No wild animal is dumb and most are to a degree difficult to kill. However the older the deer and the more hunting seasons it has lived throughthe wiser and harder to kill it becomes. Thinking a year and a half old deer is as smart or wise as a 3 or 4 year old deer would be the same as saying you are no smarter or wiser now at your age than the average 15 year old is today. Just common sense.