There's a pretty interesting study on overpopulation that took place in the 60's and 70's I think you guys might find interesting. Rats were put into a small area and observed as they reproduced. Well before the population even came close to the capacity of the enclosure things began to fall apart in a way you might find eerily familiar. As the population grew the most attractive and powerful males asserted themselves and all of the female mice migrated towards them. As this happened the rest of the male mice became dissatisfied with things and stopped mating altogether and created their own community on opposite sides of the enclosure. During this phase the female rats that mated with the alpha male rats became neglectful towards their children often leaving them to die as they left to mate with the other males. As this progressed more and more rats began to see the futility in mating until by the 600th day the colony moved towards extinction, as few new rats born and those that were did not survive long.

Edit: it was mice not rats, same idea though.

Edit 2: u/ludakrit provided a link to the wiki https://en.wikipedia.org/wiki/John_B._Calhoun#Mouse_experiments