CENTRE COUNTY, PENNSYLVANIA—According to a statement released by Penn State University, a study of 18,000-year-old eggshells recovered from archaeological sites in New Guinea suggests that people collected cassowary eggs shortly before they were due to hatch thousands of years before the domestication of the chicken. The inside of an eggshell changes as the chick draws calcium from it, allowing the researchers to estimate how old the developing chick was when the egg was harvested. Team member Kristina Douglass said that most of the shells in the study reached late stages of development, indicating that the chicks may have been collected as food. Few of the late-stage eggshells show signs of cooking, however, Douglass explained. Cassowary chicks, the researchers noted, imprint readily to humans and are easy to raise to an adult weight of more than 40 pounds, although few cassowary bones have been found at archaeological sites. The eggs may have been collected just before they hatched in order to raise the chicks, which are still traded in New Guinea today, they added. Read the original scholarly article about this research in Proceedings of the National Academy of Sciences of the United States of America. To read about decorated stone statues found on New Guinea that may be more than 3,000 years old, go to "Honoring the Ancestors."