Animals slow down as they increase in size and speed up as they decrease in size. The animals with the slowest heart beats, metabolism, and breaths per minute are whales, elephants, hippos, etc (they also move slowly). The speedy mouse and hyper hummingbird are on the other end of the spectrum. There is also a correlation between size and life expectancy. Whales live longer than mice, which live longer than mosquitoes. However, the smallest stuff usually out lasts the big stuff in the long run. Mosquitoes (the species, not an individual mosquito) have been around way longer than elephants, and elephants will surely go extinct before mosquitoes.
Now let’s look at cities. Everything from crime to salaries to traffic increase with size, so unlike animals, size indicates speed. Here’s another difference: the larger a city is, the longer it will last—on average. Hiroshima and Nagasaki still exist after experiencing a nuclear explosion. Now go to Wikipedia and search ghost towns. Each share the same story: economic prosperity (golden rush, e.g.,) led to a small town (less than 100) until a flood, violence, or freak disaster killed the town forever. So in terms of longevity, big cities last longer than small ones, while big animals go extinct faster than small ones.
Also, fragility and size are correlated. Compare an elephant with a broken leg to a kitten or mouse with the same injury; the elephant is much worse off. Now compare a city that suffers an equivalent of a broken legal (e.g., natural or man-made disaster) to a small town that suffers something with similar destructive power; the small town is way worse off.
The one problem running throughout this is the false comparison between cities, species, and individual animals. Some more thought is required in this regard.