When Clint Walker Turned Down The Role...

When Clint Walker turned down the role of Michael Kelly, later played by Christopher George, the makers of this film should have bothered to find out why. If they did find out they should have taken any advice he had. Clint was famous for being in 1966's Night of the Grizzly. I would think he would have had good knowledge of how to portray a role in another bear movie.
I'd be very interested in learning why he turned down the role. Was it because of how Michael Kelly was written? Or did it have something to do with the bears portrayal? After all, it is well known that bears do not kill by squeezing(Don Strober's death). They kill with their teeth and claws as was correctly portrayed in The Night of the Grizzly(Sam Potts death).