Do All Vehicles Need A License Plate In Michigan?

I was driving back to work from lunch and I noticed that the vehicle in front of me didn't have a license plate. 

It was a dump truck and the person driving is probably just a hard working man or woman earning their pay just like every other hard working American. I just couldn't help but notice that it didn't have a license plate.

That or it was so dirty you couldn't see if it had one even close up.

Now maybe because it is a dump truck it is allowed to have it some place other than the back because it is constantly dumping out the back. I'm not sure.

I am not trying to call anyone out or anything like that, I am just curious if all vehicles need them?........ Anyone know?