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Secular trend in body weight is an indicator of environmental adaptation and changes in nutrition and health over time. In this study, we examined body weight of Macaca mulatta from Cayo Santiago to investigate how body weight changed in past 80 years. Rhesus macaques were introduced from India to the Caribbean island in 1938, and the colony history was characterized by fluctuations in resource provisioning, population dynamics, and medical care, in addition to acclimation. We collated body weight data of 921 females and 1202 males born between 1938 and 2009, collected by researchers between 1956 and 2014. All subjects were categorised by sex, partitioned into five period cohorts based on colony conditions at the time of their birth (1938-55, 1956-68, 1969-74, 1975-83, 1984-2009), and body weights for each cohort were calculated at different age-intervals (yearly from 0-1 to 5-6, then 6-10 and 11-15). Results revealed that overall, males and females alike, in early age-intervals (0-4 years), the 1938-55 cohort had the lightest body weight, while in the young adulthood age-intervals (6-10 years) the 1969-74 cohort had the heaviest body weight. This latter cohort experienced low population densities, unlike subsequent generations (1975-83), and a protein increase in provisioning relative to previous generations (1956-68). However, the most recent cohort (1984-2009) displayed the lowest mean body weights across almost all age-intervals, despite them receiving a tetanus vaccine (hence longer expectancy), annual population culling and regular provisioning. Further investigation is warranted to differentiate the effects of different environmental factors on the Cayo Santiago colony.
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Coming to the Caribbean—acclimation of Rhesus macaques ( Macaca mulatta ) at Cayo Santiago
Abstract ObjectivesTo investigate whether the Cayo Santiago, Puerto Rico (Latitude: 18.1564°N; temperature range 19°C to 32°C) rhesus macaque population has acclimated to their tropical island conditions since arriving from Lucknow, India (Latitude: 26.8470°N; temperature range 8°C to 41°C) in 1938. Materials and MethodsUsing the derived skeletal collection, measurements were taken of long bone lengths, diaphyseal circumference, and body weight using 635 (237 males and 398 females) skeletally mature individuals. Measurements sampled colony members born over a 51‐year time span at Cayo Santiago, from 1951 to 2002. ResultsResults demonstrated that body weights and diaphyseal circumferences significantly declined in both males and females. Long bone lengths relative to body weight and diaphyseal circumference also increased in females. Whereas body weight, long bone length and diaphyseal circumference declined at near parallel rates in males. DiscussionThe population has acclimated to homogenous, tropical, conditions of the Caribbean island since their arrival over 80 years ago. Trends in both sexes aligned with Bergmann's rule, though females displayed a greater decline in body weight, as well as greater affinity with Allen's rule, than did males. Buffering effects related to male competition may be responsible for this discrepancy. Overall, the Cayo Santiago populations, as shown over a significant period (1951–2002) of their history, have acclimated to their island conditions by decreasing in size and altering body proportions.
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- Award ID(s):
- 1926601
- PAR ID:
- 10414190
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- American Journal of Biological Anthropology
- Volume:
- 181
- Issue:
- 2
- ISSN:
- 2692-7691
- Page Range / eLocation ID:
- p. 271-295
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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