Extended Data Fig. 7: Histogram of Mahalanobis distances between the mean unshod human footprint and resampled unshod human footprints (gray) and chimpanzee footprints (yellow).
From: Footprint evidence of early hominin locomotor diversity at Laetoli, Tanzania
As in Figure 3c, blue, orange, and green dashed lines represent samples from Laetoli G1, S1, and A, respectively. Only Laetoli A is labeled, for clarity. Sample sizes for these samples as in Fig. 2c as well. The black dotted-dashed lines have been added to represent the average cross-stepping footprints produced by 10 adult habitually shod humans. All fall squarely within the distribution of unshod human footprints (probabilities of sampling tracks like these range from 0.20 to 0.94), and a great distance apart from the Laetoli A sample (green). Human cross-stepping footprints tended to be slightly closer to the human mean than the Laetoli S1 and G1 samples, but their distribution does overlap with the Laetoli S1 sample and with some of the Laetoli G1 samples. Cross-stepping footprints fell, on average, a Mahalanobis distance of 27.2 farther from the human mean than their “normal” walking counterpart.
