To climb down trees, primates adopt upright postures
Paris,
Life
While the ability to climb trees has often been studied in arboreal mammals, descending is a far more complex task, as it requires control of balance, speed and posture. A team of scientists led by a CNRS researcher1 shows that arboreal primates display a wide diversity of vertical descent strategies, frequently adopting upright postures, unlike other mammals that mostly descend head first. These findings will be published in eLife on 17 February.
- 1 Working at the Center for Research in Paleontology (CNRS/French National Museum of Natural History/Sorbonne University).
The researchers found that arboreal primates use a greater variety of descent postures than other mammals, often upright, relying on asymmetric gaits that allow them to maintain both speed and stability. Three types of descent were identified: head first, which concerns the majority of non-primate mammals; sideways; and head-up descents. Each is associated with specific speeds and modes of locomotion. These strategies are closely linked to morphological characteristics such as limb length, tail length and relative head size. They also suggest that early primates were already using vertical postures when moving through trees. This work is based on analyses of nearly 1,400 descents and 1,400 ascents in 57 individuals belonging to 21 species of primates, rodents, carnivores, marsupials and treeshrews, as well as 13 fossil species of primates and closely related early relatives dating back approximately 65 to 50 million years.
This study provides new insights into the evolution of primate locomotor abilities and highlights the importance of morphology in vertical descent. It opens up new perspectives for the study and interpretation of fossils and could also inspire the design of robots capable of moving along vertical structures.
Bibliography
Kinematics and morphological correlates of descent strategies in arboreal mammals suggest early upright postures in euprimates. Séverine LD Toussaint, Dionisios Youlatos, John A Nyakatura. Elife. 17 February 2026.
