The tail is another storage area which should also bulge a bit when the lizard is fat . Food is the main thing governing these two areas but water can also play a part. If water is not available for a couple of weeks or it has diarrhoea the BT will look very skinny in the body and legs but can regain this bulk almost overnight after a good drink . The others can be enticed to eat such things but the Blue Tongue doesn't seem to care about it's dinners life status and movement is optional. Adult Blue Tongues are easily sexed by comparing their head size.
Males have a much broader head than females of a similar size.
Mating occurs in early Spring following Winter cooling. Separating a breeding pair prior to Winter seems to help initiate a more immediate response when they are placed back together in the Spring. She was successfully mated to a large male at the end of November last year and we are still waiting for the babies. Copulation was observed several times over a fortnight. This was a big turn around from the actual mating period where the male actually drew blood.