Imo, the jump in intelligence, wood savvy, or whatever you choose to call it is exponential. I don't consider a 3.5 a mature deer.

This is just one of many anectdotal observations I have witnessed over the years that has caused me to form this opinion.

A few years ago, I targeted a 4.5 to fill my buck tag with. I came close on two occassions, but never could get the guy out of the brush. He always sensed something wasn't right and never presented a shot.

On the last day of the season, I am set up in funnel between a bedding area and wheat field and with about 15 minutes of season left, here he comes but following a 3.5 yo buck. It was very still and quiet.

As they approach my 30 yard window and I start to draw back, the old deer "senses" or hears the drawing of the bow and jumps through his skin and in the blink of an eye he is gone. The younger deer just stands there giving me the perfect broadside shot not even aware of what is going on.