金环蛇种

特征

金环蛇全长在一米左右，最长可达一点八米；全身有固定间距的黑黄相间环带，黑色环纹比黄色环纹略宽，幼蛇环带为黑色及灰色；金环蛇躯干有高脊棱，头部椭圆形，略粗于颈部，有矛形花纹，尾巴短钝。

习性及生境

夜行性，栖息于植被茂密和水源充足的小丘和低谷地带，捕食其他蛇类，蜥蜴及小型脊椎动物。

个性温驯胆小，受扰时像其近亲银环蛇般迅速逃走或将头部藏于蛇身下，被捕时则不停晃动身体，但不像银环蛇般剧烈。

繁殖

5月底产卵，每次产卵8-12枚。

潜在危险及毒性

有剧毒，有竖立前毒牙。剧毒足以致命。平均一次排毒量27.5毫克。神经毒为主。人致死剂量10毫克。香港曾有数宗被咬的死亡个案。

日间较温驯，夜间警觉性极高。

分布区域

主要生活在印度东北部和东南亚地区，分布于中国的江西、福建、广东、香港、海南岛、广西和云南。

保护

本种于2023年被收录入《有重要生态、科学、社会价值的陆生野生动物名录》。

The banded krait (Bungarus fasciatus) is a venomous species of elapid endemic to Asia, from Indian subcontinent through Southeast Asia to Southern China. With a maximum length exceeding 2 m (6 ft 7 in), it is the longest krait with a distinguishable gold and black pattern. While this species is generally considered timid and docile, resembling other members of the genus, its venom is highly neurotoxic which is lethal to humans. Although toxicity of the banded krait based upon murine LD50 experiments is lower than that of many other kraits, its venom yield is the highest due to its size.

Description

The banded krait is easily identified by its alternate black and yellow crossbands all of which encircle the body. The head is broad and depressed and it is not distinct from the neck. The eyes are black. It has arrowhead-like yellow markings on its otherwise black head and has yellow lips, lores, chin, and throat. The tail is relatively small, about one-tenth the length of the snake.

The longest banded krait measured was 2.25 m (7 ft 5 in) long, but normally the length encountered is 1.8 m (5 ft 11 in).

Scalation: 15 dorsal scale rows at midbody; sub-caudal scutes undivided throughout, 23–39; middorsal row of scales (vertebrals) hexagonal and strongly enlarged, as broad as or broader than long; anal plate undivided.

Distribution and habitat

The banded krait occurs in the whole of the Indo-Chinese subregion, the Malay Peninsula and Indonesian archipelago, and southern China. The species is common in the states of West Bengal, Odisha, Mizoram, Assam, Manipur, Bihar and Tripura of India, Nepal and Bangladesh, but becomes progressively uncommon westwards in India.

It has been recorded eastwards from central India through Nepal, Bangladesh, Myanmar, Cambodia, Thailand, Laos, Vietnam, and southern China (including Hainan and Hong Kong), Malaysia and the main Indonesian islands of Borneo (Java and Sumatra), as well as Singapore.

In India, it has been recorded from Andhra Pradesh, Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Maharashtra, Northeast India, Odisha, Tamil Nadu, Kerala and West Bengal.

Behaviour

Banded kraits are shy, not typically seen, and are mainly nocturnal. When harassed, they will usually hide their heads under their coils, and do not generally attempt to bite, though at night they are much more active and widely considered to be more dangerous then.

During the day, they lie up in grass, pits, or drains. The snakes are lethargic and sluggish even under provocation. They are most commonly seen in the rains.

Food

The banded krait feeds mainly on other snakes, but is also known to eat fish, frogs, skinks, and snake eggs. Among the snakes taken by banded kraits are:

• Sunbeam snake Xenopeltis unicolor
• Rainbow water snake Enhydris enhydris
• Red-tailed pipe snake Cylindrophis ruffus
• Chequered keelback Fowlea piscator
• Buff-striped keelback Amphiesma stolatum

Venom

The venom of the banded krait mainly contains neurotoxins (pre- and postsynaptic neurotoxins) with LD50 values of 2.4 mg/kg–3.6 mg/kg SC, 1.289 mg/kg IV and 1.55 mg/kg IP. The quantity of venom delivered averages out at 20–114 mg. Engelmann and Obst (1981) list the venom yield at 114 mg (dry weight). The major clinical effects caused by the venom of this species include vomiting, abdominal pain, diarrhoea, and dizziness. Severe envenomation can lead to respiratory failure and death may occur due to suffocation. Banded krait venom can damage the kidneys if injected.

Common names

• Manipuri language – linkhak
• Mizo language – chawnglei, tiangsir
• Kannada – kattige haavu (ಕಟ್ಟಿಗೆ ಹಾವು)
• Karbi language – maipam, rui-teron
• Assamese language – xokha (শখা), xongkhosur (শংখচোৰ), gowala (গোৱালা), bandphora

Bengali – shankhini (শঙ্খিনী), shankhamooti shaanp (শাঁখামুঠি) and rajsap (king snake) in Birbhum District কুসাপা (রাজবংশি ভাষায়)

• Burmese – ငန်းတော်ကျား ngān taw kyā
• Hindi – ahiraaj saamp
• Indonesian – welang
• Ho – Sakombiń
• Malayalam – manjavarayan (മഞ്ഞവരയൻ)
• Marathi – patteri manyar, पट्टेरी मण्यार agya manyar, sataranjya
• Odia – rana (ରଣା)
• Tamil – kattu viriyan (கட்டுவிரியன்), yennai viriyan, yettadi viriyan
• Telugu – katla paamu (కట్ల పాము) or bangaru paamu (బంగారు పాము) meaning the golden snake
• Tulu – kadambale