California is suffering one of its worst summers for wildfires in recent memory. There are dozens of fires burning in the Golden State, and some won't be fully extinguished until the winter.

It is an expensive business for a state that is suffering a serious financial crisis. But California has a little-known secret weapon when it comes to fighting fires. It's the pack mule, which the US Forest Service has used for decades to haul equipment and vital supplies in remote mountainous areas.

The mules cost significantly less than mechanical equipment, including helicopters, which are often used to do the same job. Sometimes the animals can get to parts of the wilderness that would be otherwise impossible to access.

But despite the fact that pack animals offer value for money, the use of mules is on the decline.

Michael Morse, Packstock Coordinator for the US Forest Service in Mammoth Lakes described to Peter Bowes the hard work and value of the mules.

Video shot and edited by Bryan Darling