For an average lawn, a mower works just fine, but for fire-prone slopes or polluted landfills, an increasing number of cities are turning to a rugged biological machine: the goat.

The sure-footed creatures pack a world-renowned four-chambered stomach that allows them to devour tree bark and magazines as easily as you nibble lettuce. Key to the process is the rumen, which "acts as a big fermentation vat," and allows goats to selectively regurgitate food for rechewing until it can actually be digested. From this process, the goats get the ability to eat roughage and the English language received the verb "ruminate."

Now, urban and industrial sites across the country are exploiting this amazing machinery to clear their lands of unwanted vegetation without using chemicals or lawnmowers.

Dozens of services across the country allow owners of large areas of land to rent goats to reduce the amount of vegetation on their land. In San Diego, the goats clear brush that provides fuel for fires. In Denver, a herd of 100 goats is used to graze on severely degraded land and in areas where herbicides are too blunt an instrument for park management.

In this video, we visit City Grazing, a goat rental service based near Hunters Point in San Francisco. Run by David Simon, aka The Goat Whisperer, the company grazes its goats on a landfill in a heavily industrial area of the city. Don’t get fooled by the post-apocalyptic setting: this is an urban farm with a real business model.

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