Grass snakes are not poisonous. Although they may hiss and strike out if disturbed, they are completely harmless to man.
They are olive green with dark spots on the sides and back, white and black scales on the belly, and a cream or yellow collar. It is the largest British snake usually measuring about 4 feet long.
Grass snakes mainly live in woodland but can often be found in parks or gardens. They can sometimes be seen lying in water on very sunny days. They are the most common snakes seen in British gardens and feed mainly on frogs, toads and fish.
Grass snakes hibernate in the autumn, and do not appear until spring. After mating in May, the females lay their eggs in June or July. They lay their eggs in warm, moist, rotting vegetation, such as garden compost heaps.