To survive in MGS3, you'll need to eat. Pretty much any wildlife is edible, but their effects (and taste) vary.
Siberian Inkcap
Tastes awful and recovers very little stamina.
Russian Glowcap
Recharges your batteries when you eat it. You can also throw it to use as a light source in dark areas, or throw it at Volgin to absorb his lightning attacks.
Calorie Mate
You can find these in enemy supply rooms. They taste great, never spoil, and recover two whole bars of stamina.
Instant Noodles
You can find these in supply rooms. EVA will give you a few as well at the top of the mountain overlooking Groznyj Grad. They taste just as good as Calorie Mates, and recover about the same amount of stamina. (Strangely, they're obviously of Japanese origin, but how they got into Russia is completely unknown, considering that Japan and the Soviet Union were never allied.)
