Around 140 goats have been deployed to a San Francisco hillside in an effort to fight future fires.

The herd spent most of the day at Rincon Hill Dog Park close to where the Bay Bridge begins for Caltrans, finishing their feasting activities at around 3:30 p.m. Wednesday.

Goats are a natural fit for wildfire prevention because of their ability to graze in steep spots that are difficult for machines to reach—making them an especially good choice for the hilliest city in the United States.

The firefighting effort usually takes place twice a year and helps remove brush to reduce fire dangers.

READ MORE: Meet the Firefighting Goats Helping to Mitigate San Francisco’s Wildfire Risk

“Caltrans is using goats to eat grass and brush as a means to reduce fire danger from vegetation that will turn dry and brown later this year. Caltrans uses goats to control brush in hard-to-reach places—areas that are difficult to reach with mowers or weed whips,” a Caltrans spokesperson said.

The goats are strong and agile, able to climb steep grades and scamper over rocks and other obstacles, which makes them ideal for the steep hillside at the dog park.

“In addition, they are environmentally friendly, obviating the need for herbicides, leaving behind only their droppings, which happen to be good fertilizer,” the spokesperson said.

Caltrans hired the goats through a herding company to remove the brush, but did not specify which company.