Being “Out” in the Field: Who Is Responsible for Health and Safety?


Toward More Equitable and Inclusive Spaces for Primatology and Primate Conservation


Introduction to the Special Section on Equity and Inclusion in Primatology


Including Habitat Country Scientists in all Aspects of Research


Financial Barriers to Primatological Field Work: a Brief Commentary


Examining the Use of Auditory Signals as “Attention-Getters” in Zoo-Housed Gorillas ( Gorilla gorilla gorilla ) and Orangutans ( Pongo pygmaeus and Hybrid)

Abstract

“Attention-getters” are proposed to be gestures that function to attract the attention of a recipient and therefore allow further communication to take place. Their use is an indicator of intentional communication and thus of great interest to researchers in the field of language evolution. However, there is conflicting evidence as to whether nonhuman primates use attention-getters, both in conspecific interactions and in interactions with humans. We examined whether zoo-housed orangutans (Pongo pygmaeus and hybrid [Pongo pygmaeus × Pongo abelii]) and gorillas (Gorilla gorilla gorilla) used auditory signals to initiate visual communication with a human. To test this, a human experimenter stood with food in her hand and her back to the ape. If the ape produced an auditory signal, the experimenter either turned to face the ape or, in the control condition, away from the ape. We found that condition had no significant effect on whether the apes followed their initial auditory signal with a visual signal. Furthermore, the apes did not show greater persistence with, or elaboration of, their auditory signals when the human did not turn to face them, than when she did. In contrast, the apes showed significantly more persistence and elaboration of visual signals when the experimenter turned to face them. Our results suggest that while the orangutans and gorillas were able to discriminate human visual attention and use visual gestures accordingly, they did not attempt to manipulate this attention through the use of auditory behaviors to initiate visual communication.

Habitat Use in a Population of the Northern Muriqui ( Brachyteles hypoxanthus )

Abstract

Habitat loss and fragmentation are known to restrict the movements of primates, including their ability to expand their home ranges. These effects are especially strong at high densities, where home range overlap can result in high rates of agonistic intergroup encounters over range defense. We investigated habitat use and range defense in a population of northern muriquis (Brachyteles hypoxanthus) at the Reserva Particular do Patrimônio Natural – Feliciano Miguel Abdala, in Minas Gerais, Brazil from August 2010 to July 2013. The four groups in this isolated population used 878 ha of forest, with home ranges exhibiting high interannual fidelity in location and low intergroup overlap. Core areas represented 13–29% of the respective home ranges and, except for one group, showed only moderate to low interannual fidelity in successive years. Of 130 intergroup encounters recorded in 2010–2011, significantly more occurred in core areas that overlapped with the range of another group than in areas of home range overlap or areas used exclusively by one group. Daily path lengths of the one group used in assessing range defensibility varied little (1075–1132 m) across years and relative to home range diameter did not meet the criteria for defensibility. However, the occurrence of independent subgroups, combined with a mean monthly detection distance of 242 m, provides strong evidence of range defensibility. These findings point to the importance of fission–fusion dynamics for intergroup range defense, particularly in primates living at high densities in fragmented habitats.

Terrestrial Behavior in Titi Monkeys ( Callicebus , Cheracebus , and Plecturocebus ): Potential Correlates, Patterns, and Differences between Genera

Abstract

For arboreal primates, ground use may increase dispersal opportunities, tolerance to habitat change, access to ground-based resources, and resilience to human disturbances, and so has conservation implications. We collated published and unpublished data from 86 studies across 65 localities to assess titi monkey (Callicebinae) terrestriality. We examined whether the frequency of terrestrial activity correlated with study duration (a proxy for sampling effort), rainfall level (a proxy for food availability seasonality), and forest height (a proxy for vertical niche dimension). Terrestrial activity was recorded frequently for Callicebus and Plecturocebus spp., but rarely for Cheracebus spp. Terrestrial resting, anti-predator behavior, geophagy, and playing frequencies in Callicebus and Plecturocebus spp., but feeding and moving differed. Callicebus spp. often ate or searched for new leaves terrestrially. Plecturocebus spp. descended primarily to ingest terrestrial invertebrates and soil. Study duration correlated positively and rainfall level negatively with terrestrial activity. Though differences in sampling effort and methods limited comparisons and interpretation, overall, titi monkeys commonly engaged in a variety of terrestrial activities. Terrestrial behavior in Callicebus and Plecturocebus capacities may bolster resistance to habitat fragmentation. However, it is uncertain if the low frequency of terrestriality recorded for Cheracebus spp. is a genus-specific trait associated with a more basal phylogenetic position, or because studies of this genus occurred in pristine habitats. Observations of terrestrial behavior increased with increasing sampling effort and decreasing food availability. Overall, we found a high frequency of terrestrial behavior in titi monkeys, unlike that observed in other pitheciids.

Behavior, Diet, and Habitat Use by Blonde Capuchin Monkeys ( Sapajus flavius ) in a Coastal Area Prone to Flooding: Direct Observations and Camera Trapping

Abstract

Coastal areas prone to flooding are relatively neglected in primate studies. Eight out of 29 known populations of Critically Endangered Sapajus flavius occur in areas very close to, or containing, mangrove and várzea (i.e., tidal forests) forests, suggesting that these habitats are important for the species. We monitored Sapajus flavius in a mosaic of mangrove forest, estuarine várzea forest, and terra firme forest (i.e., nonfloodable forest) in northeastern Brazil. We carried out the study through direct observations of the animals, tracking their signs and baited camera trapping, between January and December 2016. Direct observations and signs provided 292 records of Sapajus flavius: 61% in terra firme, 36% in várzea, and 3% in mangrove. We recorded 26 food items consumed: 17 plants and 9 animals. Camera trapping provided 396 records of the animals: 21% in terra firme, 73% in várzea, and 6% in mangrove. Concurrent visits to more than one camera trap station suggested fission–fusion behavior in Sapajus flavius. We recorded carried infants throughout 2016, suggesting the absence of reproductive seasonality in the species. Adult females carried infants on 68% of occasions, suggesting that they play a key role in infant care. Sapajus flavius was largely diurnal but showed some crepuscular activity. Agonistic behaviors, although rare, were positively related to the quantity of food available in the baited camera trap stations, while play behaviors were negatively related to food availability. Coastal areas prone to flood are used by Sapajus flavius, especially várzea, and thus they should receive wide attention from researchers and protection from the government to avoid local extinctions of Sapajus flavius and other primates inhabiting such areas in Brazil.