05/09/2026
【標本秀 Specimen Showcase｜雙毒護法・蛇中盜賊 The Double-Venom Defender】*Eng below* 🧛🏻若你覺得長著毒牙的蛇已夠駭人，那等你見識過這位會從晚餐裏萃取毒物的高手，才知天外有天。有請紅脖游蛇 𝘙𝘩𝘢𝘣𝘥𝘰𝘱𝘩𝘪𝘴 𝘩𝘦𝘭𝘭𝘦𝘳𝘪（Schlegel, 1837）🐍！這位狡黠的亞洲游蛇科成員，不僅能自行產生毒素，還會從獵物身上偷取毒質。正因如此，牠既是能咬傷注毒的「毒蛇」，又是碰不得也吃不得的「毒物」，堪稱蛇類世界中罕見的雙重威脅！
這種半水棲的獵手是亞洲特有物種，分佈範圍從孟加拉、尼泊爾、印度，延伸至中南半島、馬來西亞及中國（包括香港）。牠鍾情於潮濕環境💧，常見於濕草地、沼澤、樹沼、稻田🌾、池塘及緩流河岸🏞️。
外觀極具辨識度的紅脖游蛇體態纖細，體長一般為 60 至 110 厘米（雌性明顯較大），披著橄欖綠色調🫒，點綴黑色棋盤格紋🏁與黃綠色斑彩。最奪目之處，莫過於頸部與頭部那漸變的紅黃警示色💊——這正是其中文名字的由來。身體中段的稜鱗有助於攀爬與抓地，而從眼睛延伸至三角形嘴角的深褐或黑色眼紋👁️🗨️，更添其標誌性面容。作為日行性獵手☀️，牠在白晝出沒於水邊搜尋獵物。牠屬肉食兼魚食性，其食譜涵蓋蛙類等兩棲動物、蜥蜴🦎，還有關鍵的——蟾蜍🐸，以及魚類與小型哺乳動物。
紅脖游蛇在其著名的紅色頸部藏著祕密化學倉庫🧪，也就是特化的頸腺，用以儲存從有毒蟾蜍身上掠奪的毒素☠️。由於對蟾蜍毒素具有抗性，牠能將這些化學物質隔離並累積於腺體之中；當受到驚擾或觸碰時，更會主動爆裂腺體💥，將乳白色的蟾蜍毒素分泌液釋出於皮膚表面。任何企圖吞食牠的天敵，因此都可能吃上一頓致命毒餐。相關毒素可引發流涎、抽搐、心跳過快，甚至癱瘓。你沒看錯——牠將獵物的防身武器據為己用🤺，簡直是把晚餐變成自己的盔甲。
以為這已夠駭人了嗎？別急，牠還藏著一套強力而獨立的後備方案。在其口腔後方，隱藏著擴大且具溝槽的後溝牙🦷。這些牙齒與上顎的杜氏腺相連，能分泌毒液，當牠發動咬擊時，毒液會沿溝槽滴入傷口💧。雖然其毒力足以引發噁心、內出血🩸，甚至可能導致消耗性凝血病（凝血因子過度消耗而無法正常凝血），但實際對人類的風險其實不高。香港平均每年約有 89 宗蛇咬個案（2022 至 2024 年數據），但當中並無死亡個案，所有患者經及時治療後均完全康復，且無一宗與紅脖游蛇有關。因此，謹慎為上，但毋須過度驚慌。
其實，紅脖游蛇一般比較害羞🫣。面對威脅時，與大多數其他蛇類一樣，牠傾向退避。若受挑釁，牠會先使出一套巧妙的擬態伎倆🤡，將頭部壓扁成矩形，身體膨脹，扮成更具危險性的蝰蛇，同時發出尖銳的「嘶嘶」聲。倘若套虛張聲勢無效且持續受擾，牠才會發動攻擊，利用其有毒腺體分泌物或帶毒液的咬擊，可謂名副其實的雙重防衛戰士⚔️。因此，若在野外相遇，最好保持距離，靜靜地各走各路，彼此相安無事。
戰場之外，此物種的愛情生活同樣精彩。牠們平日獨居，直至繁殖季節到來，雄蛇便會為爭奪雌蛇展開激烈纏鬥，以身體交纏、角力🤼。勝出的雄蛇會將尾部捲繞雌蛇，再以吐舌👅與身體顫動展開求偶儀式。雌蛇為卵生，每次產下一窩 5 至 27 枚卵🥚，使下一代得以延續這種獨特的雙重毒性特質。
下次走過東南亞的池塘邊，你可細心（但別太靠近）觀察：那片綠意中一閃而過的紅色🔴，或許正是大自然巧妙的化學盜賊，一條攻守兼備🛡️、身懷雙重毒性的蛇正蓄勢待發。
紅脖游蛇🐍有引起你對生態及生物多樣性的興趣嗎？如果你感興趣，歡迎蒞臨香港生物多樣性博物館參觀。我們展示了從珊瑚到哺乳類等各式各樣的標本，讓你深入了解這些迷人生物的生態奧秘。若你喜歡這篇文章，請與朋友分享，並密切關注我們每週推出的精彩生物多樣性故事！
The Hong Kong Biodiversity Museum: Pursuing Successful Environmental Education and Biodiversity Awareness 項目由環境及自然保育基金資助
文：Celia
🧛🏻If you think a snake with venomous fangsis fearsome enough, wait until you meet one that extracts poison from its dinner. Meet 𝘙𝘩𝘢𝘣𝘥𝘰𝘱𝘩𝘪𝘴 𝘩𝘦𝘭𝘭𝘦𝘳𝘪 (Schlegel, 1837), the red-necked keelback🐍— a cunning Asian colubrid that doesn’t just produce its own toxins, but steals them from its prey to become both venomous and poisonous☠️, a rare double-threat in the snake world!
