In the upper jaw there is a pair of teeth, which at the base are connected to venom-glands. These are emptied when the viper bites.
The venom is potent and dangerous. It acts directly on the nervous system and affects the spinal cord. The effect of the venom depends on the viper's age, size and the quantity of the venom. If the glands have recently been emptied the injected dosage is almost ineffective.
It is lazy and listless in its movements and is thus not dangerous unless carelessly stepped upon or grabbed accidentally while picking flowers or herbs.
The color varies from grey to brown, olive-green or red, depending on its habitat - that is to say according to protectional needs imposed by the environment. This is why one might accidentally step on it without seeing it first. The most beautiful and characteristic Milos Viper is beyond any doubt the red viper.
In the middle of its back from head to tail runs a long, dark line made up of rhomboid spots, and on each side there is a double line of small, dark spots.
It feeds on live lizards, worms, snails, mice and rats. It eats them whole - which is why you may see it with a strangely inflated stomach at times - and it digests its prey little by little, taking a long time to do so. Collectors nowadays feed it only one frozen rat a month.
During winter it hibernates. It wakes up in spring and begins its active, reproductive cycle. Gestation lasts 8 months. It lays eggs (i.e. it is oviparous), which immediately hatch.
An endangered species
The greatest danger it faces today comes from vehicles. And as has always been the case it is being killed in agricultural areas, especially the irrigated ones, because it prefers shade and humidity.
Most suffer from the destruction of their natural habitat, mainly caused by deforestation due to agricultural expansion, mining activities and fires.
Until a few years ago, systematic collection and selling of live specimens, bought up by the pharmaceutical industry or by whoever produced antidotes from their venom, was all too common.
The last years this activity has become illegal and the Milos Viper has been declared an endangered species.
In line with the program Natura 2000, a large area of western Milos, in Chalakas, has been laid out for its protection in an attempt to save The Milos Viper from extinction.