RENO, Nev. (AP) — Despite overall numbers in the tens of thousands, mustang advocates say the wild horse is on the verge of going extinct in North America for the second time in 13,000 years and deserves protection under the Endangered Species Act alongside grizzly bears, the desert tortoise and humpback whales.

Efforts to halt mustang roundups in Congress and the courts have been unsuccessful over the past decade, but two groups in a petition to the U.S. Fish and Wildlife service are focusing on genetics and research they say prove the horses are a native species. They say growing threats from development, livestock grazing and government gathers are jeopardizing the genetic viability of individual herds in 10 states from California to Montana.