Can I take the horns from a dead animal that I found?

Answer:

Possession and Sale of Wildlife Found Dead:

Protected species of wildlife that have died of natural causes are generally considered property of the state and may not be possessed.

But parts of big game species – hides, horns, bones, antlers, elk teeth, bear, lion and wolf parts – may be recovered and possessed for personal use if the animal died of natural causes. Lawfully recovered and possessed parts – except horns from bighorn sheep – may be sold, transferred, purchased or bartered, when accompanied by a statement on how it was obtained.

Edible meat from game animals taken from the wild may not be purchased, bartered or sold.

Recovery, Possession and Sale of Bighorn Sheep Horns:

Horns from bighorn sheep that have died of natural causes may be recovered and possessed. All bighorn sheep horns must be presented to Fish and Game for marking with a permanent pin within 30 days of recovery. It is unlawful to sell, barter or purchase bighorn sheep horns obtained under these circumstances, or to transfer ownership of recovered bighorn sheep horns without a permit from Idaho Fish and Game.