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Monkey foot study complicates assumptions about early human ancestor locomotion

Researchers found wild mangabeys climb vertical trunks using midfoot flexibility, challenging fossil movement models.

The short version

  • Video analysis of wild sooty mangabeys showed their midfeet flex up to 46 degrees during vertical climbing.[ScienceDaily]
  • The finding suggests primates do not require ape-like flexible ankles to effectively climb vertical tree trunks.[ScienceDaily]
  • Researchers note that more fossil discoveries are required to determine the physical anatomy of the human-chimpanzee common ancestor.[ScienceDaily]

Key facts

  • Wild sooty mangabeys demonstrated up to 46 degrees of midfoot flexion while vertically climbing tree trunks in Ivory Coast.[ScienceDaily]
  • Chimpanzee ankles can flex upward by roughly 45 degrees when climbing, whereas human ankles typically flex about 20 degrees.[ScienceDaily]
  • Humans and chimpanzees diverged from a shared common ancestor roughly 6 to 7 million years ago.[ScienceDaily]
  • Climbing proficiency in modern human foragers is thought to depend heavily on soft tissue like ligaments, tendons, and muscles rather than bone structure.[ScienceDaily]

What remains uncertain

  • Whether the last common ancestor of humans and chimpanzees had foot anatomy resembling modern apes or modern monkeys remains unknown pending further fossil evidence.[ScienceDaily]

Sources

Outlet counts describe coverage, not independent confirmation. Reports may share a wire service or original source.