Wildlife -- and your car

I hit a very large wolf in Idaho in July 2010 on Interstate 90 at a speed of 75 miles per hour coming back from Spokane. The impact ripped the front left portion of my bumper. Thankfully the air bag did not deploy. Just curious though… why didn’t the air bag go off with that hard of a hit?

PS… I have a duct tape bumper… or is it duck tape bumper?