The number of tigers in the wild has risen from an estimated 3,200 in 2010 to about 3,890 in 2016 — a gain of more than 20 percent after a century of decline, according to the World Wildlife Fund. The group says the tiger populations have grown in at least four countries: India, Russia, Nepal and Bhutan.

Early in the 20th century, the world had more than 100,000 tigers in it, as the author Caroline Fraser wrote in a report for Yale University back in 2010.

The population increase "is a pivotal step in the recovery of one of the world's most endangered and iconic species," said Ginette Hemley, senior vice president of wildlife conservation at WWF.

The findings are being praised as a key step toward a lofty goal that was set in 2010: to double the number of wild tiger populations worldwide by 2022. The survey gives a progress report at that initiative's halfway mark.

The WWF cites factors such as better survey processes and enhanced protections in explaining the gains. But it adds that the world's tigers remain threatened by shrinking habitats in Asia and that they are also a prime target for poachers.

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