The Adder is Latvia’s only venomous snake. You may meet this snake in early spring when ground is still frozen. This one is male adder. Males usually are blue-grey but females are brown, but at some places  more than a half are almost black.  The Adder is phyletic new species, this is way sometimes you may see adder in very different colours, for example, half of the snake is light while other is dark. The adder warn for their presence loudly hissing. It is not advisable to tease this snake as it need strenght for mating that take place in spring. You have to remember that adder is not willing to bite everyone that cross its path because they have to use a lot of energy to create the venom and it takes several days to renew it.