Adders occupy one of the largest natural ranges of any venomous snake. Adders can be found from the United Kingdom to the Pacific coast of Asia. They are found as far north as the Arctic Circle and as far south as the Mediterranean Sea.
Biogeographic Regions: palearctic (Native ); oriental (Native )
Distribution: Norway, Sweden, Finland, France, Denmark, Germany, Austria, Switzerland, N Italy, Belgium, Netherlands, Great Britain, Poland, Czech Republic (formerly Czechoslovakia), Hungary, Romania, Belarus, Turkey, Bulgaria, Albania, Yugoslavia: Croatia, Slovenia, Macedonia, Bosnia-Hercegowina, Monte Negro, Macedonia, Serbia, Estonia, Latvia, Lithuania, Russia, Mongolia, North Korea, NW China (N Xinjiang, Jilin) bosniensis: Bosnia, Croatia, Serbia, Macedonia, Montenegro, N Albania, N Greece, Hungary sachalinensis: E Russia (Sachalin Island and adjacent mainland)
Type locality: Uppsala, Sweden
Adders begin life approximately 16-18 cm long and can grow as long as 80 cm. The mass of male adders generally ranges from 50 to 70 grams, while the mass of females ranges from 80 to 100 grams. Mature adders may be a variety of colors. In general, male adders are grey, cream, whitish, or pale-yellow, with a distinct dark pattern on their backs and sides. This pattern can be described as zig-zag or a series of contiguous “X”s. The sides of Vipera lotievi often have a broken zig-zag pattern. Adders have a distinctive superorbital scale pattern, the scales extend over their eyes, giving them a lidded appearance. Vipera lotievi has a recognizable dark colored “V” on its head, the point of which can be found between its eyes. Female adders have the same distinct patterns along their backs and heads, but their coloring is slightly different. Females are usually reddish in color with brown-toned markings. Juvenile adders are also generally reddish. Occasionally, adders can be completely melanistic.
Adders, like other members of Viperidae, have hinged fangs used to inject venom into their prey. Hinged fangs fold at the base to lie against the roof of the mouth. This feature enables these fangs to grow quite large in comparison to those belonging to snakes without hinged fangs.
Range mass: 50 to 100 g.
Range length: 16 to 80 cm.
Average length: 60 cm.
Other Physical Features: heterothermic ; venomous
Sexual Dimorphism: female larger; sexes colored or patterned differently
Adders can live in woodlands, moorlands, heathlands, and wetlands. Open, sunny glades and/or slopes suitable for sunning are important components of preferred habitats. It is also crucial that there is relatively dense ground cover available for adders to find shelter. Adders can survive in cold grasslands found in the northernmost areas of its range.
Range elevation: 0 to 1540 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest
Adders are carnivorous and consume a variety of prey, including small mammals such as voles (Arvicolinae), shrews (Soricidae), and mice (Murinae), as well as small lizards, birds, and frogs. There are two predatory techniques generally utilized by Vipera lotievi. The first is called the “sit and wait”, or ambush, technique. Adders wait in one place for prey to pass by so they can strike out, using fangs to inject their prey with enough venom to be fatal. Their keen sense of smell is then used to follow the wounded animal to its death where Vipera lotievi will proceed to consume the animal head first. The second technique involves actively seeking out prey. Adders generally use this technique when they are most active. Being a crepuscular creature these hours are usually right around dusk.
Animal Foods: birds; mammals; amphibians; reptiles
Primary Diet: carnivore (Eats terrestrial vertebrates)
One of the important roles played by Vipera lotievi is controlling the populations of small mammals, particularly rodents. Adders also contribute to the control of small bird, frog, and lizard populations. In addition, adders provide a source of food for larger mammals and birds.
There are several major predators that may prey on Vipera lotievi, both vertebrates and invertebrates. The most prominent vertebrate predators include foxes, Eurasian badgers, large diurnal birds of prey, and owls. Adders can also be preyed upon by larger snakes. Adders are cryptically colored, which protects them from many predators, and they can defend themselves with their venomous bites.
