I watched this pair of large (5-6 feet) male black snakes for about 20 minutes. They were near our top dam, totally absorbed in their own business and let me approach to within 2 metres without taking the slightest notice.
They would twine together like this (photo 2) in fractions of a second and untwine as quickly. They did not appear to be biting, but vigorously vying for dominance. Placing your head on top of the other chaps seemed to be considered a good move.
I confess that I originally thought this was mating behaviour. I then consulted Richard Shine's excellent book "Australian Snakes - A natural history". He is clear that this sinuous muscular dance is male wrestling. During mating the female adopts a more passive role while the male movements are excited and jerky.
