DOI: 10.5061/dryad.vt4b8gtss
title: Worldwide savanna monkey (Chlorocebus spp.) body measures

description: Objectives: Direct comparative work in morphology and growth on widely
 dispersed wild primate taxa is rarely accomplished, yet critical to
 understanding ecogeographic variation, plastic local varia- tion in
 response to human impacts, and variation in patterns of growth and sexual
 dimorphism. We investigated population variation in morphology and growth
 in response to geographic variables (i.e., latitude, altitude), climatic
 variables (i.e., temperature and rainfall), and human impacts in the
 vervet monkey (Chlorocebus spp.). Methods: We trapped over 1,600 wild
 vervets from across Sub-Saharan Africa and the Caribbean, and compared
 measurements of body mass, body length, and relative thigh, leg, and foot
 length in four well-represented geographic samples: Ethiopia, Kenya, South
 Africa, and St. Kitts & Nevis. Results: We found significant
 variation in body mass and length consistent with Bergmann’s Rule in adult
 females, and in adult males when excluding the St. Kitts & Nevis
 population, which was more sexually dimorphic. Contrary to Rensch’s Rule,
 although the South African population had the largest average body size,
 it was the least dimorphic. There was significant, although very small,
 variation in all limb segments in support for Allen’s Rule. Females in
 high human impact areas were heavier than those with moderate exposures,
 while those in low human impact areas were lighter; human impacts had no
 effect on males. Conclusions: Vervet monkeys appear to have adapted to
 local climate as predicted by Bergmann’s and, less consistently, Allen’s
 Rule, while also responding in predicted ways to human impacts. To better
 understand deviations from predicted patterns will require further
 comparative work in vervets.
description: The data derive from field collections made over many years using
 a common protocol: Ethiopia in 1973, Kenya in 1978-79; South Africa in
 2002–2008, and several African countries and the Caribbean in 2009– 2011
 in collaboration with the International Vervet Research Consortium
 (Jasinska et al., 2013). The International Vervet Research Consortium is a
 multidisciplinary research group that has, in addition to morphological
 variation, studied variation in patterns of growth and development
 (Schmitt et al., 2018), genetic/genomic (Jasinska, et al., 2013; Schmitt
 et al., 2018; Svardal et al., 2017; Turner et al. 2016a; Warren et al.
 2015) and transcriptomic (Jasinska et al., 2017) variation, SIV immune
 response (Ma et al., 2013, 2014; Svardal et al., 2017), hor- monal
 variation (Fourie et al., 2015), C4 isotopes variation in hair (Loudon et
 al., 2014), gut parasite and disease variation (Gaetano et al., 2014;
 Senghore et al., 2016), genital morphology and appearance (Cramer et al.,
 2013; Rodriguez et al., 2015a,b), and other biological parameters within
 the genus <em>Chlorocebus</em>. Vervet
 monkeys were trapped at locations across sub-Saharan Africa, including
 South Africa, Botswana, Zambia, Ethiopia, The Gambia, Ghana, and on the
 Caribbean islands of St. Kitts and Nevis (Figure 1). Trapping in Africa
 employed individual drop traps as described by Brett, Turner, Jolly,
 & Cauble (1982) and Grobler and Turner (2010), while trapping in
 St. Kitts and Nevis was done by local trappers using large group traps
 (Jasinska et al., 2013). Animals were anesthetized while in the trap and
 then removed to a processing area. Sex was determined by visual and manual
 inspection, while age classes were assigned from dental eruption sequences
 and based on previous observations (Table 2). All animals were weighed
 with either an electronic or hanging scale, and measured with a tape
 measure and sliding calipers. Parameters and protocols describing all
 measurements are available through the Bones and Behavior Working Group
 (2015; http://www.bonesandbehavior. org/). All animals were released to
 their social group after sampling and recovery from anesthesia.
 Observations during trapping allowed us to confirm the animals’ social
 group and local population affiliation. For the present
 study, we chose metrics representative of skeletal size (body length,
 thigh length, leg length, and foot length) and body mass from a total of
 1,613 vervets in four geographically and genomi- cally distinct
 populations: Ch. aethiops in Ethiopia, Ch. p. hilgerti in Kenya, Ch. p.
 pygerythrus in South Africa, and Ch. sabaeus on the Carib- bean islands of
 St. Kitts and Nevis (Table 3). The Caribbean populations are known to be
 descended from West African Ch. sabaeus brought to the Caribbean several
 hundred years ago (Warren et al., 2015). Of the whole sample, 288 females
 and 460 males were dentally immature. Sexual maturity is typically not
 reached in vervets until near the time of canine tooth eruption, here
 denoting the beginning of dental age 6 (Cramer et al., 2013; Rodriguez et
 al., 2015a); although somatic and skeletal growth often continues beyond
 the emergence of the third molar, which is here denoted as adult (Bolter
 & Zihlman, 2003). As is common, dental age and skeletal age are
 presumed to be similarly cor- related across the genus, meaning that
 comparable dental age implies comparable skeletal developmental age across
 populations (Seselj, 2013). All measurements were
 developed by CJJ and TRT and other measurers (CAS and JDC) were trained
 directly by TRT. During training, repeated measures of the same individual
 were conducted in tandem with TRT until concordance was reached.
 The location of each trapping site is reported in decimal degrees
 (Table 1), and for most sites measured using hand-held GPS units. For
 those trapping sites lacking GPS readings, a general latitude and longi-
 tude for the trapping area (e.g., game reserve, town) was used. Human
 impact at each trapping location was assessed according to conditions
 during the time of trapping using a previously published index devel- oped
 by Pampush (2010) to study variation in vervet body size, and subsequently
 used by Loudon et al. (2014) and Fourie et al. (2015) (Table 1). This
 index includes presence/absence measures of reliable access to (1)
 agricultural land, (2) human food, (3) rubbish or garbage dumps, and (4)
 whether animals are regularly provisioned, as well as a three-level scale
 of human activity within the presumed home range of the group (low,
 moderate, or high). In the index, point values are assigned to each value,
 with the lowest tier of human impact each receiving a 1, scaling up by 1
 for each level. Added together, these val- ues comprise a human impact
 group ranging from low (lowest score in each category; index 5 5), to
 moderate (index 5 6–8), to high (index- 5 9–11). These measures take into
 account only the ecological impact of humans, and do not address local
 ecological variables (such as native plant productivity) that might also
 influence body size and growth. As a proxy for these measures, we
 collected several climatic variables for trapping sites from the WorldClim
 2 database, which has a spatial reso- lution of about 1 km2 (Fick
 & Hijmans, 2017). Climatic variables consid- ered for inclusion in
 our models were (1) annual mean temperature (in degrees Celsius), (2)
 temperature seasonality (measured as the standard deviation of annual mean
 temperature multiplied by 100), (3) the mini- mum temperature of the
 coldest month (in degrees Celsius), (4) the mean temperature of the
 coldest quarter of the year, (5) annual precipi- tation (in mm), and (6)
 precipitation seasonality (measured as thecoefficient of variation of
 monthly precipitation). Climate data were accessed via the R package
 raster v. 2.6-7 (Hijmans & van Etten, 2012), and assigned to
 trapping sites based on latitude and longitude.
description: Along with the ReadMe file (in Excel format), which describes all
 variables in the dataset, there is also an html file with R code used for
 analyses in the publication which will be uploaded to accompany the
 dataset.