ANN ARBOR, MICHIGAN—CNN reports that a team of scientists led by Brian Stewart of the University of Michigan analyzed levels of strontium isotopes in 30,000-year-old ostrich eggshell beads recovered from southern Africa’s Lesotho highlands, and compared the data with how much strontium is found in soil and vegetation samples in different regions. The researchers determined that about 80 percent of the beads in the study had been made from shells that did not originate in the Lesotho highlands. Stewart said the ornaments had come from at least 200 miles away, and may have been crafted by hunter-gatherers living some 620 miles away. Modern hunter-gatherers, he added, use such beads to begin and maintain relationships with other groups. Ancient beads may have served a similar purpose, he explained. The beads may have been exchanged along with information about resources, the condition of the landscape, other groups of people or potential marriage partners, animals, and plants. To read about a 24,000-year-old poison-tipped stick and other artifacts—including ostrich eggshell beads—recovered from a South African cave, go to "First Use of Poison," one of ARCHAEOLOGY's Top 10 Discoveries of 2012.