At a site that has been very reliable for adders for over 30 years I filmed this large male sneaking away from me, as adders tend to do.
In August 2012 I managed to get a much better video at Thorncombe Woods.
That one was actually a very small male, it just looked big in the video.
Females are larger and browner, like this captive one at the British Wildlife Centre in Surrey.
As well as being smaller most male adders are more strikingly marked in black and grey,
like one at the British Wildlife Centre again.