I was watching this video which reports on studies of the force involved when moles dig in soil.
At around 0:30 seconds into the video you can see the mole typically pulls its paws back into the space which has been created by making a tunnel and then thrusts them forwards into the soil before pulling to the side, does anyone have an estimate for the speed at which its thrusts its claws forwards into the soil in the initial part of the digging motion?