Rivers create natural variation within landscapes, leading to diverse habitat preferences among primate species. Understanding the habitat preferences of primates can be useful in assessing their overall ecological significance and informing future conservation efforts. The confluence of the Sarapiqui and Puerto Viejo Rivers forms a natural boundary at La Selva Research Station. This area is differentially occupied by primate species like Alouatta palliata (mantled howler monkey), Cebus imitator (white-faced capuchin), and Ateles geoffroyi (Geoffroy's spider monkey). Previous studies on C. imitator have supported a strong preference for secondary forest habitats over riparian habitats due to their lower canopy, as well as the presence of human-planted invasive fruit trees. For this study, I will be investigating the habitat preferences of C. imitatorin relation to the Sarapiqui and Puerto Viejo Rivers, to see if the results are approximate to those of other studies done in northeastern Costa Rica. I hypothesize that there will be a negative correlation between spatial proximity to rivers and C. imitator population density, consistent with the results of prior studies. C. imitator is a monkey of Central and South America, endemic to Honduras through northwestern Ecuador. They are black and white in color, express moderate sexual dimorphism, and weigh from 15 to 40 kg, depending on sex. They are predominantly arboreal, forming multi-male/multi-female groups of up to 24, and have a highly varied omnivorous diet. To test my hypothesis, I will do a census on C. imitator by walking all the trails at La Selva Research Station at a pace of 1 km per hour. I will record the number of individuals and their location by trail name and nearst meter marker. The group's proximity to rivers will be calculated using La Selva Research Station's trail maps, and I will compare the number of sightings near and far from rivers with the results of other research sites.
groups of animals
Since Darwin, biologists have recognized that social animals in nature must balance the need to find food and mates, often competing for both, with the necessity to avoid capture by a predator. Unlike the chronic problem of failing to obtain food and mate, one failure to avoid a predator is catastrophic to future lifetime fitness. We should, therefore, expect that the minute-to-minute behavior of a wild animal reflects these competing selection pressures. Predator avoidance in primates includes freezing, fleeing, vigilance, and alarm calls. Predation on arboreal primates has been described anecdotally in several species. There is little research specifically on predator avoidance in Alouatta palliata, the mantled howler monkey, in Costa Rica. This research will study whether they have predator avoidance behaviors. I hypothesize that A. palliata in La Selva Research Station will exhibit predator avoidance in response to aerial predators. Research will be conducted on a protected reserve with 1,536 hectares of both primary and secondary forest at La Selva Research Station located in Heredia Providence, Costa Rica in May 2022. A. palliata are black, long, and stocky, with brown or yellow saddles on their sides, and can grow to be 22 to 36 inches long and weigh 11 to 15 pounds. A. palliata's predators are harpy eagles (Harpia harpyja) crested eagles (Morpheus guianensis), black hawk eagle (Spizaetus ornatus), jaguar (Panthera onca ocelot), ocelot (Felix pardalis), tayra (Eira barbara), boa constrictor (Boa constrictor), and anaconda (Eunectes marinus). Methods for study will include a 10-minute continuous-focal sampling followed by an instantaneous scan sample. I will record ecological variables such as resting and sleeping site height and the presence of vines at resting and sleeping sites, as well as the number of subjects and their sex, the presence or absence of predators, and behaviors such as vocalization, freezing, vigilance, fleeing, feeding, and resting. I will compare these behaviors in the presence and absence of predators.
Human children have the critical developmental step of socializing partially met through peer-to-peer interactions. Similarly, Ateles geoffroyi (the Central American Spider Monkey) is known to be a social primate where juvenile socialization is critically important for finding food, avoiding predators, preparing for adult life, and handling distinct everyday challenges. A. geoffroyi subadults have a long maturation period (4 to 5 years), and they are more vulnerable to starvation and predation due to their lack of efficiency in foraging and underdeveloped motor skills. The socialization of an A. geoffroyi subadult is crucial to survival, yet limited research on A. geoffroyi subadults suggests socializing interactions mainly display competition for resources and aggressive food-related behavior. There is a lack of further research available about the socialization of A. geoffroyi, other than evidence that they tend to live in social groups with fission-fusion dynamics and often communicate via vocalization. In an attempt to discover how subadult peer-to-peer influence may lead to important socialization skills later in life, I want to investigate how subadult A. geoffroyi interact and socialize with one another. I hypothesize that subadult A. geoffroyi will spend more time socializing with other subadults than with adult A. geoffroyi. This research project will be conducted at La Selva Biological Research Station, located in the north-eastern rainforest of Costa Rica, where A. geoffroyi can be observed in its natural habitat. The method of collecting data will be ten second instantaneous focal sampling. Every ten seconds, I will record individual behaviors of play, allogrooming, embracing, food sharing, aggression, vocalizing, resting, self-grooming, locomoting, eating, drinking, and foraging. These individual behaviors will then be categorized as either solitary, social interaction with an adult, social interaction with another subadult, or social interaction with another species. After data collection is complete, the gathered data will be compared with other published data.
