An annual convention of nature interpreters from all over the country has been going on this week in Iowa. Some 12-hundred nature interpreters have been attending a week of sessions on conservation, teaching, history and ecological issues in Des Moines. The nationwide conference brought hundreds of trail guides, teachers and museum curators to Iowa. In addition to workshops, tours and an awards banquet, there’s an exhibit hall with vendors selling teaching tools, musical instruments, and…bones.About 25-thousand a year, from hunters, trappers, road-kill, wherever the supply is legal and ethical. Jay Villamarette of Oklahoma says his company, “Skulls International Unlimited,” uses domesticated beetles to clean the bones, and will only sell plastic replicas of endangered-animal bones. Most sales are to schools, museums, teachers and interpreters using them in interpretive programs. But there’s nothing to prevent a private collector from buying an animal skull or a complete skeleton, which could cost anywhere from five dollars to several hundred. The vendor, who says all are collected in places and ways that are in accordance local laws, also calls them “osteological specimens.” For more, see www.skullsunlimited-dot-com.ss