"Why Dinosaurs became extinct"

I am doing a "funny", I ran across the web surfing around, saw my favorite "Far Side" cartoon.  The last time I saw this cartoon, was at a Spencers novelty store at Southlake mall in the early 80's.  I remembered that it was a poster and I wish I had purchased it back then but I was heading to the video arcade to play Battlezone and Zaxxon.  I kinda wish I had bought the poster.  I probably would still have the poster.  I have a "Wile E Coyote and the Roadrunner" poster amongst all of my various souvenirs from my military travels and swag gotten from Ford Motor company and my present employer.  That is where I keep all of my many history books,my relic computer with the faithful Windows XP, my comic books from Fox Trot, Bloom County and All of my Far Side Cartoons. among many other things.  It is my mancave, \This place has camo netting on the windows,  and other things that would offend my wife if it was any other place in the house.  Her decorating taste stop at the door.  I have a sign that my wife got for me a couple of years ago:

All of my "Far Side" books, none had this cartoon.  I just happened to run across it I think doing a google search for something else and I was very surprised since I haven't seen this cartoon in decades.
     I have looked for this cartoon for many years and ran across it purely by accident.  I wish I could find it in poster from but will have to settle for the digital image.

I remembered laughing my a$$ off when I saw it.  I kept thinking about the kids sneaking around the corner at school trying to catch a smoke before they got caught by the principal or a teacher.  Remember this was the early 80's and the kids still had fear of authority figures...Unlike now.