That old joke about the only way of outrunning a bear is by running faster than the person you're with? Yeah, that's not a joke, that's just good life advice.

This grizzly bear was caught on video running at full speed, which can be as fast as 35Mph, in a national park in Wyoming, USA. By comparison, Usain Bolt's top speed is 27Mph. So yeah, if you get chased in real life, you're pretty screwed.

If you're anything like us, you'll panic just a little when you see how this mama grizzly responds to the realisation he's being followed (we thought the video was about to go all Jurassic Park).

Via YouTube