Ontogeny of postural regulation during manual carrying. The immobilization times (black filled circles in (A), (C), (D)) from PND 0 to PND 20 are the same as in Figure 3C and shown as a reference. (A) The mean ± SEM immobilization times that the pups maintained their specific hindlimb postures of extension (magenta triangles), half flexion (green squares) or full flexion (blue filled squares) are shown. (B) Comparison of the hindlimb postural types of PND 6, 10 and 14 pups. The postural types are categorized into five types: extension (magenta), half flexion (green), full flexion (blue), full to half flexion (gray) and others (white). The number of tested pups is provided in the parentheses. **p < 0.01. (C) The mean ± SEM immobilization times with an extended forelimb posture (magenta triangles) or a flexed posture (blue filled squares) are shown. (D) The mean ± SEM immobilization times with a forward (magenta triangles) or downward (blue filled squares) directed tail posture are shown. n ≥ 18 in each PND in (A), (C), (D).