Melanistic adder - Devon

Here's one from London which I saw today while doing pre-hibernation surveys:

Hi Mark; yes, great animal which had just shed, giving a blueish tinge to the scales.  I was thinking the same thing when I found it, ie that there's a gradation from almost jet black, with no white supralabial scales at all, and no hint of a zig-zag through to what are basically just rather dark 'normal' animals.  I guess the genetics (and environmental effects) of melanism must be very complicated, and not simply a question of a single recessive allele.

Thanks for sharing

that stunning!!