Reptiles such as Snakes and Frog Legs are considered a food source, and all joking aside taste a bit like chicken. Frog Info and sources exist. Rats and Snails are also tasty. A dead Carcass may or may not be edible. A vegetable protein source without peer is the venerable Soybean, as the SoyFoods Org will attest, but the adaptable Amaranth plant seed and Buckwheat grain are high in protein too.