He was a high school science teacher before becoming a college professor. He published numerous books and articles, including "Ulendo: Travels of a Naturalist in and out of Africa", "High Jungles and Low", "So Excellent a Fishe" (about his green turtles), "The Windward Road" and several Time-Life books such as "The Everglades" and "The Reptiles". He also authored the "Handbook of Turtles", and with , "Guide to the Reptiles, Amphibians and Freshwater Fishes of Florida". While a serious scientific and nature writer, he also published a parody of scientific taxonomic keys - his "A Subjective Key to the Fishes of Alachua County, Florida", affectionately known as the "Carr Key".