I had one RES and three cooters, all females housed together in a backyard pond. The RES was clearly the most aggressive food-wise. Throw in ten worms, and Agnes, the RES would get eight of them. The other three would have to struggle to get two or three among them. Agnes didn't even have to get "bitey" with the others. She'd just put a paw to their shoulders and spin them 180 degrees away from the food, and munch at her leisure. When she got eggbound and died two years ago (at 38 years old!) and I had to tell my son, he said, "Agnes? Damn, she was my favorite, she was SUCH a *****!".