Four of the five Mexican gray wolves released last October to re-establish the endangered species' numbers have died, The Associated Press
reports. The wolves, which were reintroduced to a mountain range just south of the U.S. border, were poisoned, U.S. and Mexican wildlife officials have concluded.
The effort to help animals
and repopulate the wolf in its natural range - Mexico and the American Southwest - has been 20 years in the making, the news outlet reports. The three females and two males that were released were fitted with GPS collars for easy tracking. As of now, officials are unsure whether the poison - which is commonly used to kill rats and other pests - was set out intentionally for the wolves.
Still, the Mexican wolf, an endangered species, is on the rise, according to The Arizona Republic
. Total numbers have increased by eight, bringing the total number of these canines to 58. Even better is that more than 90 percent of the wolves on the ground today were born in the wild, giving hope that the population is self-sustaining.