Can adders and grass snakes occupy the same territory? Or will they attack each other if they do come across each other?

You would think the adder would win in any sort of fight between the two, but I wondered as they both have similar diets of small mammals and ampibians if they would behave territorially.

That's a very interesting question. I've never heard/seen an adder and a grass snake anywhere near each other so I don't know, but I would think that unless there was overcrowding they would be able to accupy the same area.

I think that grass snakes specialise in living in wet places, whereas adders much prefer drier places. Also, grass snakes eat mostly amphibians, and adders eat mainly rodents.

Those two facts are what keep adders and grass snakes apart. So, if you see a snake in the water--it's a grass snake, and not likely to bite you.

Snakes on top of cliffs, and in heathlands--don't bother them, they could be adders.

Kingfisher