I knew Commander would come through! More importantly, why does the schlub janitor at work continue to smell unwashed. He doesn't even need to hunt deer or live in a cave.

1. Team effort: one or more members of the tribe approaches the deer, which, if they approach on three sides, drives it into the club of the man on that side.
2. As you suggested, being upwind of the deer, then "he uses The Club."
3. Drive/stampede deer off cliff.
4. Attack from above, i.e. in a tree.
5. They discovered this, so stripped naked, bathed in a stream/creek, then hunted.
6. Invented the slingshot, or learned to put a rock in a sling for throwing.
7. Got tired of subsistence level survival as hunter-gatherer, turned to agriculture.

Odor might not be that significant, as there are a lot of smells in a forest.

Based on the personal body odor of the janitor at work, I find it very difficult to believe that an unwashed caveman could sneak up on a prehistoric deer. I can smell the guy from ten feet away. Imagine an unwashed Neolithic hunter smelling of body odor and wood-smoke trying to stalk anything with a nose. I suppose being upwind would help as well as multiple hunters, but still...

THE
OOKA-GAKKA!
AARDVARK