Pehkonen, Eliza (Salt Lake Community College)
Faculty Advisor: Seaboch, Melissa (Salt Lake Community College, Anthropology)
Precipitation-associated behaviors have been observed in several species of primate including bonobos (e.g., building leafy shelters), chimpanzees (e.g., drinking, rain dancing displays), and mantled howler monkeys (e.g., licking rain from the air, altering typical behavior based on weather and season). The purpose of this study is to determine if mantled howler monkeys (Alouatta palliata) exhibit precipitation-associated vocalizations. A. palliata is well known for its vocalizations, which are the loudest sound made by any terrestrial mammal and are used for a wide variety of communicative purposes, such as attracting mates, defending territory, and deterring predation. Given the purpose with which A. palliata vocalizes and the existence of precipitation-associated behaviors within primate species, including A. palliata, it was hypothesized that A. palliata would vocalize in association with climatic events (precipitation and thunder). To test this hypothesis, 41.75 hours of data were collected on A. palliata over a two-week time period during the rainy season at La Selva Biological Station in Costa Rica. All-occurrence sampling was used to record the timing and duration of all A. palliata vocalizations, precipitation, and thunder events. Events were considered accompanied if they occurred within five minutes of one another. Of the 59 observed vocalization events 53% were associated with climatic events. Of the 20 observed precipitation events 90% were accompanied by vocalizations and of the 37 observed thunder events 57% were accompanied by vocalization. Associated vocalizations occurred before, during and after climatic events, however, during or after were most common. The data indicate an association between A. palliata vocalization and precipitation, confirming the hypothesis. Further research is warranted to investigate a possible purpose of precipitation-associated vocalizations, an understanding of which could provide further insight into A. palliata's behavioral interaction with climatic events.