A hilarious video has emerged from the US of a mother freaking out when she sees a bison ambling towards her vehicle.

The footage, captured at the Yellowstone National Park by her son, shows the woman going into hysterics while the large bison saunters past.

The woman can be heard screaming "nooooo!" as the animal makes its way past the car in an unthreatening and leisurely manner.

"With any other person it would have been a quiet moment, instead it was full of my mom screaming and both of us telling each other to shut up," her son wrote online.

This video was taken last month in Yellowstone National Park in Wyoming. I was on a cross country road trip with my mom. Basically we had just gotten dinner and were headed back to our campsite when we noticed this slow moving bison walking towards the car in front of us. With any other person it would have been a quiet moment, instead it was full of my mom screaming and both of us telling each other to shut up.