Mantled howler monkeys research abstract

Ometepe Biological Field Station, San Ramone, Nicaragua


Our research question focused on differences between adult male and female interactions within one meter proximity in mantled howler monkeys (Alouatta palliata). We wanted to find out if there were any statistical differences in the number of interactions taking place between males and females on two trails (Beach and Coffee) on the island of Ometepe, Nicaragua. Our hypotheses were that 1) adult males and females would interact differently within that one meter threshold and 2) there would be differences between interactions taking place between males and females on the Beach and Coffee trails. Our null hypothesis was that there would be no differences between male-female or female-female behaviors or between groups on the Beach and Coffee trails. Our method of research was one-hour opportunistic focal sampling of individuals recording the frequency of their behaviors, dividing the interactions into four categories: male-male, male-female, female-male, and female-female. Within a three-and-a-half week period, we gathered 80 hours of focal samples on both trails (40 hours each), and divided the number of hours evenly between males and females. To calculate any significant difference in interactions between the two trails, we used the Chi-Square test. We found a p-value of 0.645 in the male-female and a p-value of 0.585 in the female-female categories when comparing the Beach to the Coffee trail. As a result we failed to reject our null hypothesis. Important to note is the removal of two categories, the male-male and the female-male which will be addressed further in the discussion.

Peri W. Herman y Christopher W. Weiss