At the Field Museum, Donnelly’s clients are almost exclusively scientists. With input from them, she interprets, emphasizes, and edits until the drawing tells a story of its own. She has a sense of awe and respect for her subjects, many of them fossils over 200 million years old. This is not the dull job of replication best left to the camera. Donnelly describes feeling a great sense of mystery and discovery in reconstructing prehistoric animals, “Slowly, a jumble of broken fossils reassembles into a real creature never before seen by human eyes. A wire skeleton painstakingly fleshed out with clay muscles takes on form and, in my mind, life—I can see my Placodont forging through ancient seas with powerful thrusts of its tail, crushing mollusks with enormous round teeth, utterly unconcerned with the peculiar bipedal beings that will inhabit the earth in eons to come.”

Whenever possible, Donnelly works from specimens. In pursuit of authenticity, she has traveled to Africa, Australia, the Galapagos, and the South Pacific to work on location. Because color disappears underwater according to wavelength and she wants to avoid the “false” color of flash photography, Donnelly will sometimes sketch underwater on drafting film, diving with either graphite or colored pencils and a laminated paint color chart to assure the accuracy of color at different depths.