In "Time to Eat the Dog, the Real Guide to Sustainable Living," the Vales analyzed the ingredients of pet food and how much each pet eats to determine the size of their carbon footprint, a term used to express a total amount of greenhouse gas emissions.
Those numbers then were compared to a 4.6 liter Toyota Land Cruiser driven about 6,200 miles a year, the Vales told New Scientist.com
A medium-size dog had a carbon footprint about twice the size of the Land Cruiser, while a cat's carbon footprint was about equal to a small Volkswagen, said the Vales, who specialize in sustainable living at Victoria University of Wellington. Two hamsters had the footprint of a plasma television, while a goldfish was comparable to a pair of cell phones, ABC News reported Wednesday.
Dogs and cats have such large carbon footprints because they eat so much meat, which requires large amounts of land and energy to produce.