Activity budget, diet, and use of space by two groups of squirrel monkeys (Saimiri sciureus) in eastern Amazonia

Abstract

Squirrel monkeys (Saimiri spp.) are widely distributed in the Amazon basin. This study describes the ecological and behavioral patterns of two social groups of S. sciureus in forests adjacent to the Tucuruí hydroelectric reservoir in eastern Amazonia, including range size, activity budgets, and composition of the diet. The groups were monitored at Base 4 (group B4) and Germoplasma Island (group GI). Quantitative behavioral data were collected using instantaneous scan sampling to record behavior, substrate use, and height. Home ranges were delimited using a GPS to determine group position after each 50 m of movement. Home ranges were 75.0 ha for group B4 (39 members) and 77.5 ha for group GI (32 members). The use of vertical strata was well defined, with a marked preference for the middle and lower levels of the canopy. The activity budgets of both groups were typical of those of other squirrel monkeys and were dominated by foraging (B4 = 48.7 %; GI = 49.6 %), moving (both groups 28.9 %), and feeding (B4 = 14.6 %; GI = 12.4 %). Resting was rare (B4 = 3.5 %; GI = 2.6 %) and less common than social behavior (B4 = 4.3 %; GI = 6.4 %). The diet of both groups was dominated by plant material (B4 = 70.7 % of feeding records; GI = 71.4 %), which is in contrast with the more insectivorous diets recorded for Saimiri at other sites. Group GI spent more time foraging during the dry season, whereas group B4 spent more time in the rainy season when the consumption of fruit increased (significantly, in the case of group GI). The less insectivorous diet of these groups may be due to a number of factors, including the unique habitat configuration at the site and reduced hydrological stress due to the proximity of the reservoir.

The effects of natural substrate discontinuities on the quadrupedal gait kinematics of free‐rangingSaimiri sciureus

“…Squirrel monkeys at TBS are classified as S. sciureus macrodon , one of 10 primate species known to inhabit the site (Marsh, ). Squirrel monkeys were often observed in large groups estimated to be between 30 and 50 individuals, which is consistent with what has been documented for groups living in continuous forests (Pinheiro, Ferrari, & Lopes, ), and for the groups at TBS (Montague, Disotell, & Di Fiore, ). Data on adults and juveniles were collected; no infants were observed.…”

“…Adult squirrel monkeys range in size from 622 to 779 g (Smith & Jungers, ). Squirrel monkeys were used as the model taxon because they are arboreal quadrupeds that utilize the lower to middle forest strata (Fleagle & Mittermeier, ; Fleagle, Mittermeier, & Skopec, ; Marsh, ; Mittermeier & van Roosmalen, ; Pinheiro et al, ), making them an opportune species for filming in the wild. In addition, Saimiri species have been popular model taxa in laboratory gait studies making it ideal for us to compare our results to relevant laboratory results (Miller et al, ; Schmidt, ; Shapiro et al, ; Young, ; Young, ; Vilensky & Patrick, ).…”

Signatures of adaptive evolution in platyrrhine primate genomes

“…Similar signatures can also be found for ancestral Cebinae with "fertilisation" forming the top ranked individual BP GO term, as well as more broadly on motile cilia. In line with the shift to multimale multi-female mating systems, cebid lineages are also characterised by larger group sizes, which is particularly notable for squirrel monkeys (68), and may underlie some of the enriched immune system related results recovered for ancestral Cebidae, squirrel monkeys, and ancestral Cebinae.…”

Female squirrel monkeys as models for research on women’s pelvic floor disorders

“…18 These animals are insectivores and frugivores, and their food includes arthropods, mollusks, small vertebrates, fruits, and seeds. 19 Squirrel monkeys are among the most used neotropical primates in biomedical research, with the first studies reported by Klu¨ver, 20 who provided information on their experimental use and management in captivity. Because of their small size (with a body mass of approximately 1 kg), squirrel monkeys can be kept in smaller spaces than necessary for other model NHPs.…”