I've been hunting, fishing, and camping all over Colorado for over 50 years. Also spent years as a criminal investigator for a state agency covering most of Colorado. After retirement I was a consultant and investigator for insurance claims departments, working cases all over Colorado (and adjoining states). The short version is that I have spent over a half-century traveling around Colorado.

I have seen lions at least 20 times over the years. Of those only 3 or 4 occurred prior to about 1995, and the rest since then. I actually see a lion about once each year now, and sometimes more frequently depending on my activities.

Mountain lions were considered scarce and sightings were rare until about 20 years ago. Even a fleeting glimpse of a lion seemed to be a once-in-a-lifetime moment. Now they are becoming almost common, and confrontations between lions and humans (as well as pets and livestock) are very real problems in many areas. The big cats are living and hunting in close proximity to human developments and demonstrating much less caution about contact with humans, dogs, vehicle traffic, etc.

Lions are magnificent creatures. I am actually pleased to see the Colorado population doing well. At the same time I can't help having some concern over the frequency of dangerous encounters. Livestock, pets, children, even joggers have been attacked by lions in recent years, frequently near major cities (sometimes inside the city limits). I suspect that competition for territories, combined with increasing lion numbers, has resulted in their movement into the less remote and wild areas and into closer proximity to humans. While in their prime lions will exist almost exclusively on deer, elk, and other game animals. Older animals, and those that have sustained some injury limiting their abilities to hunt effectively, will do what they have to do in order to survive. Sheep, cattle, or horses in fenced enclosures, dogs and cats roaming around, children playing, joggers on trails, all of these might be interesting possibilities for a hungry predator.