- foxes (Vulpes
- Eurasian badgers (Meles meles)
- diurnal birds of prey (Falconiformes)
- owls (Strigiformes)
- snakes (Serpentes)
Anti-predator Adaptations: cryptic
Life History and Behavior
There are several important senses utilized by Vipera lotievi in perceiving the environment and communicating between individuals. Adders have well-developed eyesight, which is valuable for hunting as well as general perception of the surrounding environment. In addition to sight, adders can hear, although they lack an outer ear. Instead, they detect sound through a mechanism called "skin-muscle-bone" route. Sound waves hit the skin of the adder and the vibrations are transfered through the jaw muscles and the several bones until they reach the snake's inner ear. Adders also have a well-developed sense of smell. They smell using both the tongue and nostrils. As Vipera lotievi flicks its tongue in and out of its mouth, the tongue is actually picking up tiny particles and molecules and transfering these to small openings on the roof of its mouth which lead to the olfactory center where the particulate matter will be identified as having a specific smell. These highly-developed senses combine to make Vipera lotievi individuals very effective predators.
Communication between adders is very important during mating season. The sense of smell plays an especially important role in mating, particularly in finding an appropriate mate. In general, snakes emit pheromones that can be sensed by other snakes. Pheromones are key chemical indicators in reproduction. Pheromones can indicate whether a female is sexually ready to reproduce. Pheromones can linger in the air long after a snake has occupied a given area, which further aids in communication between individuals over longer distances. As pheromones are chemical indicators, snakes sense pheromones using chemical receptors such as taste and/or smell.
Communication Channels: visual ; tactile ; chemical
Other Communication Modes: pheromones
Perception Channels: visual ; tactile ; acoustic ; chemical
Adders are viviparous. Adder eggs are fertilized internally during copulation.
Adders have a fairly long lifespan. They generally live for 10 to 15 years in the wild. There are reports that claim adders have reached 25 years of age. Little information is available describing the lifespans of captive adders. This may stem from the fact that adders are neither desirable as pets, nor particularly endangered, thus few are kept in captivity.
Status: wild: 25 (high) years.
Status: wild: 15 (high) years.
Status: wild: 10 years.
Status: captivity: 2.1 years.
Lifespan, longevity, and ageing
Adders mate seasonally in the spring, usually April, soon after emerging from hibernation. The males emerge first and stay close to the hibernation site in an area referred to as the mating ground. As females emerge, males swarm around them and allow females to choose a mate with whom to copulate. Male adders can also locate sexually receptive females using their keen sense of smell. After locating a receptive mate, copulation occurs. Males generally remain with the female for several hours after mating. During this time, the male will fight any other males who attempt to court his mate. When two adders fight, both raise their bodies into the air and intertwine themselves in an attempt to wrestle one another to the ground. This method of fighting is known as the "dance of the adders". After several hours of remaining with his mate, the male leaves to find another mate.
There are several notable courtship rituals that occur before mating between a male and female. These rituals include tongue flicking, tail vibrations, and body quivering. When two males try to court the same female, fighting can occur during which males raise the upper half of their bodies off the ground and attempt to wrestle each other to the ground. More than two males can be involved in these fights.
Mating System: polygynous
April is the most common month during which adders reproduce. Their gestation period ranges from three to four months, so young live adders are born during the fall months, generally during hibernation. Female adders usually give birth to approximately 12 live young. Three to four years following birth, these young adders will be ready to mate with other adders.
The gestation period is approximately 3 to 4 months. Young adders are often born slightly before or during hibernation in those populations that hibernate. The young are born with fat reserves to aid them in survival until the end of hibernation. They also have access to a yolk sac, which is full of nutrients necessary for survival. At birth, Vipera lotievi individuals measure approximately 16 to 18 cm long. Young adders will not become sexually mature for 3 to 4 years.
Breeding interval: Adders breed once a year in the spring.
Breeding season: Copulation between adders occurs in early spring, generally during the month of April. Young adders are generally born in the fall, generally during hibernation.
Average number of offspring: 12.
Range gestation period: 3 to 4 months.
Average time to independence: 3 hours.
Range age at sexual or reproductive maturity (female): 3 to 4 years.
