Thursday, 1 October 2009

Variable vipers

Rambling Rob recently posted a photograph of a beautifully coloured female adder (click here) which reminded me of the occcasion when my daughter nearly rode over this adder while cycling in the College Valley in the Cheviot hills. She thought it was a stick but when it suddenly moved she jammed on the brakes and managed to stop just in time. She got such a shock she adder viper brow. (groan...sorry).
The colour variation betweeen males and females is well documented (try here) but I also wonder if there is a geographical variation too? I admit that I have not seen that many adders but all that I have seen in Northumberland have been much darker than Rob's example.
Postscript: A monograph in the Shire Natural History series on the adder (by Peter Stafford) explains that infant and juvenile adders are much more brightly coloured and, particularly in females, can be a quite bright, orange or even reddish shade. In fact they are so differently coloured that at one time they were thought to be a different species - the dwarf red adder. It takes about 4 years to attain the final adult colouration and so there will be quite a broad variation in any population. Furthermore, the dark markings are very variable too. In some individuals the zig zag can even be replaced by a perfectly straight line of marks broken up into blotches.


  1. Thanks for the link Allan.

    I'm a fan of the Shire series, although I seem to have collected titles I never read - Scales & Balances, Ships' Figureheads, Old Handcarts...

    I think an Adder on the move looks like a GP's signature.

  2. Reading a message on the BBC's Autumnwatch message board, someone reported seeing black adders in Hampshire (blacker than a black thing, sire). The West Sussex and New Forest populations I've witnessed are the dark, reddish-brown with very dark zig-zags. Are black ones just a melanistic form, restricted to one locality or does each region have some?

  3. Hi Crumbling Cliff. I've never seen a black adder myself but according to the New Naturalist 'Reptiles and Amphibians in Britain' melanic adders may occur anywhere but seem to be relatively common in certain areas compared to others and in the New Forest and the Gower peninsula in particular.