Eating "Five Poison" cakes at Dragon Boat Festival: what are the five poisonous creatures on the patterns?

When it comes to Dragon Boat Festival, the first things that come to mind may be zongzi, dragon boats and Qu Yuan, but according to textual research, as early as the Spring and Autumn period before Qu Yuan, ritual activities were already regularly held on the fifth day of the fifth lunar month in places such as Chu, Wu and Yue.The purpose of these activities was mostly to ward off evil spirits, and we can still see traces of these activities today: wearing scented sachets, hanging calamus, burning mugwort, drinking realgar wine and so on were all means used in ancient times to drive out evil and toxins.

Dragon Boat Festival is not just about dragon boat racing. Image: David Sun / flickr

In northern China, there is also the custom at Dragon Boat Festival of eating "Five Poison cakes", although these cakes are just ordinary pastries with five-poison patterns stamped on top or five-poison figures pressed into them, this still well reflects people's wish to "eat up" these poisonous insects so that they can no longer harm the world.

The day before yesterday, Five Poison cakes appeared on CCTV's "Chaowen Tianxia" program.

So which five species are the "Five Poisons"? The most common "Five Poisons" patterns on Five Poison cakes arecentipede, snake, scorpion, toad and gecko, let us get to know them one by one.

Warning for the whole article: fear of insects and fear of snakes

Note, this is not a drill

！！！

Centipede

Frequency of appearance: ★★★☆☆

Danger level: ★★★☆☆

The Chinese red-headed centipede (Scolopendra subspinipes mutilans), also called the Chinese red-headed centipede, is mainly distributed in China and Japan, with an average body length of 20 cm. Image: wiki commons

Even people seeing a centipede for the first time will be startled by its long, many-legged, alien form, and the childhood legend of the "centipede spirit" sucking out human brains must also have left no small shadow on our young minds.

Many legs are probably the most lasting impression centipedes leave on people, so centipedes are also called "hundred-legged worms". However, generally speaking,centipedes usually do not have that many legs. Take the Chinese red-headed centipede, which is relatively common in the Jiangnan region: a fully mature individual has only 21 visible segments (actually 25 segments, of which the first segment and the last three are small and extremely inconspicuous). Centipedes belong to the subphylum Myriapoda, class Chilopoda, and each body segment has only one pair of legs, so apart from the antennae on the head and the elongated terminal legs at the rear, the Chinese red-headed centipede has only 20 pairs of legs used for walking, that is,just 40 legs。

The true "hundred-legged creature" should be the millipedes, which also belong to the subphylum Myriapoda but are placed in the class Diplopoda; they not only have many body segments, but each segment has two pairs of legs, so the number of legs can easily reach more than a hundred pairs.

A slender, many-legged centipede on a leaf. Image: Palmfly / wiki commons

What puts centipedes firmly on the list of venomous creatures is a pair of specialized legs on their first trunk segment -the forcipules。The forcipules of centipedes are sharp and powerful, and are connected to venom glands. When a centipede hunts, it first catches its prey by surprise with its first few pairs of walking legs, then pierces the prey's body with its forcipules andinjects venom. Centipede venom mainly contains various enzymes, such as phospholipase, protease, hyaluronidase and so on. Among them, phospholipase is thought to damage cell membranes, especially those of nerve cells; protease and hyaluronidase can break down the prey's tissues.

Ventral view of the Megarian banded centipede (Scolopendra cingulata), note its forcipules. Image: Fritz Geller-Grimm / wiki commons

These venom componentsare extremely lethal to both insects and vertebrates. In nature, centipedes feed on other insects, birds and small mammals, andif accidentally bitten by a centipede, subcutaneous bleeding, edema, tissue necrosis and even death may occur。

Snake

Frequency of appearance: ★★☆☆☆

Danger level: ★★★★★

The sharp-nosed pit viper (Deinagkistrodon acutus), commonly known as the five-step snake, seven-step snake, hundred-step snake or qishe, is a venomous snake in the subfamily Crotalinae of the family Viperidae. Image: Sam Martin

Although in tradition the "chief of the Five Poisons" is the centipede, when it comes to the number of people bitten and killed each year,venomous snakes are the kings of poison - you should know that about 50,000 people worldwide die each year from venomous snake bites.