Range age at sexual or reproductive maturity (male): 3 to 4 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; viviparous
It is not well known how long young Vipera lotievi remain with their mothers. The offspring of other species of viviparous vipers have been known to remain with the mother for several hours after birth before dispersing. Young vipers are independent soon after birth.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female)
Molecular Biology and Genetics
Statistics of barcoding coverage: Vipera berus berus
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1
Adders are a protected species in some countries, Britain being one example. Their reputation as venomous has been quite detrimental to conservation efforts. People have been inclined to kill adders regardless of their conservation status because of their fear of these animals. Adders also suffer from loss of habitat, mostly due to human activities such as development and agriculture. Deforestation and scrub encroachment on preferred habitats also negatively impacts adders.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: no special status
Relevance to Humans and Ecosystems
Adders are venomous snakes and their bites are dangerous to humans. While adder bites are rarely fatal, they do require immediate medical treatment and are very painful. Adders can kill small animals like dogs and cats if they feel threatened. Pets should therefore be closely watched in areas where adders occur.
Negative Impacts: injures humans (bites or stings, venomous )
Adders play a key role in controlling populations of rodents and other small animals that are sometimes considered pests. Adders can also be milked to collect their venom, which can then be used to produce anti-venom for the treatment of adder bites.
Positive Impacts: source of medicine or drug ; controls pest population
Vipera berus, the common European adder or common European viper, is a venomous viper species that is extremely widespread and can be found throughout most of Western Europe and as far as East Asia. Known by a host of common names including common adder and common viper, adders have been the subject of much folklore in Britain and other European countries. They are not regarded as especially dangerous; the snake is not aggressive and usually bites only when alarmed or disturbed. Bites can be very painful, but are seldom fatal. The specific name, berus, is New 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. Females breed once every two or three years, with litters usually being 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 recognized, including the nominate subspecies, Vipera berus berus described here. The snake is not considered to be threatened, though it is protected in some countries.
The name "adder" is derived from nædre an Old English word that had the generic meaning of serpent in the older forms of many Germanic languages. It was commonly used in the Old English version of the Christian Scriptures for the devil and the serpent in the Book of Genesis. In the 14th century, "a nadder" in Middle English was rebracketed to "an adder" (just as "a napron" became "an apron" and "a nompere" changed into "an umpire").
In keeping with its wide distribution and familiarity through the ages, Vipera berus has a large number of common names in English, which include:
- Common European adder, common European viper, European viper, northern viper, adder, common adder, crossed viper, European adder, common viper, European common viper, cross adder, or common cross adder.
In Sweden, Norway, and Denmark, the snake is known as huggorm or hoggorm, roughly translated as "striking serpent" or "cutting serpent". In Finland, it is known as kyykäärme or simply kyy, in Estonia it is known as rästik, while in Lithuania it is known as angis.
Relatively thick-bodied, adults usually grow to 60 cm (24 in) in total length (including tail), with an average of 55 cm (22 in). Maximum size varies by region. The largest, at over 90 cm (35 in), are found in Scandinavia; specimens of 104 cm (41 in) have been observed there on two occasions. In France and Great Britain, the maximum size is 80–87 cm (31–34 in). Mass ranges from 50 g (1.8 oz) to about 180 grams (6.3 oz).
The head is fairly large and distinct and its sides are almost flat and vertical. The edge of the snout is usually raised into a low ridge. Seen from above, the rostral scale is not visible, or only just. Immediately behind the rostral, there are two (rarely one) small scales. Dorsally, there are usually five large plates: a squarish frontal (longer than wide, sometimes rectangular), two parietals (sometimes with a tiny scale between the frontal and the parietals), and two long and narrow supraoculars. The latter are large and distinct, each separated from the frontal by one to four small scales. The nostril is situated in a shallow depression within a large nasal scale. The eye is relatively large—equal in size or slightly larger than the nasal scale—but often smaller in females. Below the supraoculars are six to 13 (usually eight to 10) small circumorbital scales. The temporal scales are smooth (rarely weakly keeled). There are 10–12 sublabials and six to 10 (usually eight or 9) supralabials. Of the latter, the numbers 3 and 4 are the largest, while 4 and 5 (rarely 3 and 4) are separated from the eye by a single row of small scales (sometimes two rows in alpine specimens).
Midbody there are 21 dorsal scales rows (rarely 19, 20, 22, or 23). These are strongly keeled scales, except for those bordering the ventral scales. These scales seem loosely attached to the skin and lower rows become increasingly wide; those closest to the ventral scales are twice as wide as the ones along the midline. The ventral scales number 132-150 in males and 132–158 in females. The anal plate is single. The subcaudals are paired, numbering 32–46 in males and 23–38 in females.
