Got this from the guys over at Die Squirrels Die, good info to help you better prepare for war, or if you preferr young squirrels to older squirrels when cooking.
Cooks and hunters use these guidelines:
"Assuming your squirrel is not collected on the subway and has no cards in its possession, here are the standard tests for age. None of them are foolproof, so do them all and get a general impression.
1. Ear pliability. A younger animal will have soft, pliable ears even after rigor mortis sets in. An older animal will have dry, stiff ears.
2. Fur condition and tightness to skin. An older animal will have drier fur with more hollowness to the individual hair shafts, and the pelt will be tighter to the muscle. The skin may also be thicker, and show less of a fatty deposit on the underside.
3. Teeth size, coloration and wear. Older animals have worn, smoother and yellower teeth. Whiter, smaller, sharper teeth are the sign of a younger animal.
4. General muscle tone, flexibility, tenderness. A younger animal will retain more pliability even when dead, and a finger poked deeply into a haunch will cause the meat to dent in and then rebound more quickly.
5. Ossification, thickening or fusing in the bone joints, thick, toughened pads on the bottoms of the paws and the leg joints or a protuberant spine and shoulders can signify an older animal in poorer condition."