This semi-aquatic hunter is endemic to Asia, with a range stretching from Bangladesh, Nepal, and India across to the Indochinese region, Malaysia, and up to China (including Hong Kong). It’s a creature of wet environments💧, commonly found in wet grasslands, marshes, swamps, rice fields🌾, ponds, and along slow-moving rivers🏞️.
Its appearance is a masterclass in signaling. The snake has a slender body, typically 60 to 110 cm long (with females notably larger), clad in an olive-greenish🫒hue adorned with black checkering🏁and greenish-yellow highlights. Its most striking feature is the vivid gradation into a warning display of red and yellow at its neck and head💊 — the source of its common name. Keeled scales along its mid-body provide traction, and a dark brown or black eye stripe👁️🗨️ stretches from the eye to the edge of its triangular mouth, completing its marked look. As a diurnal hunter☀️, it spends its days searching for prey near water. It is a carnivore and piscivore, consuming a diet of amphibians like frogs, lizards🦎, and critically — toads🐸, as well as fish and small mammals.
The biology of this species gets even more impressive. The red-necked keelback has a secret chemical storage in its famous red neck 🧪 — specialized nuchal glands that store toxins from the poisonous toads☠️it eats. Resistant to the toads' bufotoxins, the snake sequesters these chemicals. When disturbed or touched, it can deliberately burst the glands💥, releasing a milky-white liquid of bufotoxins onto its skin. This makes it a poisonous and potentially deadly meal for any predator, with toxins that can induce drooling, seizures, tachycardia, and even paralysis. Yes, you read that right: it hijacks its prey’s defenses and wears them as its own🤺! Talk about turning your meal into your armor.
And if that isn't enough, it also packs a powerful and independent backup plan. Hidden in the rear of its mouth lie enlarged and grooved rear fangs🦷. These are connected to a Duvernoy's gland located in its upper jaw, which produces venom that dripsinto a wound through the grooves when it bites 💧. While potent enough to cause nausea, internal bleeding🩸, and potentially consumptive coagulopathy (clotting factors become too depleted to allow normal clotting), this venom poses a low actual risk. Hong Kong records around 89 snakebite cases yearly on average (from 2022 to 2024), with zero fatalities, and all patients recover fully with prompt treatment. Among those, none appear to be linked to the red-necked keelback, so be careful, but no need to be scared.
This snake is generally shy 🫣. When faced with a threat, like most snakes, it prefers to retreat. If provoked, it first employs clever mimicry🤡, flattening its head into a rectangular shape and its body to appear like a more dangerous viper, while producing a sharp ‘hissing’ sound. If this bluff fails and it is further provoked, it will strike, utilizing either its poisonous glandular secretion or its venomous bite — a true dual-threat defender⚔️. So if you encounter them, better keep some distance and split paths quietly and peacefully.
Beyond battle, this species has a dramatic love life. Solitary until the mating season, males then engage in intense combat for females, intertwining their bodies and wrestling to establish dominance🤼. The successful male coils his tail around the female and engages in courtship involving tongue flicking👅and body quivering. The female is oviparous, laying between 5 and 27 eggs in a single clutch🥚, leaving the next generation to continue this extraordinary toxic legacy.
So next time you walk past a Southeast Asian pond, look closely (but not too closely) — that flash of red🔴in the green might just be a nature’s ingenious chemical thief, a snake that is both a venomous attacker and a poisonous shield🛡️, armed and dangerous if provoked.
Does the red-necked keelback 🐍 raise your interest in ecology and biodiversity? If your answer is yes, come visit us at the Hong Kong Biodiversity Museum, where we showcase a wide variety of specimens, from corals to mammals, and you can learn more about their fascinating ecology! If you find this article engaging, share it with your friends and stay tuned for our captivating biodiversity stories released weekly📖!
With the funding support of the Environment and Conservation Fund - The Hong Kong Biodiversity Museum: Pursuing Successful Environmental Education and Biodiversity Awareness
Text: Celia
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