Przewalski's Horse

The final confirmed wild sighting was in the Gobi in 1969. Everything alive today descends from a captive stock traceable to roughly a dozen effective founders, which makes the genetics of the recovery as demanding as the logistics — every pairing across the studbook is managed to slow the loss of what variation remains. Reintroduction began in the 1990s at Hustai and Takhin Tal, and the animals now breed on the steppe unaided.

It is not the ancestor of the domestic horse, as long assumed; genomic work places it as a separate lineage, and the domestic horse descends from a different population entirely. Przewalski's horse also carries sixty-six chromosomes against the domestic horse's sixty-four, yet the two produce fertile hybrids — which is itself a persistent problem for keeping the reintroduced herds distinct.