I know its too late now but when you have a massive event like mass death. Dotn close the game. Look at the log file right away. Each time you start the game it catches up everything to current time and its all in the log file. So if everyone aged and died it would show it or basically what happened to cause the death. Its a very useful tool but you are correct 1 male can make many babies so you got lucky there. On my game that is completed i usually try to take the youngest male and check him as a breeder and i never run low on people then he just keeps going and going and going like the energizer bunny.
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Village Monk
"There's no place like 127.0.0.1"