For the entire snake family, venomous snakes make up about 1/3 to 1/4 of the total. Of the more than 200 species of snakes distributed in China, about 50 or more are venomous. The snakes that pose a threat to humans are mainly concentrated inthe family Elapidae(Elapidae) andthe family Viperidae(Viperidae). In the term "snake hui", the character "hui" is generally believed to refer to venomous snakes, especially those of the family Viperidae.

Fujian bamboo pit viper of the family Viperidae. Image: Evan Pickett / wiki commons

The reason venomous snakes are terrifying comes from thosesharp fangs and deadly venom. The reason cobras and vipers are the main groups causing envenomation is thattheir fangs are large and located at the front of the upper jaw, making it easier for them to pierce the prey's body when attacking. In contrast, although some colubrids and sea snakes also have venom glands, their fangs are located at the rear of the jaw and do not easily pierce the prey's body, so their danger is relatively lower.

For cobras and vipers, the two differ slightly in their fangs and the way they use venom. The former have a groove behind the fang for transporting venom, so they are calledgrooved fangs; while in vipers the venom transport route is enclosed into a duct, calledtubular fangs. Cobra venom contains more substances such as cholinesterase and polypeptides, which can block the transmission of nerve impulses to muscles, so it is calledneurotoxin; while viper venom additionally contains protease, hyaluronidase and so on, which can extensively destroy tissues and cause hemolysis or coagulation, so it is calledhemotoxin. Of course, these "neurotoxin" and "hemotoxin" are only rough divisions,almost all venomous snakes use these two types of toxins in combination。

Scorpion

Frequency of appearance: ★☆☆☆☆

Danger level: ★★★☆☆

The emperor scorpion (Pandinus imperator) is the largest scorpion in the world, with a body length of up to 20 cm. Relative to its size, its venom is not strong. Image: shutterstock

Scorpions are quite closely related to spiders, and the most obvious difference between the two is in the abdomen: their abdomen does not merge into a spherical big belly like that of spiders, but gradually tapers, andthe last segment is needle-shaped and contains venom glands. Scorpions, like spiders, also have chelicerae, since they are both members of the subphylum Chelicerata, except that the chelicerae of scorpions are not connected to venom glands.

Basic body structure of arachnids: (1) legs, (2) cephalothorax, (3) abdomen. Image: wiki commons

The composition of scorpion venom and spider venom is very similar; both aremade up of small peptides. Scorpion toxins can be divided into two major categories according to molecular size, but both categoriesact on neural receptors: one type has a slightly larger molecular weight and acts on sodium ion channels on the surface of nerves; the other type has a smaller molecular weight and acts on potassium ion channels, chloride ion channels and so on. Both kinds of scorpion toxins can paralyze prey.

However, scorpion venom and spider venom differ greatly in their targets. Research has found that neurotoxins accounting for about 10%-50% of scorpion venomhave a strong lethal effect on mammals, while neurotoxins specifically targeting insects make up only about 1%. Why do scorpions have such a grudge against mammals? One possible explanation is that scorpions diverged earlier from arachnids and mainly live on the ground; compared with the later-appearing, more arboreal spiders, they are more likely to encounter mammalian predators, so under predation pressure from mammals, it is reasonable that scorpions with a "killer move" against mammals survived and developed to this day.

In China, you may see the East Asian scorpion. Image: UniProt

In northwestern China, scorpions, especiallythe East Asian scorpion(Buthus martensi), are fairly common indoor venomous creatures. Fortunately, it is one of the less venomous members of the family Buthidae, and being stung by it generally causes only redness, swelling and pain. Its relatives, however, such asthe Israeli deathstalker(Leiurus quinquestriatus), are not so easy to deal with; because it likes to hide in clothing folds or shoes, there are often cases of severe stings, which can be fatal for children or frail people. Buthidae is the family with the most venomous species in the order Scorpiones, and most venomous scorpions belong to this family. Some larger, more ferocious-looking scorpions, such asthe emperor scorpion(Pandinus spp.), have weak venom and rely more on their two powerful pincers for hunting. For scorpions,usually the more developed the pincers, the weaker the venom, and vice versa. It seems that whether to favor physical attacks or chemical attacks is also something that needs consideration.

