Disambiguating grappling: Push-pull tangle as an intriguing social interaction in spider monkeys

Area of Science:

• Primate ethology
• Animal behavior
• Primate social interactions

Background:

• The term "grappling" in spider monkeys (Ateles spp.) ambiguously refers to play, aggression, and a distinct non-aggressive interaction.
• Previous descriptions lacked clarity, necessitating a re-evaluation of specific social behaviors.

Purpose of the Study:

• To document and characterize the behavioral elements of a specific non-aggressive spider monkey social interaction.
• To propose a new term, "push-pull tangle," to distinguish this interaction from play and aggression.

Main Methods:

• Observations were conducted on Geoffroy's spider monkeys in Mexico and Colombian black-faced spider monkeys in the UK.
• Detailed behavioral elements of the interaction were recorded ad libitum across wild and zoo settings.
• Approximately 800 hours of observation in Mexico and 300 hours in the UK yielded 13 and 12 bouts, respectively.

Main Results:

• Consistent behavioral elements were observed across both species, including face greeting, mutual embraces, and genital touching.
• The interaction, termed "push-pull tangle," was characterized by prolonged bouts.
• Observed interactions between adults were neither aggressive nor playful.

Conclusions:

• The renaming of the interaction to "push-pull tangle" clarifies its distinct nature.
• This refined terminology aids in differentiating between various spider monkey social behaviors.
• The study provides a more precise understanding of primate social dynamics.