Raised by her grandparents as heir to the Rafter S Ranch, Mary grew up shunning socials and other affairs for ranch work. The hard work and values she learned on the ranch made her into one of the most influential women in Texas. In addition, she was the first female president of the San Antonio Livestock Exposition, the first woman to serve on the Texas Animal Health Commission and the first woman chairman of the Texas A&M Board of Regents.