We visited Pearson Park Wildlife garden to watch the mating frogs. We sat next to a few males which vigorously defended their spot. The one on the top shot, the lovely male closest to us, shows how the male frogs' white throat stands out like a torch while they are calling, which probably helps females locate them. Also in this photo you can see the dark hardened pads next to the thumbs of the male. These are called "nuptial pads" and are thought to aid in the gripping of the female by the male. They might also be used for fighting, as the photo below shows
The male underneath is the "intruder", the resident gripped him hard, he didn't like it and moved away
He carried on calling every 30 seconds or so, a low, "prrrrr". I was very pleased with this shot which shows the ripples that calling causes in the water, and his inflated throat.
And here is a side view too