See the chart for the time of day when the sun sets. When hiking be careful not to dislodge a rock sending it tumbling down on hikers below. We are lucky here in southern Nevada, there are no bears, but we have five poisonous rattlesnakes. Keep a sharp eye where you place your hands and feet. The worst times for snakes are October and April.
Snakes are rare in Mt. Charleston due to the elevation.
If bitten, get to a hospital. Mountain Lions are said to roam in Red Rock and Mt. Charleston, but I've never seen one. And I've never heard of anyone being attacked. If you do see a mountain lion, don't run. That's it for dangerous animals and reptiles.