Okay seriously, humans are not actually cats. But, humans and cats do share similar nervous system control over how we move from one place to another, i.e. locomotion as described in a recent review article published in Physiology. The ability for mammals to finely control movement depends on two main control systems located in the brain and spine as well as sensory feedback from the skin, muscles, tendons, eyes, and ears. The ears contain a special sensory organ that allows us to detect our position in space, head position, as well as motion. While movements like walking and running are performed automatically (without having to consciously think about moving each body part), it is the sensory feedback that helps us to avoid obstacles, correctly position our feet, and refine our movements.
Cats in particular are rather nimble creatures that are well-studied for their amazing control over locomotion – most of the time, as shown in this NatGeo video from YouTube:
The scientists in the article reported that the skin on our hands and feet provide critical sensory feedback information about the surfaces we are moving on (ex: walking on sand vs. cement). This feedback helps us adjust our movements accordingly to maintain stability. The pattern of sensory receptors are quite similar between humans and cats, which is what led the scientists to describe humans as “upright-walking cats”. In fact, activation of different regions of the human foot results in different corrections – more or less flexed, left or right rotations, etc. In the article, Drs. Pearcey and Zehr state that, “the foot acts to gather tactile information – as does an antenna – and provides feedback to guide the limb perturbations and to maintain forward progression during walking.” In this way, our feet help prevent tripping or stumbling.
I never thought of the human foot as an antenna before. I think my foot antennae might be broken as I am rather clumsy.
GEP Pearcey, EP Zehr. We Are Upright-Walking Cats: Human Limbs as Sensory Antennae During Locomotion. Physiology. (5): 354-364, 2019. https://doi.org/10.1152/physiol.00008.2019.