Tactical deception to hide sexual behaviour: macaques use distance, not visibility

Area of Science:

• Primate behavior
• Ethology
• Animal cognition

Background:

• Tactical deception (TD) is hypothesized to play a role in concealing sexual behavior.
• Cognitive mechanisms for TD range from no deception to complex strategies like visual perspective taking (VPT).
• Macaques exhibit VPT in other contexts, suggesting potential for advanced TD during sexual interactions.

Purpose of the Study:

• To investigate the specific tactical deception strategies employed by macaques to hide sexual behavior.
• To determine if macaques utilize TD level 1.5 (involving VPT) or TD level 1 (creating distance).
• To examine the role of hiding screens in facilitating TD during sexual interactions in two macaque species.

Main Methods:

• Observational study of captive groups of *Macaca mulatta* and *Macaca fascicularis*.
• Introduction of temporary hiding screens to assess their use during sexual behavior.
• Analysis of spatial positioning during sexual interactions relative to the dominant male.

Main Results:

• Sexual behavior near screens was infrequent, and not systematically hidden from the alpha male, ruling out TD level 1.5.
• Both females and non-alpha males increased their distance from the alpha male during sexual interactions, consistent with TD level 1.
• The use of peripheral locations (TD level 1) appears to be a primary strategy for enhancing mating opportunities.

Conclusions:

• Macaques primarily employ TD level 1, creating distance from the dominant male, to conceal sexual behavior.
• Evidence does not support the use of higher-level TD, such as VPT (TD level 1.5), in this context.
• TD level 1 strategies, like occupying peripheral locations, are likely effective for increasing sexual access in many species.