From the text:
Synanthropes Lite: a game of applied anthropology for 3-5 players.
When Humanity disappeared, vermin inherited the Earth. They took over the cities. Adapted the technology. Evolved. Grew intelligent. Developed their own societies. Synanthropes were once the animals that lived in niches that Humans created.
They became civilizations which were almost Human: resourceful, greedy, clever, ambitious, dangerous, and always curious.
You play members of different species, sent to a neutral site—an old Human barn—to discuss a border dispute.