Two of my enterprising young charges caught a large cockroach on the diamond mine grounds today. It was one of those large, sort of scary ones we usually call "waterbugs" around these parts. Very possibly it was the American cockroach, Periplaneta americana.
I gave the kids a small plastic container in which to keep their new pet. While scary-looking, the cockroach was also quite fascinating. It was about 1 to 1.25 inches in length (about 3 cm). Its legs were covered with interesting barbs or spines, and the ends of these legs had little hooks on it. The antennae were long and mobile.
I was asked about what they eat. Apparently, they're not very picky - consuming just about everything. Essentially they are scavengers, cleaning up crumbs, food wastes, dead leaves, whatever.
And they have been found to harbor a number of disease-causing pathogens, so I wouldn't advise handling one, or at least remember to wash your hands when you do.