Cyclades blunt-nosed viper (Macrovipera schweizeri)

Also known as: Milos viper
Synonyms: Vipera lebetina schweizeri
GenusMacrovipera (1)
SizeAverage length: 60 – 70 cm (2)

Classified as Endangered on the IUCN Red List 2006 (1).

The Cyclades blunt-nosed viper is a venomous snake found only on four small islands off the coast of Greece (3). Body colouration ranges from a pale, ivory white through ochre colours to a dark grey, and the skin is patterned by transverse rows of blotchy dark stripes (4). This snake belongs to the large true vipers of the Viperidae family (3), and occasionally reaches lengths of up to 90 to 110 cm (4). Snakes of the Viperidae family typically have broad triangular-shaped heads and heavy bodies (5). They also have long hinged fangs through which they inject venom into their victims (5); the venom of the Cyclades blunt-nosed viper is very potent and dangerous (4).

Endemic to the islands of Milos, Kimolos, Polyaigos (Polinos) and Siphnos in the western Cyclades off the coast of Greece (2) (6). More than half of the species’ total population is found on western Milos (6).

Prefers regions of dry, stony or rocky terrain, often on valley slopes, with small and large bushes, drained river valleys and brooks (2) (4).

The Cyclades blunt-nosed viper is nocturnal from early summer until mid-September (2), and more diurnal during the rest of the year (4). Lizards and birds have been recorded in the diet in the wild, with juveniles feeding just on lizards and adults more on birds (2). These snakes also eat mice and insects in captivity, but no wild rodents are found in the western Cyclades (Milos, Kimolos, Polyaigos) (4). Although predominantly ground-dwelling, this snake will climb trees to ambush birds. Hunting takes place near water pools during spring and in trees during autumn, following the migratory cycle and changing habitats used by the birds throughout the year (2).

The female reproductive cycle is biennial, with mating activity seemingly concentrated around mid-May, although it may extend to mid-August (2). The species is oviparous (2), with approximately 10 to 12 eggs being laid per clutch in captivity (4). Little else is known about the behavioural ecology of this snake in the wild.

The Cyclades blunt-nosed viper has become seriously threatened as a result of habitat destruction, road mortality and removal by man. Two big quarries are in continuous operation on western Milos, which have considerably increased in size over the last 15 years and destroyed large areas of pristine habitat. Additionally, there are plans for more quarries on western Milos, which pose an extremely significant threat to this critically endangered species. Fires also cause habitat destruction, destroying the large bushes and trees in which the main prey, birds, are found. During the period of ‘reforestation’ after a fire, goat and sheep grazing can be highly destructive, preventing trees and large bushes from growing. At present, tourism does not threaten the snake’s habitat, but a new airport planned for Milos may increase tourism to a level that is damaging to viper habitats. The other islands appear to provide fairly pristine, untouched habitat, and the populations there are healthy, although a little smaller than on Milos (2).

Road kill also poses a very serious problem, with an estimated 300+ snakes killed each summer on western Milos. Recent years have also seen an increase in collection of the snake for the pet trade, and an established population of feral cats are also a possible danger to the snake on western Milos, particularly to the survival of newborns and subadults (2).

The Regional Development Agency of Cyclades is implementing a project called ‘Protection and Promotion of the Habitats and Species of the Milos Island Natura 2000 Area’, focussing on three main actions. Firstly, monitoring of the region’s habitats and species, including this viper, are to be ongoing. Secondly, efforts will be made to raise public awareness of the threats that face Milos’ flora and fauna, including promoting Milos Island as a destination of great ecological and ecotourism value (6). Not only could the dissemination of information help reduce intentional killing of the snake, but it could also help instil a sense of pride in the local fauna and encourage local inhabitants to support the police in their struggle against snake hunters (2). Finally, roads will be made safer for crossing vipers through the construction of barriers and underground passages. The Standing Committee of the Bern Convention has also recommended that there is stronger and stricter police control of illegal trade in the species (6). Further conservation actions advocated include the establishment of protected areas with optimal habitats and connective corridors, and the eradication of feral cats if studies verify the threat they pose to young snakes (2). A captive breeding programme has been started in collaboration with Jersey Zoo, and a similar programme has been proposed for Budapest Zoo and Botanical Gardens (3), which will provide an important buffer against extinction and offer potential for future reintroductions into the wild.

For more information on the Cyclades blunt-nosed viper see:

Nilson, G., Andren, C., Ioannidis, Y. & Dimaki, M. (1999) Ecology and conservation of the Milos viper, Macrovipera schweizeri (Werner, 1935). Amphibia-Reptilia, 20(4): 355 – 375. Available at:

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  1. IUCN Red List (December, 2009)