Britannica Sources used in this answer

How did the pelvis of Ardipithecus support both climbing and bipedal movement?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

skeleton of “Ardi” — Ardipithecus Reconstructed frontal view of the skeleton of “Ardi,” a specimen belonging to the early hominid species *Ardipithecus ramidus*.

The pelvis of Ardipithecus ramidus exhibits a unique anatomical mosaic that facilitated both bipedalism and climbing.1

To support bipedal movement, the pelvis featured a short but broad upper blade (ilium) oriented from front to back, with the hip joint positioned near the level where the backbone joins the pelvis. These characteristics, which allowed for a flexible lower back, are recognized markers of bipedal locomotion also found in later hominins and humans.12

Simultaneously, the lower portion of the pelvis remained distinctly apelike. It possessed a strong posterior and inferior projection known as the ischium, which served as an anchor for the powerful muscles required for climbing. This combination of features allowed Ardipithecus to maintain a bipedal posture while retaining the physical capabilities necessary for arboreal activity.12