Self-anointing behaviour in captive titi monkeys (Callicebus spp.)

Area of Science:

• Primate Behavior
• Ethology
• Animal Communication

Background:

• Self-anointing, the application of plant substances to the body, is observed in various animal species.
• The function of self-anointing is often debated, with hypotheses including self-medication and social signaling.
• Titi monkeys (Callicebus spp.) are New World monkeys known for their complex social structures.

Purpose of the Study:

• To document and analyze self-anointing behavior in two captive titi monkey species: Callicebus coimbrai and Callicebus barbarabrownae.
• To investigate potential drivers for this behavior, considering self-medication and olfactory communication hypotheses.
• To contribute to the understanding of primate behavior and interspecies interactions.

Main Methods:

• Observation of two captive titi monkeys (Callicebus coimbrai and Callicebus barbarabrownae) over an eight-month period (October 2013 - May 2014).
• Behavioral data collection occurred during an experimental study on gut passage time at the Getúlio Vargas Zoobotanical Park, Brazil.
• Qualitative assessment of self-anointing instances, including the plant species used (Bauhinia sp.) and frequency of occurrence.

Main Results:

• Self-anointing behavior using Bauhinia sp. was observed in both captive Callicebus coimbrai and Callicebus barbarabrownae.
• While Bauhinia contains compounds potentially useful for ectoparasite control, the behavior's link to self-medication remains uncertain.
• The high frequency of the behavior in an adult male, coupled with the presence of large chest glands in these species, suggests a potential role in olfactory communication.

Conclusions:

• The observed self-anointing behavior in titi monkeys using Bauhinia sp. warrants further investigation.
• While self-medication is a possibility, the findings cautiously suggest a link to olfactory communication, potentially related to the monkeys' prominent chest glands.
• This study highlights the complexity of primate behavior and the need to consider multiple functional explanations for observed actions.