"One morning the Wumps were awakened by a far-off humming sound. It seemed to be coming from somewhere above, and as the humming grew into a heavy roar, the sleepy-eyed Wumps crept through the trees for a peek at the sky. Zooming straight for the earth came a great flock of potbellied monsters, with tails and fins, spitting fire and shooting out streaks of black smoke."

This is the second book designed to raise awareness of environmental problems. The first environmental picture book for children was Farewell to Shady Glade, published in 1966. A year after the Wump World was published, the Dr. Suess book "The Lorax" was published. There are interesting parallels in "The Lorax" to both "The Wump World" and "Farewell to Shady Glade". "Capyboppy" the capybara had some influence on the design of the wumps.