Eliza is the main character, who (unknown to most) gained the ability to speak with animals after an encounter with an African shaman (as shown in the episode "Gift of Gab"). Eliza is portrayed as a geek by her extensive zoological knowledge and her glasses and braces. She has freckles and long red-orange hair that is usually worn in pigtails like Pippi Longstocking, and occasionally a ponytail. She also has a companion-monkey (chimpanzee) like Pippi Longstocking; but instead of superhuman strength, Eliza has the "super-power" of being able to talk to animals; meanwhile the name "Eliza" invariably derives from the name "Eliza Dolittle," from the film "My Fair Lady" and Doctor Dolittle, due her ability to talk to animals. She almost always wears a yellow dress, though later in the series she sports other clothes. Eliza suffered a serious attack of appendicitis while rock climbing in the Australian outback. Eliza is 12 in the series, being four years younger than Debbie as stated in "Gold Fever".
Debbie is a typical 16-year-old girl who is the most popular girl in the franchise and Eliza's older sister, interested in music and fashion, and who longs for the normal suburban life her parents' job deprives her of. Even though she ridicules Eliza, she truly does care for her. She commonly wears an orange camisole, a green flannel shirt, blue jeans (with holes deliberately torn in the knees as a 'grungy' fashion statement) and brown Birkenstock clogs. In The Wild Thornberrys Movie, she learns Eliza's secret after Eliza reveals it to the poachers that were threatening to hirt her if she didn't tell them how she knew about their plan to kill a herd of elephants. Debbie is amazed that Eliza gave up her gift to save her life and promises to keep her secret -- but only under the belief that if she doesn't, she'll be turned into a baboon. It is shown in the episode "Chew if by Sea" that Debbie suffers from chronic seasickness.
Nigel, the only child of Colonel Radcliffe Thornberry and Cordelia Thornberry, travels around the world with his family making wildlife documentaries for his own show. He resembles Steve Irwin and David Attenborough, and speaks with an English accent. He somewhat resembles Lt. Col. Algernon Hawthorne in It's a Mad, Mad, Mad, Mad World, played by Terry-Thomas. He is easily excited and is usually calm, even in the face of danger, and his catchphrase is "Smashing!", and offered a professorship at Oxford University. Much to his mother's disapproval, Nigel turned down the professorship. Although he is an expert at the natural world, Nigel is pretty slow when faced with other things; but he is always fascinated by nature, even in the face of his own demise as a result of it.
Marianne is Nigel's wife and operates the film camera in addition to driving the ComVee. Marianne is a strong woman, often the voice of reason, and sometimes loses patience with Nigel. She is usually the one to take on disciplinary duties, forcing Eliza to stay in the confines of the comvee, or forcing Debbie to complete her schoolwork. Marianne was revealed to be kicked off her High School's Field Hockey Team by a frustrated Debbie.
Darwin is a chimpanzee who travels with the family and is a loyal companion to Eliza. He usually wears a regular sleeveless shirt with blue stripes and blue shorts. He speaks with a distinct upper-class British accent. He tries to be the voice of reason to Eliza, however she rarely takes his advice, since he is almost always hesitant to follow her plans; in response, she accuses him of cowardice, once calling him a "crybaby in a tank-top" for his hesitancy. He was found by Eliza, and was the first animal she ever talked to. In 'The Gift of Gab' Darwin was seen in a flashback, stealing the sleeveless tank top that was once owned by Debbie,
Donnie is a feral boy who (as revealed in the 2001 4-part TV movie, "The Origin of Donnie") was raised by orangutans (similar to Tarzan) after his real parents, a pair of naturalists, were killed by poachers. The special also reveals that Nigel and Marianne knew his parents, prior to Donnie's birth. He commonly wears a pair of leopard-spotted shorts (presumed to not wear underwear underneath) and he loves to eat bees. He talks very wildly and unintelligibly in animal-sounds (but nothing Eliza can understand), but is able to adapt to most environments. Donnie is 4, but turns 5 in "The Origin of Donnie".
Tyler Tucker is a minor character of The Wild Thornberrys. He is a Marianne and Nigel's nephew through Marianne's sister Nancy Tucker, and the cousin of Eliza, Debbie and Donnie's cousin.
Sophie Hunter is a recurring character on The Wild Thornberrys. She is the mother of Marianne Thornberry, and the grandmother of Eliza, Debbie, and Donnie Thornberry.
Sophie Hunter is a recurring character on The Wild Thornberrys. She is the mother of Marianne Thornberry, and the grandmother of Eliza, Debbie, and Donnie Thornberry.
Cordelia Thornberry is a character in The Wild Thornberrys. She would love nothing more than for her son, Nigel, to settle down and become a tenured professor at Oxford. Unfortunately, that wish seems unlikely since the need for adventure is firmly implanted in her son's blood. Cordelia lives with her husband Radcliffe at Thornberry Hall in Scotland, a giant mansion filled with servants and luxurious rooms. Her wealthy upbringing makes it hard for her to accept her son's choice in the life he chooses to lead, as well as what he and Marianne subject their daughters to. Still, Cordelia is proud of her son in her own way, even if she has a hard time showing it. She was voiced by the late Lynn Redgrave.
Col. Radcliffe Thornberry, R.A.F., (Ret.) is the father of Nigel Thornberry. Listening to him, it is easy to hear where his son Nigel got his trademark voice, as well as his sense of adventure. Radcliffe lives along with his wife Cordelia at Thornberry Manor in Scotland. A former member of the Royal Air Force, he enjoys hang gliding, playing the bagpipes, and loves a good adventure.
