The group believes the bill could wipe out America's wild horses and burros in Nevada, where most of them currently live.
"We are concerned native wild horses would be wiped out if AB 329 is passed," explains Kerry Becklund, director of outreach for Protect Mustangs.
"Indigenous wild horses belong to all of America and must not be removed or killed because special interest groups lobby to prevent them from drinking water in Nevada."
AB 329 reads: "Section 1. Chapter 532 of NRS is hereby amended by adding thereto a new section to read as follows: As used in this title, unless the context otherwise requires, 'wildlife' means any wild mammal, wild bird, fish, reptile, amphibian, mollusk or crustacean found naturally in a wild state, whether indigenous to Nevada or not and whether raised in captivity or not. The term does not include any wild horse or burro.'
The executive director of Protect Mustangs, Anne Novak, says: "Attacking wild horses and burros in 'water wars' goes against the American public's wishes.
"Besides healing the land, they are living symbols of American freedom who must be protected and preserved."