How Smart are You?

I've never had a good mind for riddles. They've always make me feel so confused that I feel like I want to run screaming away in frustration. So when I picked up this book at the library on riddles, I thought it might be a good way to challenge myself without feeling put on the spot. It did not help. I am just as confused as ever. I wondered how many people could figure out a riddle I'd heard in the past. Here it is:

A dead man lays in a field, alone. There's nothing in the field for miles but more meadow. He has a backpack on his back. No one knows he is there, dead. He was not murdered. He did not walk/run or arrive by an automobile. He did not die of starvation, dehydration, heat or cold. How did he die, and what's in the backpack?

You figure this out; I send you $5.

p.s. this is obviously easier than I thought since someone two people answered me within like 30 seconds. so if you don't want to know the answer, and ponder it for a minute, don't look at the comments. :) i knew money get me some responses! if all else fails - pay 'em!