Calculate centripetal acceleration for circular motion using a=v^2/r This acceleration will be what you call a 'g' force.
Pilots and astronauts are spun round in centrifuge type contraptions to see how they cope with g forces. Mere mortals tend to pass out at 5-7 g, but with training, an inflating suit, and a good genetic mix to help you cope, 11 g or more is possible. The Airforce in many countries now check their candidates for genetic ability to cope with g forces before deciding wether to train them or not!
By 'guestimating' the speed at which an animal runs and the radius of its turning circle, you can calculate its g force.