Zug grew up as an only child in the semi-rural community of
Mount Holly Springs, where he began observing local flora and fauna at an early age. In the late 1950s, while studying at
Albright College in
Reading, Pennsylvania, he met zoologist
Albert Schwartz, who became his first major scientific mentor. Schwartz took him to
Cuba on research trips, where Zug was introduced to herpetological
fieldwork. He received his
Bachelor's degree in 1960 and his
M.Sc. in 1963 from the
University of Florida in
Gainesville, where he studied the
morphology of turtle penises. In 1968, he earned his
Ph.D. from the
University of Michigan with the dissertation
Buoyancy, locomotion, morphology of the pelvic girdle and hindlimb, and systematics of cryptodiran turtles. In 1975, he became curator of the herpetology department at the
National Museum of Natural History, a position he held until his retirement in 2007. Between 1971 and 1972, Zug spent six months with his family in
New Guinea. Supported by the
Smithsonian Institution, this long-term study focused on frogs, skinks, and geckos of the Australo-Papuan region. He later undertook additional research projects in the
South Pacific. In 1997, he traveled to
Myanmar at the invitation of Chris Wemmer for a training workshop with Burmese national park staff. He also participated in a herpetological survey program developed in collaboration with the
California Academy of Sciences and funded by the
National Science Foundation. Interns, research assistants, postdoctoral fellows, and other colleagues at the Smithsonian contributed to the project's results. Zug integrated slow-motion filming into his studies to document the locomotion of turtles and frogs. He applied the method of
skeletochronology to endangered
sea turtles, as it provided a reliable tool for determining their age and sexual maturity, which in turn informed conservation planning. He has published more than 100
peer-reviewed papers and over 160 additional scientific works, including four major studies on frog locomotion. In 2016, he received the
Fitch Award for excellence in herpetology. In 2024, Zug co-authored the book
Tortoises of the World with Devin A. Reese. == Eponyms ==