A new study led by postdoctoral researcher, Katrina Jones (S. Pierce Lab) and Stephanie Pierce suggests the makeup of a spine is one more characteristic that defines a mammal. The research, published in Science, shows mammal backbones are different than the vertebra of most four-legged animals in that it is made up of different sections - neck, thorax, and lower back - that take on different shapes and function separately. Jones and Pierce looked at the fossil record using museum collections from around the world. Along with their co-authors, the team examined dozens of fossil spines as well as over 1,000 vertebrae from living animals. Jones, Pierce and the team discovered that during mammal evolution, the spine gained regions, unlike the non-mammalian. Media: The Harvard Gazette, Science Magazine, Phsy.Org