Most people are happy to see the snow melt, But the warmer temperatures bring some unwelcome guests to Sweden. There are killer slugs, ticks that carry nasty diseases, and, not least the poisonous snake known as the viper.
Biologist Lars-Åke Janzon of the Swedish Museum of Natural History says viper season is here.
But not every snake in Sweden is a viper. Grass snakes are harmless.