The colour pattern varies, ranging from very light-coloured specimens with small, incomplete, dark dorsal crossbars to entirely brown ones with faint or clear, darker brown markings, and on to melanistic individuals that are entirely dark and lack any apparent dorsal pattern. However, most have some kind of zigzag dorsal pattern down the entire length of their bodies and tails. The head usually has a distinctive dark V or X on the back. A dark streak runs from the eye to the neck and continues as a longitudinal series of spots along the flanks. Unusual for snakes, the sexes are possible to tell apart by the colour. Females are usually brownish in hue with dark-brown markings, the males are pure grey with black markings. The basal colour of males will often be slightly lighter than that of the females, making the black zigzag pattern stand out. The melanistic individuals are often females.
Vipera berus has a wide range. It can be found across the Eurasian land-mass; from northwestern Europe (Great Britain, Scandinavia, Germany, France) across southern Europe (Italy, Serbia, Albania, Croatia, Montenegro, Bosnia and Herzegovina, Republic of Macedonia, Bulgaria, and northern Greece) and eastern Europe to north of the Arctic Circle, and Russia to the Pacific Ocean, Sakhalin Island, North Korea, northern Mongolia and northern China. The type locality was originally listed as "Europa". Mertens and Müller (1940) proposed restricting the type locality to "Upsala, Schweden" (Uppsala, Sweden) and it was eventually restricted to Berthåga, Uppsala by designation of a neotype by Krecsák & Wahlgren (2008).
In several European countries, it is notable as being the only native venomous snake.
In the United Kingdom, it is illegal to kill, injure, harm, or sell adders under the 1981 Wildlife and Countryside Act. The common viper is categorised as "endangered" in Switzerland, and is also protected in some other countries in its range. It is also found in many protected areas. This species is listed as protected (Appendix III) under the Berne Convention.
The International Union for the Conservation of Nature Red List of Threatened Species describes the conservation status as of "least concern" in view of its wide distribution, presumed large population, broad range of habitats, and likely slow rate of decline though it acknowledges the population to be decreasing. Reduction in habitat for a variety of reasons, fragmentation of populations in Europe due to intense agriculture practices, and collection for the pet trade or for venom extraction have been recorded as major contributing factors for its decline.
Sufficient habitat complexity is a crucial requirement for the presence of this species, in order to support their various behaviors—basking, foraging, and hibernation—as well as to offer some protection from predators and human harassment. It is found in variety of habitats, including: chalky downs, rocky hillsides, moors, sandy heaths, meadows, rough commons, edges of woods, sunny glades and clearings, bushy slopes and hedgerows, dumps, coastal dunes, and stone quarries. They will venture into wetlands if dry ground is available nearby and thus may be found on the banks of streams, lakes, and ponds.
In much of southern Europe, such as southern France and northern Italy, it is found in either low lying wetlands or at high altitudes. In the Swiss Alps, it may ascend to about 3,000 m (9,842 ft). In Hungary and Russia, it avoids open steppeland; a habitat in which V. ursinii is more likely to occur. In Russia, however, it does occur in the forest steppe zone.
This species is mainly diurnal, especially in the north of its range. Further south it is said to be active in the evening, and it may even be active at night during the summer months. It is predominantly a terrestrial species, although it has been known to climb up banks and into low bushes in order to bask or search for prey.
Adders are not usually aggressive, tending to be rather timid and biting only when cornered or alarmed. People are generally bitten only after stepping on them or attempting to pick them up. They will usually disappear into the undergrowth at a hint of any danger, but will return once all is quiet, often to the same spot. Occasionally, individual snakes will reveal their presence with a loud and sustained hissing, hoping to warn off potential aggressors. Often, these turn out to be pregnant females. When the adder is threatened, the front part of the body is drawn into an S-shape to prepare for a strike.
The species is cold-adapted and hibernates in the winter. In Great Britain, males and females hibernate for about 150 and 180 days respectively. In northern Sweden hibernation lasts 8–9 months. On mild winter days, they may emerge to bask where the snow has melted and will often travel across snow. About 15% of adults and 30–40% of juveniles die during hibernation.
Diet consists mainly of small mammals, such as mice, voles, and shrews, as well as lizards. Sometimes, slow worms are taken, and even weasels and moles. They feed on amphibians, such as frogs, newts, and salamanders. Birds are also reported to be on the menu, especially nestlings and even eggs, for which they will climb into shrubbery and bushes. Generally, diet varies depending on locality. Juveniles will eat nestling mammals, small lizards and frogs as well as worms and spiders. Once they reach about 30 cm (1 ft) in length, their diet begins to resemble that of the adults.
