Ray Hamilton wrote: Do other species coil together in this way, anyone got more photos please?
Vipera aspis and Vipera berus basking in physical contact in the Swiss mountains.
picture on page 162 in:
Hofer, U., Monney, J.-C., Dušej, G. (2001): Die Reptilien der Schweiz: Verbreitung, Lebensräume, Schutz / Les Reptiles de Suisse: Répartition, Habitats, Protection / I Rettili della Svizzera: Distribuzione, Habitat, Protezione. Birkhäuser, Basel, xi + 202 pages. ISBN: 3-7643-6245-6
http://www.seh-herpetology.org/node/57