Ilikemuppets said:
I always though Prairie Dawn was six. Grover is too worldly to be a child. Cookie's vocabulary is far beyond that of a child. Telly and Baby Bear are somewhere between the ages of 4 and 6. I would say 5. They may have given Telly an age after a while. And they made Frazzle and Herry like kids after a while.
I'd say that Cookie's hard to place in terms of age: he's got an adult's vocabulary and above-average problem-solving skills, but a child's emotional life and obsession with cookies. (The weird grammar--his use of "incorrect" pronouns and verbs--I'd blame on his species instead of his age. Alien creatures do tend to speak strangely, and he
was originally conceived as the scary, eats-anything monster that young children might imagine.)
Grover, I'd call a young adult (even if he lives with his mother and calls her "Mommy"): he's worked several adult jobs, speaks very proper English compared to the childlike characters, but still tends to get over-excited and insist on doing things his way.