Adders are one of three species of native snakes which can be found in woodlands and heathland across the UK.
They are venomous, meaning they inject toxins through their bite.
Males adders usually have a silver or grey colouration and females can be copper or brown but both have a distinctive black zig-zag pattern along their backs.
Adders are the only venomous snake in the UK (Image: Keith Sowter)
However, fully black adders have been spotted in some areas, including at RSPB Minsmere near Leiston.
Keith Sowter was walking around the nature reserve and captured an image of the uncommon snake.
He said black adders have been sighted at the reserve as recently as Friday, March 6.
Adders hibernate through the coldest part of the year from October to March and sleep in sheltered and dry spots.
At the start of spring, when the weather begins to warm up, adders wake up from their hibernation and can be found basking in the sunlight.