Mark has spent over 35 years caring for the animals at Lincoln Park Zoo in Chicago, IL. He counts elephants and lions among his close friends and has been involved in preserving the zoo's rich history. His zoo career began at the Children's Zoo and over the years he learned his profession as an animal keeper, zoologist, assistant curator and curator of mammals. He ended his long association with animals holding the endowed chair as the Abra Prentice Wilken Curator. Presently, Mark holds the title of Curator Emeritus. Mark has authored 2 children's books, and over 50 scientific and numerous popular articles. The University of Illinois Press has published his book on the history of the Lincoln Park Zoo entitled Ark In The Park. Over the years he has taught zoo management in the People's Republic of China, Guatemala, Japan and Mexico. His travels have taken him to Africa, leading tours to Uganda, Botswana, South Africa, Tanzania, Zimbabwe and Kenya. He has also escorted animals to and from Lincoln Park Zoo. Lions coming from the Kapama Game Reserve in South Africa, Spectacled bears going to a zoo in Venezuela or bringing a family of gorillas to Disney's Animal Kingdom were all part of the job. Mark traded in Lions and Tigers for dogs and cats when he worked as Director of Operations for the City of Chicago's Animal Care & Control. Presently he is working on a unique project with the Pittsburgh Zoo to record on video the animal stories of retired zoo and aquarium directors for future generations of historians and zoo professionals.