"Survival of the fittest" can be translated to Latin as "salvos aptissimum".
Other sources suggest that it could also be translated to "non nisi aptissimi supervivunt" (only the fittest survive) or "aptissimi soli supervivunt".
A bit of a trivia, Latin was just one of many Italic languages spoken in central Italy. It was the language of the area known as Latium (modern Lazio), and Rome was one of the towns of Latium.
Modern Latin was used by the Roman Catholic Church until the mid 20th century and is still used to some extent, particularly in the Vatican City, where it is one of the official languages. Latin terminology is used extensively by biologists, palaeontologists and other scientists to name species and specimens, and also by doctors and lawyers.
To learn more interesting facts about the Latin language, visit Omniglot.
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