Alloparenting, defined as care provided by individuals other than parents, is a universal behavior among humans that has shaped our evolutionary history and remains important in contemporary society. Human alloparenting takes place in the context of cooperative breeding, wherein individuals live in groups and coordinate their efforts to feed, care for, and protect young to which they themselves did not give birth. Alloparenting has a positive correlation with infant development. Although rare in primates, mantled howler monkeys (Alouatta Palliata) live in social groups where adults engage in alloparenting. Several females can help to look after a single baby, carrying it and grooming it. Young males are often not allowed to alloparent because they can sometimes harm the infants. Mother-infant interactions in A. palliata, such as infant riding, pushing away, sharing food, nursing, and eating on their own, have been observed. In social contexts where mothers interact with physical contact, it provides emotional confidence for both mother and infant, and induces a sense of individual agency. Whether alloparenting occurs in A. Palliata at La Selva Research Station is unknown. This research will investigate alloparenting at this site. I hypothesize that mother A. Palliata will let other group members interact with their infants. This study will take place at La Selva Research Station in May of 2022. La Selva Research Station is in the Caribbean foothills of Costa Rica. It consists of old growth and new growth tropical wet forests. It is home to A. Palliata which are large and stocky with black fur, and most individuals have long, yellow, or brown fur. Adult females typically weigh 4 to 5 kg, and newborn infants weigh 0.4 kg and appear silver to golden brown. The average number of offspring is one, and the average gestation period is 186 days. Data will be collected daily using 1-minute instantaneous scan sampling. I will record the interactions between mother and infant, male and infant, and non-mother female infant, in grooming, carrying, sharing food, and resting, as well as infant solitary behavior. This data will be examined in the presence of alloparenting.
Being the largest New World monkeys, mantled howler monkeys (Alouatta palliata) and spider monkeys (Ateles geoffroyi) vary greatly in terms of appearance, diet, and time budgets. Recent studies show that Alouatta palliata spends about 17% of their time foraging and about 80% of their time in a resting activity. Conversely, Ateles geoffroyi have been shown to budget their time as such: 33.5% foraging, 24.1% resting, 32.6% travelling, and the rest of the time is divided between other categories. This difference in time budgeting is attributed to the difference in diets between species, as Alouatta palliata has a folivorous diet and Ateles geoffroyi has a frugivorous diet. Because fruits are not located in any specific area, but are spread out throughout the forest, there is a general trend of frugivores spending more time looking for food, while folivores spend more time resting to digest food. When comparing similarities between species, simultaneous study of activity budgets between co-existing species is rare. Additionally, activity budgets of Alouatta palliata and Ateles geoffroyi at the La Selva Research Station are unknown. The question then becomes: do these different species attribute their time at the La Selva Research Station similarly? I hypothesize that Alouatta palliata will have more resting and foraging periods compared to Ateles geoffroyi. I will be going to the La Selva Research Station, located in Costa Rica, in May 2022. The La Selva Research Station offers 1,600 hectares of forest where a number of Alouatta palliata and Ateles geoffroyi can be found. Alouatta palliata have fur that ranges from walnut, gold, chocolate brown, and black colors across their bodies; whereas Ateles geoffroyi are reddish brown, yellowish brown, black, or silvery-gray. Weight differences of Alouatta palliata and Ateles geoffroyi are important, too. Alouatta palliata males weigh between 4.5 kg and 9 kg with females weighing 3.1 kg to 7.6 kg. Ateles geoffroyi males, on the other hand, weigh between 7.4 kg and 9 kg, and females weigh between 6 kg and 9.4 kg. Instantaneous focal sampling will be completed at 1-minute intervals. Key characteristics that are going to be observed are feeding, aggression, vocal calling, resting, and travel. This allows a broad enough spectrum that multiple data points are going to be collected for a quantitative analysis. This is completed by comparing the proportion of budget categories observed, by species, relative to the number of scans obtained. These budgeting categories will then be compared to those from other sites.