In 2009, with populations down at least 80 percent and a new dam on the Aras River threatening to destroy a large portion of the snake’s habitat, the International Union for Conservation of Nature listed the ocellate mountain viper as “critically endangered.”

[...] The Saint Louis Zoo coordinates a Species Survival Plan (based on the programs created by the American Association of Zoos and Aquariums) for the ocellate mountain viper, which includes a cooperative breeding program among several zoos. There aren’t many zoos that hold these snakes, though. Saint Louis is one of only three in the U.S. with the species in their collections, and they have the majority: Including the nine snakes born on August 16, Saint Louis Zoo has 23 of the 28 ocellate mountain vipers in the U.S.