Hand Preference during Tool Use in Wild Bearded Capuchins

Area of Science:

• Primate behavior
• Animal cognition
• Neuroscience

Background:

• Limb preference, or lateralization, reflects brain functional asymmetries and is common in humans.
• While handedness is debated in non-human vertebrates, tool use is a potential driver.
• Wild capuchins (Sapajus libidinosus) inhabit the Caatinga forests of Brazil.

Purpose of the Study:

• To investigate hand bias during tool use in wild capuchins.
• To determine if tool type influences hand preference.

Main Methods:

• Observation of feeding tool use in wild capuchins.
• Categorization of tools into probing, pounding/cracking, and digging types.
• Recording hand use in 118 tool use bouts.

Main Results:

• Different tool types exhibited varying motor demands.
• Digging tools appeared to favor right-hand use.
• A potential right-hand bias was observed, particularly with digging tools.

Conclusions:

• Tool use in capuchins may contribute to limb lateralization.
• The harsh Caatinga environment could exert selective pressure favoring tool use and laterality.
• Further research with larger sample sizes is required to fully evaluate right-handedness in tool use, especially for digging.