Scientists say that the first vertebrates to walk on our planet may have done so in the depths of the oceans millions of years before they moved to land. In 2018, scientists discovered that miniature skifish and some basil sharks were essentially able to walk across the ocean floor using some of the same nerve circuits that we use for walking today. It was common for vertebrates to only learn to walk when they began to leave the sea for Earth about 380 million years ago.
However, New research Models based on small sledfish, one of the most primitive vertebrates, show a much older origin of some walking mechanisms that could be more than 400 billion years old. The researchers used published video data on the rapid dynamics of small sled fish, and mathematicians developed a model to investigate how leg-like movements evolved in the deep sea.
The model created by mathematicians is very simple and predicts the most efficient, controlled and balanced gait in a neutrally thriving environment. The model found that the best results required an alternating pattern between the left foot and the right foot, similar to how a young ski moves. The researchers also found that the movements of the young fish do not require any additional energy cost and can be enhanced over time with a simple instructional scheme.
Ultimately, the researcher’s model led to the understanding that despite a wide range of gait that could be used, the foot control strategy could be detected by alternating left and right and would be discovered and the optimal solution for energy and movement efficiency. The researchers also noted that only primitive legs would be required to achieve the pattern of placement. Once the two-footed flippers developed, the creatures would need only minimal control of their neurons to achieve walking on land.