The stumptail macaques of China

Area of Science:

• Primatology
• Zoology
• Comparative Anatomy

Background:

• Stumptail macaques (Macaca thibetana and Macaca arctoides) inhabit subtropical and tropical China.
• These species replace each other geographically from north to south.

Purpose of the Study:

• To detail the morphological, cranial, and anatomical distinctions between Macaca thibetana and Macaca arctoides.
• To compare the natural history and behavioral traits of these two macaque species.

Main Methods:

• Comparative analysis of external pelage color (neonatal and adult).
• Examination of cranial and facial morphological characteristics, including fur coverage and skin color.
• Measurement of morphometric traits (length, weight, relative limb and tail proportions).
• Assessment of skull measurements and dental morphology (canine length).
• Comparison of reproductive anatomy and observed behavioral patterns (e.g., sleeping sites).

Main Results:

• Significant differences observed in pelage color, facial features (furred vs. bald), and facial skin color dimorphism.
• Macaca thibetana generally exhibits greater average head-body length, weight, and certain cranial measurements compared to Macaca arctoides.
• Distinct variations in skull proportions, canine size, and zygomatic/bimalar breadth between the species.
• Marked divergence in reproductive anatomy.
• Similarities in general natural history despite different climatic adaptations, with notable differences in sleeping site preference (caves vs. trees).

Conclusions:

• Macaca thibetana and Macaca arctoides are morphologically and anatomically distinct species.
• These species display unique adaptations and characteristics despite overlapping ecological niches and similar general natural histories.
• Further research is needed to fully understand the nuances of their natural history and evolutionary divergence.