This 18-cent Bighorn Sheep stamp was part of the "American Wildlife" booklet pane, the first U.S. booklet to feature ten different stamp designs. The photographs for the series were taken by National Geographic photographer Jim Brandenburg, marking a shift towards photorealistic depictions of wildlife on stamps. The Bighorn Sheep, with its majestic curled horns, is a quintessential symbol of the American West. Historically, their populations were decimated by disease transmitted from domestic sheep and by unregulated hunting. By the early 20th century, their numbers had fallen dramatically. The issuance of this stamp from Boise, Idaho, was particularly fitting. Idaho is home to significant populations of Bighorn Sheep, including the largest single population of Rocky Mountain bighorns in the Hells Canyon area. The state has been a leader in conservation efforts, including translocation programs to re-establish herds in their historic ranges. This stamp, therefore, not only celebrated the animal itself but also the dedicated work of conservationists in states like Idaho to ensure its survival.