After a large nuclear war, most of the survivors get the hell out of dodge, and leave the large cities to build communities in places with nearby water sources, land for farming, and etc. But, the cities they left behind are still there, so my question is, which animals would be able to survive in those abandoned cities?
closed as too broad by kingledion, sphennings, elemtilas, rek, StephenG Feb 22 '18 at 4:19
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Cities will be reclaimed by the surrounding biomes.
The species that are native (or comfortable) in city's climate will dominate there after people have left. Native species will get competition from people's pets, mostly dogs and cats, but dogs and cats are not likely to dominate in the long run. Birds of all kinds will find abandoned cities very comfortable because they should be able to find plenty of refuge on the roofs and upper stories. Good rock climbers, like goats and large felines may also like it there.
City's underbelly, its tunnels and basements are not going to be much occupied, unlikely to what most post-apocalyptic lore would claim. There will be no food there, and those areas would be like natural caves, mostly empty of any inhabitants.
Of course, you can get creative and populate your cities with all kinds of mutant animals, even sapient ones.
While the other answers have focused on mammals and avians, I'd like to draw attention to several other types of animals that will do well after an apocalypse:
Yup, these creatures will definitely survive and breed. Flies, cockroaches, ants, and beetles are commonplace and will have access to sufficient food. Bees and wasps also have potential, while mosquitoes are only likely to do well where warm-blooded creatures with thin skin exist.
I can easily envisage giant, mutated versions of these insects terrorising city wildlife.
Yup, spiders. There are large numbers in cities currently, and they'll survive and breed since their usual prey, insects, will be plentiful. Large-scale variants are also possible, though not to the extent of insects.
Especially in tropical, semi-tropical, and arid regions, reptilian animals such as lizards and snakes will abound. Lizards will feed on insects, snakes will feed on small mammals.
There will be lots of animals reclaiming the cities, many of them dependant on the native biome and the nature of the apocalypse.
Rats will probably bloom soon after the apocalypse, but without humans to keep supplying them with food they will soon start dying out, this can be really troublesome to any nearby comunity as those rats can start invading nearby settlements.
Dogs will probably be left behind by the thousands and it will take no time for them to go feral and start roaming the streets looking for food. Once again, they can endanger nearby settlements as food on the cities dwindle.
Finally you will have cats, they will be less of a problem, but your survivors will probably be eating cat meat very soon.