In the TV series Fossil is portrayed as incompetent and bizarrely unaware of common terms; for example he does not know how to dial with a phone and calls a portable tape recorder his "talk box". He is often very childlike and emotional. Though Fossil is chief zoo keeper, he knows nothing about animals, describing the elephant as "the grey leg-face man" and a bear as "the hairy Russian carpet guy". According to the radio series, Fossil also had a traumatic childhood. In the series, Fossil has his own theme song for the zoo: "Nicey nicey zoo zoo, for him and her and me and you!" In the radio series, Bob has a brother called Wilbur who reunites him and his mother, who had believed that Bob died in Vietnam.