Ecologia cognitiva e forrageamento de Alouatta guariba clamitans Cabrera, 1940: os bugios-ruivos possuem mapas mentais?

• Autor(a) principal: Pereira, Thiago da Silva
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional PUCRS
• Texto Completo: http://hdl.handle.net/10923/5415
• topic: ZOOLOGIA; ANIMAIS - HÁBITOS E CONDUTA; NUTRIÇÃO ANIMAL; MACACOS

This study aimed to characterize the foraging patterns of a brown howler monkey group (Alouatta guariba clamitans), evaluating the use of spatial information during resource feeding use in a 5 ha forest fragment located in Barra do Ribeiro, RS, Brazil. The group was composed by 6-7 individuals and was observed over 20 days distributed in three periods between March and October/2007. The behavioral method was used to estimate the time spent in each behavior. All trees visited by the group (n = 654) were identified, measured and mapped. The visibility of the most used trees (n = 26) was estimated and compared with other less frequently used trees (n = 77). The phytosociological survey identified 54 plant species (n = 267) of which 12, described as important feeding sources for howlers, had all their trees mapped and measured (n = 417). Their activity budget was based on resting (57. 6 ± 8. 3%) and feeding (17. 1 ± 5. 2%) and their diet was composed by leaves (53. 3 ± 15. 2%; 35 spp. ), fruits (34. 3 ± 17. 4%, 10 spp. ) and flowers (12. 2 ± 12. 3%; 15 spp. ) (n =38 spp. , 239 trees). The mean day range was 919 ± 256 m in which they used a mean of 81. 6 ± 20. 6 trees and 26. 9 ± 5. 3 species each day. Most of the trees were used for only 1 or 2 days, however 67% of the trees used daily had already been used at a previous sampling day.The group concentrated their activities on large high visibility trees. The greater the visitation percentage within specific tree species, the higher the consumption rate and greater was the selectivity within these species’ trees used for feeding. The closest feeding source of a given species was used in 45% of the feeding bouts, however in 78% of the feeding records there was non-used feeding tree closer than the one used. Besides, the overall route segments were aligned in a specific direction, due, especially, the use fig species. Throughout the study, the group presented foraging strategies that corroborate with our predictions that were made based on evidence gathered that indicate spatial knowledge in frugivorous primates, even with the high degree of folivory observed. They used traveling routes that include high visibility trees as decision nodes. These routes enhanced the monitoring of fruits availability, particularly within fig species. The distance travel was minimized by using closer feeding sources and energetic gain was maximized by using the most productive trees. Although we can’t infer that howler monkeys have mental maps based on this data, they do show that our group used spatial information of the environment to optimize foraging, even during lean periods.