A retired executive who I worked with for 6 years grew up in Idaho where they had cougars and still do to this day. He was ahunter and said you could go a life time living out there, be looking for them, and still not be able to sight one, unless you were hunting them with trained dogs.
They are nocturnal, roam over a large range, and great sense of hearing and sight.
Here is a good link describing them, interesting, doubt if we will ever see one on our fishing trips to gods country.
Since white tails are one of their prime preys I can see why they can survive in Michigan.