In Hungary, mating takes place in the last week of April, while in the north it happens later in the second week of May. Matings have also been observed in June and even early October, but it is not known if the autumn matings result in any young. Females often breed once every two years, or even once every three years if the seasons are short and the climate is severe.
Males find females by following their scent trails, sometimes tracking them for hundreds of meters a day. If a female is found and flees, the male follows. Courtship involves side-by-side parallel "flowing" behavior, tongue flicking along the back and excited lashing of the tail. Pairs stay together for one or two days after mating. Males chase away their rivals and engage in combat. Often, this also starts with the aforementioned flowing behavior before culminating in the dramatic "adder dance." In this act, the males confront each other, raise up the front part of the body vertically, make swaying movements and attempt to push each other to the ground. This is repeated until one of the two becomes exhausted and crawls off to find another mate. Interestingly, Appleby (1971) notes that he has never seen an intruder win one of these contests, as if the frustrated defender is so aroused by courtship that he refuses to lose his chance to mate. There are no records of any biting taking place during these bouts.
Females usually give birth in August or September, but sometimes as early as July, or as late as early October. Litters range in size from 3 to 20. The young are usually born encased in a transparent sac from which they must free themselves. Sometimes, they succeed in freeing themselves from this membrane while still inside the female. The neonates measure 14 to 23 centimetres (5.5 to 9.1 in) in total length (including tail), with an average total length of 17 cm (6.7 in). They are born with a fully functional venom apparatus and a reserve supply of yolk within their bodies. They shed their skins for the first time within a day or two. Females do not appear to take much interest in their offspring, but the young have been observed to remain near their mothers for several days after birth.
Because of the rapid rate of human expansion throughout the range of this species, bites are relatively common. Domestic animals and livestock are frequent victims. In Great Britain, most instances occur in March–October. In Sweden, there are about 1,300 bites a year, with an estimated 12% that require hospitalisation. At least eight different antivenoms are available against bites from this species.
Mallow et al. (2003) describe the venom toxicity as being relatively low compared to other viper species. They cite Minton (1974) who reported the LD50 values for mice to be 0.55 mg/kg IV, 0.80 mg/kg IP and 6.45 mg/kg SC. As a comparison, in one test the minimum lethal dose of for a guinea pig was 40–67 mg, but only 1.7 mg was necessary when Daboia russelii venom was used. Brown (1973) gives a higher subcutaneous LD50 range of 1.0–4.0 mg/kg. All agree that the venom yield is low: Minton (1974) mentions 10–18 mg for specimens 48–62 cm (19–24 in) in length, while Brown (1973) lists only 6 mg.
Relatively speaking, bites from this species are not highly dangerous. In Britain there have been only 14 known fatalities since 1876; the last a 5-year-old child in 1975. and one near fatal bite of a 39 year old woman in Essex in 1998. An 82-year-old woman died following a bite in Germany in 2004, although it is not clear whether her death was due to the effect of the venom. Even so, professional medical help should always be sought as soon as possible after any bite. Very occasionally bites can be life-threatening, particularly in small children, while adults may experience discomfort and disability long after the bite. The length of recovery varies, but may take up to a year.
Local symptoms include immediate and intense pain, followed after a few minutes (but perhaps by as much as 30 minutes) by swelling and a tingling sensation. Blisters containing blood are not common. The pain may spread within a few hours, along with tenderness and inflammation. Reddish lymphangitic lines and bruising may appear, and the whole limb can become swollen and bruised within 24 hours. Swelling may also spread to the trunk, and with children, throughout the entire body. Necrosis and intracompartmental syndromes are very rare.
Systemic symptoms resulting from anaphylaxis can be dramatic. These may appear within 5 minutes post bite, or can be delayed for many hours. Such symptoms include nausea, retching and vomiting, abdominal colic and diarrhoea, incontinence of urine and faeces, sweating, fever, vasoconstriction, tachycardia, lightheadedness, loss of consciousness, blindness, shock, angioedema of the face, lips, gums, tongue, throat and epiglotis, urticaria and bronchospam. If left untreated, these symptoms may persist or fluctuate for up to 48 hours. In severe cases, cardiovascular failure may occur.
