My group are teenagers at 5 - 7 yrs old. This Winter indoors has been a remarkable one. I have one displaying the nest building; completely re-organizing the enclosure every few days. I come home from work and "ta-da", all of the ground cover is moved up into a hill, where she proudly sits. Anyway, what I find interesting is when I pick any of them up, they do the "croaking" sound. Not a cluck, but a croak. All of them. The only other species I've heard this same sound from is the P megacephalum. Which has me thinking.... Their visual appearance is similar, except for the tail. I had 3 Big Heads in the late 80's. I kept them all together. Bad mistake. Within 6 months I had one left. Only to find out they bitterly fight til death. They made the identical sound when handled. The Manouria are nothing like that towards one another though.. Just thinking out loud here.