Toad

Frequency of appearance: ★★★★☆

Danger level: ★☆☆☆☆

In ancient times, the toad was an animal that made peoplefeel both love and hate. As for hate, the toad is listed among the "Five Poisons", and "a toad wanting to eat swan meat" also depicts people's contempt for toads; as for love, people also regarded toads as an auspicious symbol, especially the three-legged "golden toad", which was seen as a symbol of bringing in wealth and treasure. But no matter how you look at it, it is a consensus that the toad is poisonous. When we were children, old people often said that urine sprayed by a toad would make people grow ringworm, and that touching a toad would make people grow bumps like a toad, warning us little brats. So is toad poison really that powerful?

The common toad (Bufo bufo) is one of the common toad species in China. Image: shutterstock

The most common toads in China are the common toad (Bufo bufo), the Chinese toad (B. gargarizans) and the black-spined toad (B. melanostictus); the appearances of these three toads are quite similar, together forming the classic image of the "toad". Behind the eyes of these toads there is a large swelling, calledthe parotoid gland. Thewhite milky liquid secreted by the parotoid gland - toad venom- is the source of the toad's toxicity. The chemical composition of toad venom is relatively complex, including bufogenins, bufotoxins and bufotenines. Among them, most bufogenins have a structure similar to cardiac glycosides, which can increase heart rate and strengthen heartbeat, while bufotenines mostly have hallucinogenic ability.

Chinese toad. Image: DrewHeath / wiki commons

For toads, the main purpose of secreting venom is self-defense.These toxic components only take effect after contacting exposed mucous membranes and being absorbed into the blood; for skin, the stratum corneum can well isolate the venom. Therefore, common poisoning deaths often occur in cats and dogs that accidentally eat or lick toads, while cases of human poisoning aremostly because of greedy eating of toads that have not been properly cleaned, or taking folk remedies made from toads. As for toad urine, it only contains water, inorganic salts and a small amount of ammonia, and there is nothing special about it.

Gecko

Frequency of appearance: ★★☆☆☆

Danger level: ☆☆☆☆☆

The Japanese gecko is distributed in China, Korea and Japan, and is one of the gecko species often seen indoors and outdoors. Image: takuyamorihisa.com

Compared with the above several truly venomous guys,the gecko was included in the "Five Poisons" purely by being "caught in the crossfire". Species commonly seen indoors and outdoors in China, such as Swinhoe's gecko (Gekko swinhonis), the Japanese gecko (G. japonicus), the web-footed gecko (G. subpalmatus) and so on,are all non-venomous. The reason ancient people mistakenly regarded geckos as poisonous creatures was probably simply because they were amazed by their peculiar abilities: mostly hiding by day and coming out at night, being able to cling to walls and crawl silently, and leaving behind a writhing tail when startled. Of course, when we were little, we all heard legends that gecko urine would blind people's eyes, or that a gecko's tail would crawl into people's ears and make them deaf, butIn fact, none of these things can actually happen。

Take gecko urine for example -Actually, geckos do not urinate. Like birds, geckos' metabolic product is uric acid. As their waste passes through the ureters, bladder and other parts, water is reabsorbed, while the water-insoluble uric acid combines with sodium, potassium and other ions to form urates, which after entering the cloaca mix with feces and are expelled from the body. It is precisely this highly efficient way of reclaiming water that has enabled geckos and other reptiles to adapt to dry environments.

The common house gecko in China, Hemidactylus frenatus. Image: iNaturalist / wiki commons

The gecko's ability to "drop its tail" is also astonishing. When a gecko's tail is grasped or it is startled, the tail muscles contract strongly, causing the fracture planes between the caudal vertebrae to separate, completing the "tail drop."The severed tail writhes due to spontaneous internal muscle contractions, thereby drawing the predator's attention and giving the gecko a better chance to escape. The writhing of the gecko's tail is unconscious, and it will not "crawl into your ear" as legend says. For a gecko that has dropped its tail, although the tail can grow back, the newly grown tail will no longer contain vertebrae inside; instead, a cartilage tube takes their place, and the distribution of muscles also changes, so that the newly grown tail will not break off again. In addition, tail loss also has a certain impact on the gecko's reproduction, because for a gecko,the tail is a "warehouse" for storing fat and other nutrients. From this perspective, this "sacrifice the rook to save the king" strategy of the gecko not only costs it nutrients, but also earns it the bad name of "poisonous insect." Is this fortunate or unfortunate?

This article comes from Species Calendar author @Feixue, graphics by @Laomao.

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