Effect of the forces at the mouth and tail.

A: measured maximum forces at the mouth and tail. B: torque generated by the forces at the mouth and tail. The torque of the mouth (τM) and tail (τT) were calculated as the product of maximum force and the length from foot to mouth and tail. Furthermore, mghθmax was the torque required to maintain stability in the most inclined posture θmax. The torque ratio is the ratio between the torque generated by the force at the mouth or tail and the torque required for stable standing (100τM/mghθmax and 100τT/mghθmax, respectively).