A buddy of mine and I won the science fair at my school and went on to the Maryland State Science Fair in 1971/1972 with a project where we launched guppies and small white mice in some model rockets. The very first mouse shot we miscalculated the engine required. We boosted the panicky little guy with a D engine with too short a delay charge. It was still going up like a bat out of hell when the chute came out. It ripped clean off and the !QUOT!payload!QUOT! container fell earthward. In the HUGE 40 acre or so field we were launching from, there was but a single two lane road. Murphy's law was in effect and the damn thing landed smack dab in the middle of one lane of traffic, on the hard concrete. We ran up expecting a smear of blood to be that that was left of our brave Mousonaut. All of the cars were going around him and he was fine, wiggling around, happy as can be. Ahh the bliss of ignorance. We proceeded to boost him towards the heavens many times more. Based on that, I'd say the average white mouse can take 400 or so Gs without a G-suit.