Yeah 40lbs is a big cat. I shot one this year with my bow, shot him a little further back then I would have liked but he rolled, growled and went about five yards and dug in. 15 minutes later he was dead but like someone said before it was tough seeing him in the daylight so you might have walked right by him. My cat came in at 22.5lbs and was a lot bigger than the female I shot. From what I've heard the average is between 18-30 but I don't hunt em so not really sure. Good luck finding him I'm sure he's right there get a dog!