Standing up: a simple challenge of integrating the perception of gravity with action

Many, if not most land-based vertebrates have an innate capability to stand after birth. This skill most likely involves the integration of perceiving gravity with the action.

• Looking from the front, we see how the centre of gravity is supported by the feet on either side.
• Looking from the side, we see how the centre of gravity is supported by the feet in front and behind.
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• the centre of gravity has to be above a small area defined by the feet, for the pose to be stable.
• during the process of standing up, the trajectory of the centre of gravity cannot go outside of that small area.
• It seems very likely that all species with the innate skill to stand up also have an innate capability to perceive gravity.

It seems likely that there is also some feedback process so that if the centre of gravity comes close to the boundaries of the support area, automatic corrective action is invoked.