Cities are making mammals bigger. While climate change is causing some animals to shrink, a new study shows urbanization is causing many mammal species to grow both bigger and longer, possibly because of readily available food in places packed with people. Source 3p.
I could see our plentiful trash and, due to pest control for many other forms of animals, the lack of competition from many other predators/species making it so that urban areas are havens for some mammal species. Rats and major cities would most likely be the most readily available example. Compare NYC rats to some regular average field rats. The NYC rats are MONSTERS comparatively.