Abstract # 7867 Event # 154:

Scheduled for Sunday, August 27, 2017 09:30 AM-09:45 AM: (National Ballroom Salon A) Oral Presentation


TERRESTRIAL ACTIVITY IN TWO SPECIES OF SQUIRREL MONKEYS (SAIMIRI COLLINSI AND SAIMIRI CASSIQUIARENSIS) LIVING IN DISTINCT AMAZONIAN ECOSYSTEMS

A. I. Stone1,2, M. Araujo3 and H. Lima de Queiroz4
1California Lutheran University, Biology Department, Thousand Oaks, CA, USA, 2Graduate Program in Animal Health and Production in Amazonia, Universidade Federal Rural da Amazônia, Belém, Brazil, 3Graduate Program in Zoology, Universidade Federal do Pará and Museu Paraense Emílio Goeldi, Belém, Brazil, 4Instituto de Desenvolvimento Sustentável Mamirauá (IDSM), Tefé, Amazonas, Brazil
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Squirrel monkeys are primarily arboreal quadrupeds, although they have been found to prefer the understory at several study sites. In order to investigate the frequency of terrestriality in Saimiri and the socio-ecological contexts in which it occurs, we analyzed focal, scan and all-occurrence data from two species of squirrel monkeys (S. collinsi and S. cassiquiarensis), inhabiting two different Amazonian ecosystems (high-ground terra firme rainforest and seasonally inundated, várzea rainforest, both in Brazil). In addition to between-site comparisons, we analyzed ground use data according to age of the individuals, season and activity. Results from both species and both sites indicated that squirrel monkeys primarily come to the ground for foraging activities (85.5% of observations), rarely using the ground for crossing open areas. Both adult and juvenile Saimiri collinsi used the ground mostly to procure insect prey, Attalea maripa (Arecaceae) fruit and Strypnodendron pulcherrimum (Leguminosae) fruit, and more so in the dry season. S. cassiquiarensis used the forest floor more frequently than S. collinsi (2.5 events/hour vs. 0.27 events/hour), particularly to forage for arthropods and Caperonia castaneifolia (Euphobriaceae) flowers, and adults were more terrestrial than juveniles (2.06 events/hour and 0.47 events/hour, respectively; Fisher’s exact test; p<0.0001). Although terrestrial behavior in squirrel monkey is not performed without safety costs, it also provides access to an important foraging substrate, especially during periods of low fruit availability.