Yep they enjoy a bit of live hunting here and there. Mealworms can be a fun treat for them as well as tiny live feeder goldfish. I haven't given mine a goldfish hunt in years since even though they seemed to get a kick out of it, it made a huge mess of their home with water and fish bits everywhere! I know someone that puts some live crickets into an empty toilet paper tube, bends down the ends and puts it in with the rats. Apparently they have a great time chewing into the tube to get their live treat out. A good mental and physical stimulation for them I would think.

Another great treat on a hot day is frozen green peas. Just put a small bowl of them in with the rats. It's basically rattie icecream.