It is a well-known novelty dish in parts of the American West and Western Canada where cattleranching is prevalent and castration of young animals is common ("prairie oysters" is the preferred name in Canada, where they may be served in a demi-glace, not deep-fried). In Oklahoma and North Texas, they are sometimes called calf fries but only if taken from very young animals. In Spain, Argentina and many parts of Mexico they are referred to as "criadillas," and they are colloquially referred to as huevos de toro (literally, "bull’s eggs"; huevos is a Spanish slang term for testicles) in Central and South America. Rocky Mountain oysters are sometimes confused with lamb fries or animelles (lamb testicles), which are served in a manner similar to Rocky Mountain oysters. A few other deceptive terms, such as "cowboy caviar", "Montana tendergroins", "dusted nuts", "bull fries" or "swinging beef" may be used.
The dish, purportedly cowboy fare, is most commonly found served at festivals, such as the ones in Virginia City, Nevada; Montana; and Phoenix, Arizona, amongst ranching families, or at certain specialty eating establishments and bars. They are, however, also readily available at some well-known public venues (e.g., at Coors Field during Colorado Rockies baseball games). Eagle, Idaho, claims to have the "World's Largest Rocky Mountain Oyster Feed" during its Eagle Fun Days (now held the 2nd weekend in July).
The primary goal of testicle removal is not culinary. Castration in veterinary practice and animal husbandry is common and serves a variety of purposes, including the control of breeding, the growth of skeletal muscle suitable for beef, and temperament alteration.