Hora del parto en Daimiel (Ciudad Real) en la primera mitad del siglo XIX

Abstract

Human beings are descended from ancestral primates of very small body size (barely 20 grams), which about 65 million years ago inhabited the canopy of vast planetary forests. We were then very peculiar mammals, distinguished notably by our visual specialization (at the expense of smell) and by retaining the archaic pentadactyl structure (hands and feet with five fingers, like amphibians and reptiles) but with nails instead of claws and with the ability to grasp. These characteristics were associated with our lifestyle at the time: nocturnal hunters lurking for insects and other small prey, captured with our prehensile hands and thanks to our binocular vision. The visual development and the gripping and manipulation ability endowed primates with extreme motor coordination and manual dexterity. These qualities drove ancestral primates towards maximal brain development among mammals, providing them with precise information about the external environment and its objects, which would later become the biological basis for conceptual thought in our species millions of years later. Keywords: Human evolution, Primate characteristics, Brain development, Nocturnal hunting, Visual specialization.