In reply to girlymonkey:
A few years ago, after climbing 'Blank' on the South Slabs in Glen Rosa, with my father, I stopped for a swim in a pool on the walk out while Dad walked on.
After getting out and starting to dry off, I noticed that I had been swimming with a companion:
http://www.ootnaboot.scot/summer2015/20150610Swimming_Adder.jpg
It was cold and lethargic and caught going round and round in an eddy, apparently unable to get out, so I fished it out with a stick and placed it on a warm bit of granite. To start with, it wouldn't move, but as it warmed it started perking up, until it decided it wasn't too sure about me:
http://www.ootnaboot.scot/summer2015/20150610Basking_Adder.jpg
I'm glad it hadn't been so energetic while I was swimming with it!
I left it to its business and headed off to catch up with Dad and get the ferry home.