The species has three recognised subspecies :
|Subspecies||Taxon author||Common name||Geographic range|
|V. b. berus||(Linnaeus, 1758)||Common European adder||Norway, Sweden, Finland, Latvia, Estonia, Lithuania, France, Denmark, Germany, Austria, Switzerland, Northern Italy, Belgium, Netherlands, Great Britain, Poland, Czech Republic, Slovakia, Hungary, Romania, Russia, Mongolia, Northwest China (north Xinjiang)|
|V. b. bosniensis||Boettger, 1889||Balkan cross adder||Balkan Peninsula|
|V. b. sachalinensis||Zarevskij, 1917||Sakhalin Island adder||Russian Far East (Amur Oblast, Primorskye Kray, Khabarovsk Kray, Sakhalin Island), North Korea, Northeast China (Jilin)|
The subspecies V. b. bosniensis and V. b. sachalinensis have been regarded as full species in some recent publications.
- List of viperine species and subspecies
- Viperinae by common name
- Viperinae by taxonomic synonyms
- List of reptiles of Italy
- Isailovic, Jelka Crnobrnja, et al. (2009). Vipera berus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2.
- McDiarmid RW, Campbell JA, Touré T. (1999). Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1. Washington, District of Columbia: Herpetologists' League. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- Mallow D, Ludwig D, Nilson G. (2003). True Vipers: Natural History and Toxinology of Old World Vipers. Malabar, Florida: Krieger Publishing Company. ISBN 0-89464-877-2.
- Stidworthy J. (1974). Snakes of the World. New York: Grosset & Dunlap Inc. 160 pp. ISBN 0-448-11856-4.
- "Everyday Adders – the Adder in Folklore". The Herpetological Conservation Trust. Retrieved 7 February 2010.
- Warrell DA (2005). "Treatment of bites by adders and exotic venomous snakes". British Medical Journal 331 (7527): 1244–1247. doi:10.1136/bmj.331.7527.1244. PMC 1289323. PMID 16308385.
- Gotch AF. (1986). Reptiles: Their Latin Names Explained. Poole, UK: Blandford Press. 176 pp. ISBN 0-7137-1704-1.
- "Vipera berus". Integrated Taxonomic Information System. Retrieved 15 August 2006.
- "adder". Dictionary.com Unabridged. Random House, Inc. Retrieved 7 February 2010.
- U.S. Navy. (1991). Poisonous Snakes of the World. United States Government. New York: Dover Publications Inc. 232 pp. ISBN 0-486-26629-X.
- Vipera berus at the Reptarium.cz Reptile Database. Accessed 21 November 2007.
- Mehrtens JM. (1987). Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. ISBN 0-8069-6460-X.
- Steward JW. (1971). The Snakes of Europe. Cranbury, New Jersey: Associated University Press (Fairleigh Dickinson University Press). 238 pp. LCCCN 77-163307. ISBN 0-8386-1023-4.
- Brown JH. (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. ISBN 0-398-02808-7.
- Olsson, M.; Madsen, T.; Shine, R. (1997). "Is sperm really so cheap? Costs of reproduction in male adders,Vipera berus". Proceedings of the Royal Society B: Biological Sciences 264 (1380): 455–459. doi:10.1098/rspb.1997.0065. JSTOR 50437. PMC 1688262. (includes chart showing range of male mass in one population)
- Strugariu, Alexandru; Zamfirescu, Ştefan R.; Gherghel, Iulian (2009). "First record of the adder (Vipera berus berus) in Argeş County (Southern Romania)". Biharean Biologist 3 (2): 164. (gives example masses of females).
- Krecsák L, Wahlgren R. (2008). "A survey of the Linnaean type material of Coluber berus, Coluber chersea and Coluber prester (Serpentes, Viperidae)". Journal of Natural History 42 (35–36): 2343. doi:10.1080/00222930802126888.
- "Adder (Vipera berus)". Arkive (Images of life on Earth). www.wildscreen.org.uk. Retrieved 7 February 2010.. This ref cites Beebee T, & Griffiths R. (2000) Amphibians and Reptiles: a Natural History of the British Herpetofauna. London: Harper Collins Publishers Ltd. as the source.
