A New Experimental Protocol for Assessing Hominoid Assisted Arboreal Bipedalism

Area of Science:

• Primate locomotion
• Evolutionary biology
• Biomechanics

Background:

• Arboreal bipedalism is a proposed precursor to hominin terrestrial bipedalism.
• Observing and studying this behavior in natural settings is challenging due to its rarity and difficulty in observation.
• Existing captive studies have yielded limited data on arboreal bipedalism.

Purpose of the Study:

• To present an experimental design and protocol for collecting video data on arboreal bipedalism in captive primates.
• To increase the frequency of observing this rare behavior.
• To enable qualitative and quantitative gait data extraction for biomechanical analysis.

Main Methods:

• Developed a simulated arboreal foraging scenario using parallel PVC tubes and food rewards.
• Utilized five GoPro cameras for comprehensive video data collection.
• Collected data on six adult chimpanzees (3 males, 3 females) at a French primate park.
• Validated the experimental design by identifying successful and unsuccessful interactions.

Main Results:

• The experimental design successfully elicited arboreal bipedalism in all chimpanzees.
• Full strides were observed, allowing for gait parameter analysis.
• Two distinct forms of arboreal bipedalism were identified: forward-facing and sideways.
• The protocol demonstrated suitability for gait analysis and interspecies comparisons.

Conclusions:

• The developed protocol effectively increases the frequency of arboreal bipedalism in a controlled setting.
• This method provides valuable data for detailed biomechanical investigation of arboreal bipedalism.
• The findings contribute to understanding the role of arboreal bipedalism in the evolution of hominin bipedalism.