It was difficult to down rats but they were edible. I strongly recommend cooking them because raw they can carry several diseases. Snakes, of course, are eaten the world over and some varieties are delicious. Just chop off the head, skin the rest, cook, then eat what's left. Even poisonous varieties are edible.
Maggots are something else.
Once we were issued rotten fish loaded with maggots. Our English cook protested and wanted to scrape them off. Afraid that some of the fish would be lost, I insisted that he cook fish, maggots and all. We ate the results which were really quite good. In May 1951, every PW in camp was swollen like a balloon from severe beri-beri.