Serum: Serum 54
Specie: Vipera berus
Common Name: Adder
General Body appearance: The best distinction between sexes is the shape of the tail, females have a relatively short tail, which narrows directly from cloaca to tail tip. Males do have a longer tail. From cloaca to tail tip, the tail first widens. This is caused by the to hemi penises, that are situated behind the cloaca.
THEY ARE VIVIPAROUS, the female gives birth to from 3 to 18 young measuring around 10 to 15 cm long. The Juvenile are like adults but smaller. Juveniles cannot yet control the amount of poison injected when biting and therefore a juveniles' bite can be as serious as an adults' bite The Adults vary enormously in colour and pattern. Typical males are greyish with a well defined blackish dorsal zigzag stripe. Typical females tend to be more brownish and their zigzag stripe is less well defined and darker brownish. Uniform colored specimens occur. Completely black or brick-red individuals have been reported
Venom: The Adder is the most widespread snakes in Europe, but serious accidents seldom occur. Its venom is powerful enough to kill a child or dog. Adult people will normally not be killed, however fatalities have been reported. They are front fanged like all vipers and their fangs can be put away by the snake, this means that the snake may bite without using their fangs. Adders are known to be able to control the amount of venom injected during a bite, thus avoiding waste of venom by overdoses
Size: They can grow up to 70 cm long, but often seen at from 40 to 50 cm long. Females tend to be slightly larger than males. They can live up to 10 years in the wild.
Diet: They eat mainly small mammals but also like lizards and other reptiles and birds, juveniles prefer to feed on lizards. Adults eat about 5 to 6 mice a year.
Habitat: In the lowlands Vipera berus is found mostly in heaths and moors, at more or less humid areas. Sometimes they are found in open bushy areas adjacent to a heath. In the Netherlands for instance more than 85% of the observations of Adders are recorded in vegetation consisting mainly of Molinia caerulea (Purple Moor-grass). In the mountains of Europe Vipera berus is found in open woodland, grasslands and damp meadows, mostly in relatively cool and not too dry places. Although Adders prefer basking in sunshine at low temperatures, they avoid excessive heat or dryness
Habits: Mainly diurnal, but may be nocturnal when weather conditions allows it to be. When they are disturbed they may stay quite calm and move away quite slowly. They are slow and docile, until trapped or cornered when they become very defensive biting rapidly. Best seen at relatively low temperatures, when they are basking to gain body heat. Optimal body temperature between 24 and 28 C. Air humidity seems an important factor in observing Adders: when the air is too dry they don't expose themselves to sunshine, but stay in the vegetation. Hibernation from mid October till mid March in dryer places underground. Mice and rabbit holes are often used for hibernation. Also holes under trees are used for this purpose. As soon as soil temperature rises above 10 C, they come out and expose themselves to sunshine. Males come out approximately 2 weeks earlier than females.
Reproduction: About a month after coming out of hibernation, males slough their skin and soon after they go looking for females which they track on scent. They follow a female as long as needed until she is willing to mate. In the northern part of their geographical distribution, females do not mate every year but every two years
Mating is done very prudent and may take them more than one hour. After mating males and females go their own way. If a male encounters another male when following a female to mate, the two will fight to determine which one is the strongest and may mate with the female. This fight is seldom observed, but is a marvellous spectacle. The 2 males raise their heads and the front part of their body like a cobra. Then they try to push each other aside, moving simultaneously and very elegantly. These fights never last long and ends when one of the two gives up
Useful Links:
http://www.reptilia-amphibia.net/index.html?en/snake/vipera-berus_adder-common-viper.html~mainFrame
http://www.arkive.org/species/ARK/reptiles/Vipera_berus/more_info.html
