Wild Tibetan Macaques Use a Route-Based Mental Map to Navigate in Large-Scale Space

Area of Science:

• Primate behavior
• Spatial cognition
• Animal navigation

Background:

• Nonhuman primates face challenges in resource acquisition due to spatial and temporal distribution.
• Understanding primate spatial memory and navigation strategies (route-based vs. coordinate-based) in large-scale environments is crucial.

Purpose of the Study:

• To investigate spatial memory and mental map formation in wild Tibetan macaques (Macaca thibetana).
• To determine if macaques use route-based or coordinate-based navigation in a mountainous, forested ecosystem.

Main Methods:

• Utilized instantaneous scan sampling and GPS tracking over 214 days (September 2020 - August 2023) on Mt. Huangshan, China.
• Recorded behavior and locations of macaques, obtaining 7180 GPS points.
• Analyzed reused route segments, nodes, and travel directions to infer navigation strategies.

Main Results:

• Tibetan macaques reused 1264 route segments and 48 nodes, indicating habitual travel paths.
• Route segment usage was influenced by resource availability, terrain roughness, and vegetation density.
• Macaques approached revisited sites from limited directions and deviated from straight-line paths, suggesting route-based navigation.
• Travel distances averaged 24% longer than straight-line distances to revisited sites.

Conclusions:

• Tibetan macaques employ a route-based mental representation for navigating large, complex montane forest habitats.
• This navigation strategy aids in locating food resources within heterogeneous environments.
• Findings challenge the assumption of coordinate-based navigation in primates for large-scale spatial tasks.