oats are one of the oldest domesticated species. For thousands of years, they've been used for their meat, milk and hair. They've even pulled carts. And now they have a new job ? on the front line of the fight against an invasive pest plant.  Erika Celeste reports from Chattanooga, Tennessee.

Chattanooga city officials have hired some rather unusual workers for the area's most difficult landscaping jobs.

Winter, Pita, Indiana and Lily are goats? and they are in charge of clearing an invasive plant known as kudzu from a park on Lookout Mountain.  Surrounded by an electric fence and guarded by a Great Pyrenees watch dog named Goliath, they will be hard at work for a month? about all the time it will take them to clear half a hectare.

The goats belong to Natural Landclearing, owned by Steve Surowitz and his wife Marci. The company's herd contains about 100 animals, most of which are fainting goats. This species has a genetic disorder that causes their muscles to freeze for a few seconds when they're startled, so they fall down. Surowitz explains that makes them better for a land clearing operation. "They don't challenge the fence, they don't run away and if they do, you just clap your hands and they faint," he says with a laugh.

The plant that ate the South

Like much of the South, Chattanooga suffers from near strangulation by kudzu. The Asian vine was brought to the United States more than a century ago, and widely promoted as an effective way to reduce soil erosion. But it was too effective; it can grow up to 36 centimeters a day, quickly blanketing everything from telephone poles and houses to hillsides and trees. It became known as 'the plant that ate the South' and was declared a pest plant in 1953. Millions of dollars are still spent each year to try to control it.

Donna Hertlein is executive director of the Lookout Mountain Conservancy, which hired the goats to clear the park. She says in the battle against kudzu, they need every tool in their arsenal to win. She explains that controlling it is an enormous challenge. "It is enormously expensive to try to rid an area of kudzu, which is one of the reasons why it continues to eat the south.  Ridding an area of it is cost prohibitive for a lot of folks."

The modern practice of using goats to clear land first gained popularity out West, in places like California, where dry brush commonly fuels wildfires. Goats, which eat almost anything, especially like brush and shrubs, but a taller plant doesn't faze them. Steve Surowitz says although kudzu can climb to several meters in height, the goats do a surprisingly good job of pulling it down. "They'll stand on their hind legs and eat up to [2 meters] tall.  So goats naturally do this. What they don't like, they won't eat. It's as simple as that. If they know it's poisonous, they won't eat it."

Surowitz admits that if they know it's good to eat, they will try to eat it, and this is one of the drawbacks to using goats. "If you've got a tree or something to that effect that you want to protect, you better have a three foot barrier around it, otherwise a goat will stick its head through, push it over, lean on it, whatever it can to get to the greens on the tree!"

Only phase one of the land clearing mission

Goats can't do the job all by themselves. Once they clear away the vines, Surowitz says it's time for the humans to step in. "If you don't have a plan in place for when they're done, what they've done will get wasted away again and it will turn right back in to what it was," he stresses. "So the goats are in no way a permanent repair."  With the ground cover gone, it becomes much easier to identify the kudzu's root crown system and attack it directly with chemicals so it can't re-grow. 

Goats have been so successful in helping Chattanooga control its pest plant problem, the city held a Goat Browsing Academy last year to train local residents to care for land-clearing goats of their own. Donna Hertlein explains it was a hands-on workshop that covered the basics of goat management. "Since they established that ? you can get goats through [the folks who have gone through the Goat Browsing Academy] to help you with your exotic pest plant issues."

Winter, Pita, Indiana and Lily, along with the goats that havegraduated from the Browsing Academy, have been used not only for city and land trusts, but also at private homes around central Tennessee. 

The Surowitz's plan to start using larger herds to clear areas in less time. They also hope to get their goats onto some military bases in the South, which are also losing the battle with kudzu.