According to the new study published in the journal Science, only 1,280 individuals were left after the extinction-level event.
It’s thought a group of 100,000 of this unknown human relative existed before the mysterious and deadly event.
The researchers note that there are now around eight billion human beings and we’re driving other species to extinction.
They wrote: “Had a researcher looked at the world sometime between 800,000 and 900,000 years ago, however, the picture would have been quite different.
“Hu et al. used a newly developed coalescent model to predict past human population sizes from more than 3000 present-day human genomes.”
They noticed a reduction in population size from around 100,000 to about 1000 individuals.
This smaller group was said to persist for another 100,000 years before the number started to rise again.
The researchers explain: “Results showed that human ancestors went through a severe population bottleneck with about 1280 breeding individuals between around 930,000 and 813,000 years ago.
“The bottleneck lasted for about 117,000 years and brought human ancestors close to extinction.”
Experts say this change happened during a period of significant change in the climate.
It also coincides with significant speciation events, which refer to a time when a new plant or animal is created.
Although we don’t know the species of human relative that faced these issues, the researchers suspect it was an ancestor of Homo heidelbergensis.
It’s thought some of the Homo heidelbergensis evolved into Neanderthals.
The results of the study also coincide with a gap in the fossil record around this time period.