1990s, the Smithsonian Institution published a set of popular science books on animals, called Smithsonian Answer Book, which explained many questions about animals in the form of questions and answers. Among them, the author of Snake ignores that different infection modes will have different LD50 values, and mistakenly thinks that the sea snake bayonet is the most poisonous snake in the world. Due to the early publication and large circulation, the "Oolong" spread more and more widely, and even almost pushed the inland Taipan snake off the throne of "the most poisonous snake in the world". So! Young people should not listen to the wind and rain, but be responsible for the deviation in the report!
It is this popular science reading "Amazon.com" that triggered this "Oolong"
Finally, it ended with that famous saying-"All poisonous snakes are poisonous."
refer to
Fry, B. Associate Professor, School of Biological Sciences, University of Queensland (20 12. 02. 24). "LD50 snake venom-list of available data, classified by injection route". venomdoc.com。 (Archived) Search on 20th13 years 10/0/4 days.
Australian Venom Research Unit (1 month 1 1, 20 14). Facts and figures: the most poisonous snake in the world. University of Melbourne. Retrieved July 65438, 20 14.
Australian Venom Research Unit (1 month 1 1, 20 14). Facts and figures: the most poisonous snake in the world. University of Melbourne. Retrieved July 65438, 20 14.
LD50。 [EB/OL]。 /oldsite/ld50tot.html
Viper [EB/OL]。 Https://en. Wikipedia. org/wiki/ poisonous snake #cite_note- 12
LD50 in Viper? . [EB/OL]。 http://snakedatabase.org/pages/LD50.php
Shen Jianzhong. Animal toxicology [M]. China Agricultural Press, 2002.
Text/Snake Seeker Qi Shuo