Sex differences in the social behavior of juvenile spider monkeys (Ateles geoffroyi)

Previous studies indicate adult spider monkeys (Ateles geoffroyi ) display marked sex differences, including some that may emerge early in life. However, the social behavior of juvenile spider monkeys and potential sex differences has not been adequately studied. Sex differences in the social behavior and proximity patterns of individually recognized juvenile black-handed spider monkeys (A. geoffroyi ornatus) were examined at El Zota Biological Field Station in Costa Rica. Both males and females exhibited sex-typical differences. Only females initiated grooming. Females centered interaction around their mothers and female peers, while males interacted more with adult and juvenile males. Juvenile males were also found in significantly larger parties than females, and were in parties containing adult males significantly more than females. The results of this study indicate that juvenile spider monkeys begin to exhibit sex-typical behaviors at an early age, and that these behavioral patterns prepare them for the social challenges of adulthood

Food selection by the northern yellow-cheeked crested gibbons (Nomascus annamensis), northern Cambodia

Tropical regions have extremely high plant diversity, which in turn supports a high diversity of animals. However, not all plant species are selected by animals as food sources, with some herbivores selecting only specific plants as food as not all plants have the same nutrient make up. Animals must select which food items to include in their diets, as the amount and type of nutrients in their diet can affect lifespan, health, fitness, and reproduction. Gibbon populations have declined significantly in recent years due to habitat destruction and hunting. Northern yellow-cheeked crested gibbon (Nomascus annamensis) is a newly described species, and has a limited distribution restricted to Cambodia, Laos and Vietnam. The northern yellow-cheeked crested gibbons play an important role in seed dispersal, yet little is currently known about this species, including its food selection and nutritional needs. However, data on food selection and nutritional composition of selected food items would greatly inform the conservation of both wild and captive populations of this species. This study aims to quantify food selection by the northern yellow-cheeked crested gibbons by investigating the main plant species consumed and the influence of the availability of food items on their selection. The study also explores the nutritional composition of food items consumed by this gibbon species and identifying key plant species that provide these significant nutrients. A habituated group of the northern yellow-cheeked crested gibbons with five members located in northern Cambodia was studied for 12 weeks during the dry season, and focal animal sampling was used to observe individual feeding behaviours. Four main activity categories were recorded including resting, feeding, travelling and socializing. Phenological data was recorded from transect lines, and plant densities from 20 vegetation plots inside the home range of this group of gibbons were also measured. Seventy-four plant samples from 20 tree and liana species that were consumed by this group of gibbons were collected for nutritional analyses. These samples were initially dried in sunlight, and then oven dried before levels of protein, total non-structural carbohydrates, lipids, fibres and condensed tannins were measured at the Nutritional Ecology Lab at Hunter College of the City University of New York, New York. The northern yellow-cheeked crested gibbon individuals spent most of the time resting, followed by feeding, travelling and socializing. Their main diet was fruit, supplemented with young leaves, flowers, mature leaves, and occasionally insects. Individuals selected food from 37 plant species, but predominately fed on just 16 of these species. The three most-consumed species were fruit from Ilex umbellulata (tree), Ficus. sp (liana), and young leaves from Lithocarpus elegans (tree). There was a significant relationship between feeding time and the availability of flowers, indicating that flowers were actively selected for when present. However, there was no significant relationship between feeding time and the availability of fruit or young leaves. Only a small number of plants bore fruit, with very low densities in the home range of this gibbon study group, but these plants produced a large abundance of fruit. These findings clearly indicate that fruit is the main diet for northern yellow-cheeked crested gibbons in the dry season, with young leaves, flowers, mature leaves and insects acting as secondary food sources. The northern yellow-cheeked crested gibbons selected only a small number of specific plants in their territory for food sources, indicating that any selective logging targeting these plant species would reduce food availability, and restrict the diet of these animals. Fruits consumed by the northern yellow-cheeked crested gibbons were rich in carbohydrates and lipids, while young leaves were richest concentration of protein. Mature leaves had a high moisture content, whereas flowers contained condensed tannins more often than other plant tissues. All plant tissues consumed had similar amount of fibres. Generally, the food items consumed had higher concentrations of carbohydrate than protein or lipids. The overall diet of this group of gibbons was low in lipids. These results indicate that northern yellow-cheeked crested gibbon consumed food items with high concentrations of carbohydrate, and only selected a few food sources with high level of protein. Overall, these findings have contributed important knowledge that can be used for long-term conservation of this gibbon species. There are a small number of key food species in the home range which need special protection. The northern yellow-cheeked crested gibbons consumed food items from different plant species, and as a consequence, all plant species selected play an important role for nutritional requirements by this gibbon species. When considering feeding requirement by the northern yellow-cheeked crested gibbons for captive breeding programs, diets should include fruit, which is rich in carbohydrates, and young leaves, which have high levels of protein

