Sure they can , most housecat wont . Rats can be very aggressive and are not an easy prey for cat . Seasoned outdoor cat , no problem . Some cats are more hunter than other . I guess that in the old times cats were not as well nourished and probably manage rats . I ' ve read that the black plague was in part because cat were perceived at the time as evil , specially dark one and killed massively in urban area . Edit source maybe not the best andtheBlackPlague <| sep |> In that case , the user probably changed it to this icon , which would mean that it means nothing in particular . <| sep |> I really wanted to like Neuromancer , but it just seemed so confusing and all over the place . There were times when I had no clue what was going on .