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Body mass in lowland gorillas: a quantitative analysis.
1Department of Anthropology, University of California, Santa Cruz, California 95064, USA. zihlman@cats.ucsc.edu
American Journal of Physical Anthropology
|August 23, 2000
Summary
Gorilla body composition shows less sex difference than body weight suggests, with males having more upper body muscle. Age and health impact tissue distribution, particularly in females.
Area of Science:
- Primatology
- Comparative Anatomy
- Bioanthropology
Background:
- Gorillas exhibit significant sexual dimorphism in body weight and canine size.
- Understanding tissue composition is crucial for comparative studies of hominoids.
Purpose of the Study:
- To determine body proportions and tissue composition in lowland gorillas.
- To analyze variations based on age, sex, and life history.
- To compare gorilla body composition with other hominoids.
Main Methods:
- Dissection of four adult captive lowland gorillas.
- Analysis of relative contributions of bone, muscle, and adipose tissue to total body mass.
Main Results:
- Bone mass contribution is consistent (10.2-13.4%) across a wide weight range (99.5-211 kg).
- Muscle comprises ~37.3% of body mass in most individuals, while body fat ranges from 19.4-44%.
- Males show greater upper body muscle mass, particularly in forelimbs, compared to females.
Conclusions:
- Gorilla tissue composition differences are less pronounced than body mass dimorphism.
- Age and health conditions (e.g., arthritis, obesity) significantly influence individual body composition.
- Gorillas possess more muscle and less adipose tissue than orangutans, with distinct limb proportions.
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