Early Hominin Movement Patterns at Laetoli, Northern Tanzania

The site of Laetoli in northern Tanzania is famous for its preservation of 3.66-million-year-old footprint trails, among which are several belonging to an upright walking hominin (Day and Wickens, 1980; Leakey and Hay, 1979; Masao et al., 2016; McNutt et al., 2021). These footprints provide the earliest definitive evidence of bipedal locomotion in the hominin lineage and have undergone intense research (Day and Wickens, 1980; Leakey and Hay, 1979; Masao et al., 2016; McNutt et al., 2021). While much has been studied about their taxonomy and gait characteristics, researchers have not yet investigated where these prints are going. Here we show that all five hominin trails are traveling in a non-random, northerly direction. Using the original M.D. Leakey survey maps of the Laetoli site, we calculated the direction of travel for 51 footprint trails spanning 11 different taxonomic groups. The majority of the footprint trails are traveling in random directions, but all the hominins are moving north, potentially toward the water source of Paleolake Olduvai. This northward movement of the hominin footprints suggests either group travel or movement toward a common destination. These data provide significant insight into early hominin behavior and add an important layer to our understanding of the Laetoli hominins.