B.C.
The titular character of the "B.C." comic strip is B.C., a caveman with reddish-brownish hair. Hart claimed that B.C. is the "straight man" of the cast of characters and that there's a little bit of himself in B.C. As the straight man, B.C. often acts as the fall guy for other characters' jokes. Naive and a little messy, B.C. is also considerate of others. He sometimes appears as "The Midnight Skulker," a superhero who responds to a beacon of light.
Grog
Even among cavemen, hairy Grog appears utterly simplistic. Called the "caveman's caveman" at the Johnny Hart Studios site, Grog rarely speaks. Instead, he grunts and says simple words like "poop" out of context. Wild and mischievous, Grog is strong enough to put a javelin in his mouth and spit it to the moon.
Peter
The blond caveman in "B.C." is Peter, whom Hart modeled after one of his former coworkers. Peter is intelligent and invents items that are thousands of years ahead of his time. He's also discovered oil. As president of the "Prehistoric Pessimists Society" and the inventor of the "Truth Pedestal," Peter is the most pensive of the "B.C." characters.
Fat Broad
A short-haired woman with no name -- only the title "Fat Broad" -- appears in the comic strip in a purple dress. She's another "straight man" (or "straight person") in the strip, although she cracks a few jokes wryly. Many of her jokes center on subjugating men and dieting.
The Anteater
"B.C." features a number of animal characters as well. The Anteater -- who inspired the University of California, Irvine sports team mascot in 1965 -- speaks to other creatures, in particular the ants. He makes the sound "zot" when eating ants.
Queen Ida
Queen Ida is the haughty and demanding ruler of the ants in the strip. The real given name of Hart's wife, Bobby Hart, is Ida. Queen Ida appears yearly in the strip on December 3, which is Bobby Hart's birthday. The ants in the strip try unsuccessfully to placate their ruler.