https://phys.org/news/2018-11-red-dead-redemption-virtual-ecology.html

Red Dead Redemption 2 features more than 200 species of animal in a variety of habitats, and its record breaking success suggests that authentic natural environments which mimic the ecology of the real world will become a mainstay of future titles.

Video games have grown in scale and complexity to the point where intricate virtual ecosystems of this kind are now possible, with flora and fauna living and behaving in these virtual worlds as they do in ours.