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May 7, 2012

Op-Ed: Energy Cycles: Nadja Spiegelman Explains the Creation of Zig and Wikki’s Latest Book


“So I want you to write an early reader children’s comic book about the nitrogen cycle and how all things in nature are symbiotically interconnected,” my mother (and editor at TOON Books), Francoise Mouly, said to me on the phone. I’d been trying to write about recycling: Alien pals Zig and Wikki land in a recycling binwhat happens next?! But the What Happens Next was simply too depressing (they get shipped overseas and sold to China, who then sells them back to us as manufactured recycled goods, wasting an enormous amount of energy in the process). Somehow, the nitrogen cycle seemed easier to explain.

I began searching the internet for a solid circle of energy. I wanted an ecosystem that was diverse, clearly interdependent, and self-contained. I looked in the jungle, in the Sahara, under the sea, and on mountaintops. The first Zig and Wikki book had the two aliens discover the concept of a food chain by a swamp, and I wanted this second book to be clearly different. When I hit upon dung beetles, I knew I had found boy-book gold. So I worked my way backward from there (literally), and found myself reading article after article about the cow’s digestive process. And that’s where I got really hooked.
Cows are ruminants, which means they are among the few animals on Earth that can extract energy from the cellulose in grass. But newborn calves cannot. Through their mother’s milk, young calves acquire an interior ecosystem of millions of microorganisms in their stomachs. Then and only then do they begin eating grass. The microorganisms live and multiply and die in the cow’s rumen, breaking down the cellulose, and it is in part through digesting the carcasses of the dead microorganisms that the cow acquires protein. And because of this complex digestive process, cow manure remains fertile and packed with energy. The dung beetles roll it up into balls and bury it under ground then lay an egg in each dung ball. When the baby dung beetles are born, they sustain themselves on the dung until they are large enough to dig their way out into the world. The dung beetles’ tunnels aerate the soil and the cow manure buried underground returns energy to the grass through its roots. It’s a beautiful, symbiotic circle of energy. Now I just had to make sure I had my facts straight and explain it all to six-year-olds.
I had a very specific desire for the narrative – I wanted one of my aliens, Zig, to spot a dung beetle on a cow patty, then follow it as it rolled a ball of dung away to its tunnels. I also wanted to show a cutaway of the sophisticated network of tunnels that the beetles had created underground. But I wasn’t sure if the science was on my side. There are three distinct types of dung beetles—rollers, tunnelers, and dwellers. Rollers roll away the dung then bury it, tunnelers dig directly beneath the patty, and dwellers live within the patty itself. I was able to find that tunnelers create a network of tunnels, but did rollers as well? I searched until I reached the limits of the internet (The internet often seems endless, and I’d only reached that wall once before, when looking for an image of an Ewok in a sexy catholic school girl costume—long story). Anyway, I picked up the phone and called Doug Emlen at the University of Montana, one of the preeminent researchers of dung beetles. To my surprise and infinite gratitude, he spoke with me and answered all of my questions. Rollers do NOT create a system of tunnels; they dig a single tunnel and a crypt. It seemed I had to choose—follow the roller, or show the network of tunnels. But then my collaborator on Zig and Wikki, the incredibly talented cartoonist Trade Loeffler found a solution in the composition of the page that let me have my cake and eat it too:

Throughout the back and forth of our collaborative process, Trade and I sent each other countless links and photos. I remember one time in particular, right as Trade was coloring a sequence where Zig and Wikki actually go inside the cow, I stumbled across an incredible photo essay on the blog Throwback at Trapper Creek filled with gruesomely beautiful images of a cow being butchered in a field. I emailed him these ones below with the note “It’s green inside!!!” and he added the green grass into this sequence at the last minute.

Above three photos from the Matron of Husbandry blog.

While researching the book was fun—we got a tiny toy model of a cow to study all the anatomy and watched documentaries on dung beetles to see how they moved—it’s nothing compared to getting feedback now that it’s out in the world. One reviewer, Rod Lott at, wrote in to say, “I read it to my six-year-old last night as his bedtime story. He laughed so hard at the inclusion of the word "poop" that he wet his pants a little.” When the book finds its way into the hands of the perfect audience, that’s when the circle of energy is truly complete.