- Monney JC, Meyer A. (2005). Rote Liste der gefährdeten Reptilien der Schweiz. Hrsg. Bundesamt für Umwelt, Wald und Landschaft BUWAL, Bern und Koordinationsstelle für Amphibien- und Reptilienschutz der Schweiz, Bern. BUWAL-Reihe.
- Convention on the Conservation of European Wildlife and Natural Habitats, Appendix III at Council of Europe. Accessed 7 February 2010.
- "IV: The Categories". 2001 IUCN Red List Categories and Criteria version 3.1. www.iucnredlist.org. Retrieved 14 February 2010.
- Street D. (1979). The Reptiles of Northern and Central Europe. London: B.T. Batsford Ltd. 272 pp. ISBN 0-7134-1374-3.
- Boulenger GA. (1913). Snakes of Europe. London: Methuen & Co. xi + 269 pp. (Vipera berus, pp. 230-239, Figure 35).
- Leighton, Gerald R. (1901). The Life-History of British Serpents and Their Local Distribution in the British Isles. Edinburgh & London: Blackwood & Sons. p. 84. ISBN 1-4446-3091-1. Retrieved 8 February 2010.
- Appleby LG. (1971). British Snakes. London: J. Baker. 150 pp. ISBN 0-212-98393-8.
- Vipera berus antivenoms at Munich Antivenom Index. Accessed 15 September 2006.
- Tod durch Kreuzotterbiss? at Gemeinsames Giftinformationszentrum. A 44 year old man was left seriously injured aye he was bitten by an Adder at the Go-Ape adventure park in Dalby, Burgh Yorkshire UK. Accessed 25 May 2007.
- Macrae, Fiona (21 July 2010) Adder bite leaves father blinded, choking and just minutes from death on walk with family. The Daily Mail, retrieved on 21 July 2010.
- Ananjeva NB, Borkin LJ, Darevsky IS, Orlov NL. 1998. [Amphibians and Reptiles. Encyclopedia of Nature of Russia]. Moscow: ABF. (in Russian).
- Arnold EN, Burton JA. 1978. A Field Guide to the Reptiles and Amphibians of Britain and Europe. London: Collins. 272 pp. ISBN 0-00-219318-3. (Vipera berus, pp. 217–218 + Plate 39 + Map 122).
- Boulenger GA. 1896. Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the...Viperidæ. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xiv + 727 pp. + Plates I.- XXV. (Vipera berus, pp. 476–481).
- Goin CJ, Goin OB, Zug GR. 1978. Introduction to Herpetology: Third Edition. San Francisco: W.H. Freeman. xi + 378 pp. ISBN 0-7167-0020-4. (Vipera berus, pp. 122, 188, 334).
- Jan G, Sordelli F. 1874. Iconographie générale des Ophidiens: Quarante-cinquième Livraison. Paris: Baillière. Index + Plates I.- VI. (Vipera berus, Plate II, Figure 1; var. prester, Plate II, Figures 2-4; var. concolor, Plate II, Figure 5; var. lymnaea, Plate II, Figure 6).
- Joger U, Lenk P, Baran I, Böhme W, Ziegler T, Heidrich P, Wink M. 1997. The phylogenetic position of Vipera barani and of Vipera nikolskii within the Vipera berus complex. Herpetologica Bonnensis 185-194.
- Linnaeus C. 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, diferentiis, synonymis, locis. Tomus I. Editio Decima, Reformata. Stockholm: L. Salvius. 824 pp. (Coluber berus, p. 217).
- Minton SA Jr. 1974. Venom Diseases. Springfield, Illinois: CC Thomas Publ. 256 pp. ISBN 978-0-398-03051-3.
- Morris PA. 1948. Boy's Book of Snakes: How to Recognize and Understand Them. A volume of the Humanizing Science Series, edited by Jacques Cattell. New York: Ronald Press. viii + 185 pp. (The common viper, Vipera berus, pp. 154–155, 182).
- Wüster W, Allum CSE, Bjargardottir IB, Bailey KL, Dawson KJ, Guenioui J, Lewis J, McGurk J, Moore AG, Niskanen M, Pollard CP. 2004. Do aposematism and Batesian mimicry require bright colours? A test, using European viper markings. Proceedings of the Royal Society of London B 271: 2495–2499. PDF at Wolfgang Wüster, School of Biological Sciences, University of Wales, Bangor. Accessed on 15 August 2006.
EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.
To request an improvement, please leave a comment on the page. Thank you!