极北蝰种

特征

体长一般为55 cm（22英寸），不同地区的个体大小也不同。最大的个体发现于斯堪的纳维亚，长90 cm（35英寸）。其体重在50—180克（1.8—6.3盎司）之间。

毒性

它是欧洲常见的毒蛇，每年都有人畜被咬案例。光瑞典每年就有约1,300人被咬，其中约12%需要就医。现有至少八种可用于治疗其咬伤的抗蛇毒素。

相比其他蝰蛇来说，极北蝰的毒性并不强。其小鼠半数致死剂量为0.55 mg/kg（静脉注射）、0.80 mg/kg（腹膜内注射）和6.45 mg/kg（皮下注射）。对人类来说，其咬伤一般并非特别致命。就英国而言，自1876年以来全英只有14人死于极北蝰蛇毒。

保护

包括挪威、丹麦和英国在内的部分欧洲国家禁止捕杀、伤害或交易极北蝰，瑞士也把它列为濒危物种。但它本身为IUCN无危物种。

Vipera berus, commonly known as the common European adder and the common European viper, is a species of venomous snake in the family Viperidae. The species is extremely widespread, and thus can be found throughout much of Europe, and as far as East Asia. There are three recognised subspecies.

Known by a host of common names including common adder and common viper, the adder has been the subject of much folklore in Britain and other European countries. It is not regarded as especially dangerous; the snake is not aggressive and usually bites only when really provoked, stepped on, or picked up. Bites can be very painful, but are rarely fatal. The specific name, berus, is Neo-Latin and was at one time used to refer to a snake, possibly the grass snake, Natrix natrix.

The common adder is found in different terrains, habitat complexity being essential for different aspects of its behaviour. It feeds on small mammals, birds, lizards, and amphibians, and in some cases on spiders, worms, and insects. The common adder, like most other vipers, is ovoviviparous, giving birth to live young. Females breed once every two or three years and litters are usually born in late summer to early autumn in the Northern Hemisphere. Litters range in size from three to 20 with young staying with their mothers for a few days. Adults grow to a total length (including tail) of 60 to 90 cm (24 to 35 in) and a mass of 50 to 180 g (1.8 to 6.3 oz). Three subspecies are recognised, including the nominate subspecies, Vipera berus berus, described here. The snake is not considered to be threatened, though it is protected in some countries.