The Thing in the Attic - James B. Blish

Honath the Pursemaker is a heretic. He doesn’t believe the stories in the Book of Laws which claims giants created his tree-dwelling race. He makes his opinion known and is banished with his infidel friends to the floor of the jungle where dangers abound. Perhaps he’ll find some truth down there. – The Thing in the Attic is one of Blish’s Pantropy tales and was first published in the July, 1954 edition of If, Worlds of Science Fiction magazine. (Summary by Gregg Margarite)