Evolution of Tree Climbing in Chameleons

A study published in BMC Evolutionary Biology explores the exceptional tree-climbing ability of chameleons, revealing that their ball-and-socket joints in wrists and ankles play a crucial role in their arboreal lifestyle. Researchers found that chameleons have twice the number of skeletal elements in their wrists and ankles compared to previously thought, allowing for greater rotation and grip strength.

Key Findings:

• Chameleons possess two-toed feet, which are actually bundles of digits bound by connective tissue, enhancing precision and mobility in trees.

• Larger, more evolved tree-climbing chameleons have up to eight skeletal elements in their wrists and ankles, while earlier diverged species (ground and bush climbers) have only four.

• The ball-and-socket joint adaptation enables better wrist flexion, providing a biomechanical advantage for climbing.

This study deepens our understanding of chameleon evolution, showing how skeletal adaptations allowed them to transition from ground-dwelling to tree-dwelling species.