Many of them travel and hunt at night.
Phototaxis refers to a movement reaction to a light source. For them, it's called negative phototaxis.
Rejection of lighted areas: road lighting reduces their nocturnal living area (roe deer, foxes, badgers).
Mammals are adapted to moving around and hunting at the beginning and end of the night. Their eyes are large enough to catch the maximum amount of light. They have difficulty adapting to variations in light intensity: this explains road collisions.
Development of a cautious attitude (towards lighted areas): inattention to other signs of a predator in the shadows, who can clearly see its prey. The same phenomenon occurs as with insects: overpredation leading to accelerated species decline.
Lighting can also lead to hormonal imbalance, with the following possible consequences:
We're seeing a fragmentation of dark areas, and therefore of their natural habitat. Species living in Paris a century ago are now found 70 km from the city.
For more information on metabolic and hormonal problems, see the page on other mammals: humans.
