Doctor Dolittle's Post Office by Hugh Lofting

The next thing I must tell you about is the Prize Story Competition: The fame of the Puddleby fireside-circle, where the Doctor had amused his pets with so many interesting tales, had become quite a famous institution. Too-Too had gossiped about it; Gub-Gub, Jip and the white mouse had boasted of it. (You see, they were always proud that they could say they were part of the great man's regular household.) And before long, through this new post office of their own, creatures all over the world were speaking of it and discussing it by letter. Next thing, the Doctor began to receive requests for stories by mail. He had become equally famous as an animal doctor, an animal educator and an animal author.

From the Far North letters came in by the dozen from polar bears and walruses and foxes asking that he send them some light entertaining reading as well as his medical pamphlets and books of etiquette. The winter nights (weeks and weeks long up there) grew frightfully monotonous, they said, after their own supply of stories had run out -- because you couldn't possibly sleep all the time and something had to be done for amusement on the lonely ice-floes and in the dens and lairs beneath the blizzard-swept snow. For some time the Doctor was kept so busy with more serious things that he was unable to attend to it. But he kept it in mind until he should be able to think out the best way of dealing with the problem.