More than a hundred goats have descended under the Interstate 5 Ship Canal Bridge, using four-hoof drive to clear vegetation from the right of way.

The voracious eaters, hard at work for the Seattle Department of Transportation, began last Friday and will be there through Monday, according to spokesperson Alison Lorenz.

The 115 ungulates are advantageous for the job since they can navigate steep slopes that people and equipment cannot easily or safely reach. They’re also an environmentally friendly alternative to herbicide, Lorenz said.

The Vashon Island company “Rent-A-Ruminant” is supplying the goats to do the heavy munching.

In the 15 years the company has worked with SDOT, the goats have sampled vegetation across the Emerald City including the Pine Street Hill Climb stairs, the Jose Rizal Bridge and the Alaskan Way Viaduct. In 2007, the University of Washington hired the goats to address a hillside overgrown with blackberry bushes and English ivy.

According to the company’s website, the company was founded in 2004 with only 10 goats and has now grown to 120 goats — all rescues.

Prior to the goats arriving to a worksite, the location is examined to ensure there are no hazardous or poisonous plants. Goats are ruminants, which are mammals that get nutrients from plants by fermenting it in their specialized stomach. They don’t spread bad plants, because weed seeds are sterilized during the digestive process.

A fence is being used to keep the goats from wandering too far, and they are being supervised by their herder, Tammy Dunakin.