Physiological and ecological implications of rehabilitation and reintroduction of woolly monkeys (Genus lagothrix) in Colombia

Illegal trade and habitat lost are the main issues for primate conservation in many tropical countries. Rehabilitation, and reintroduction programs for captive primates are potential conservation strategies. However, there is a lack of information on how species respond to different captive conditions and translocations. Woolly monkeys (Lagothrix), represent one of the most widely distributed genera in the Neotropics. However, they face many threats and wild populations are decreasing, leading an important number of individuals in captive centers where are usually exposed to incipient conditions and poor diets, associated to high mortality rates. Therefore, to identify tools that contribute to the conservation and the restoration of the ecological functions performed by primates, especially by Colombian woolly monkeys; in this study different approaches were used to identify variables favoring the success of primate's relocations. In the first chapter, I reviewed primate releases worldwide to identify the variables associated to the success the programs. In the second chapter, I evaluated the factors determining the abundance of woolly monkeys, and established a potential criterion of habitat suitability based on the minimum value of fruit productivity necessary to maintain a population of reintroduced primates. The third chapter, was a hormonal approach of the stress response of woolly monkeys during a reintroduction processes. Chapter fourth, evaluated factors determining the initial success of a reintroduction program of woolly monkeys in Colombia. The complementary material included a characterization of the communities of gastrointestinal parasites in captivity and wild, as well as the parasitic change during the reintroduction. Finally, to elucidate ecological effects associated to a potential establishment of the released population, the initial seed dispersal patterns by the reintroduced woolly monkeys is presented.El comercio ilegal y la pérdida de hábitat son los principales problemas para la conservación de primates en muchos países tropicales. Los programas de rehabilitación y reintroducción de primates en cautiverio son posibles estrategias de conservación. Sin embargo, existe una falta de información sobre cómo las especies responden a diferentes condiciones de cautiverio y translocaciones. Los monos churucos (Lagothrix), representan uno de los géneros más ampliamente distribuidos en el Neotrópico. Sin embargo, enfrentan muchas amenazas y las poblaciones silvestres están disminuyendo, lo que lleva a un número importante de individuos a centros de fauna donde suelen estar expuestos a condiciones incipientes y dietas deficientes, asociadas a altas tasas de mortalidad. Por lo tanto, con el fin de identificar herramientas que contribuyan a la conservación y restauración de las funciones ecológicas que realizan los primates, especialmente los monos churucos colombianos; en este estudio se utilizaron diferentes enfoques para identificar las variables que favorecen el éxito de las reubicaciones de primates. En el primer capítulo, revisé las liberaciones de primates en todo el mundo para identificar las variables asociadas al éxito de los programas. En el segundo capítulo, evalué los factores que determinan la abundancia de monos churucos y establecí un criterio potencial de idoneidad del hábitat, basado en el valor mínimo de productividad de fruta necesaria para mantener una población de primates reintroducidos. El tercer capítulo, fue un enfoque hormonal de la respuesta al estrés de estos monos durante un proceso de reintroducción. El capítulo cuarto, evaluó los factores que determinaron el éxito inicial del programa de reintroducción de monos churucos en Colombia. El material complementario incluyó una caracterización de las comunidades de parásitos gastrointestinales de monos en cautiverio y silvestres, así como el cambio parasitario durante la reintroducción. Finalmente,Doctor en Ciencias - BiologíaDoctorad