Raisa Hernández-Pacheco

Negative density-dependence in female rhesus macaque fertility

contributed by Raisa Hernández-Pacheco
lab instagram: @csulb_quantecolab


Animals, Caribbean, Conservation, Demography, Density-dependence, Dynamics, Ecology, Field, Forest, Fundamental research, Hispanic, Latino/a/x, Life tables, Medicine, Observational, Population ecology, Psychology, Puerto Rican, Restoration, Terrestrial, Woman


View and download in google slides here

Note: click the gear symbol or see below for notes that accompany the presentation

Other Resources

Hernández‐Pacheco, R. et al.  2013. Demographic variability and density‐dependent dynamics of a free‐ranging rhesus macaque population. American Journal of Primatology. https://doi.org/10.1002/ajp.22177 

Hernández-Pacheco, Raisa, and Ulrich K. Steiner. 2017. Drivers of Diversification in Individual Life Courses. The American Naturalist 190(6): E132-E144.

Presentation Notes

Researcher’s Background

Raisa is a population ecologist at California State University-Long Beach, and she studies environmental factors controlling the size of animal populations

PB: Why did you become a biologist?

RHP: It is fun to make research and describe natural phenomena.

PB: What is your favorite part about your job?

RHP: Although we are very busy people, there is an air of freedom that we get to breath every day…

PB: What obstacles have you overcome to get where you are?

RHP: Our job demands a lot of time, thus, having your goals nicely set in your mind helps you to focus and ultimately create a good work-life balance.

PB: What advice do you have for aspiring biologists?

RHP: Not everyone, including family and friends, understand what an academic does for a living. Therefore, to be successful you need to find colleagues that support you on every step of your career. Fortunately, that is not difficult!

PB: Do you feel that any dimension of your identity is invisible or under-represented/marginalized in STEM?

RHP: Yes

PB: Can you elaborate on your answer above?

RHP: I am a Puerto Rican (non-white/hispanic/latino) woman in a highly quantitative field of biology working as a faculty member of a US institution. I am also the only person in my immediate family holding a bachelor’s degree (first generation student under some definitions). Such characteristics are not common among faculty members in US institutions of higher education.

Research Overview

Take home message of study

Density‐dependence is a major mechanism of population regulation. Even when food is not scarce, populations can exhibit density-dependent growth potentially due to social behaviors, and thus it is important to incorporate this information into demographic models for a better understanding of the mechanisms regulating the growth of primate populations.

Study system

Cayo Santiago rhesus macaque social group, Humacao, Puerto Rico. 

Key Research Points

Main figure

Density-dependent relationship between the annual proportion of nonbreeder (NB; closed circles), breeder (B; open circles), and failed breeder (crosses) females and the total number of adult macaques in the population.

Societal Relevance

Cayo Santiago is one of the oldest monkey colonies in the world. This colony provides a unique opportunity to study non-human primates in semi-natural conditions. Given their direct link to humans, research at Cayo Santiago has direct implications to human societies through non-invasive biomedical studies (e.g., autism, disease), behavioral studies (e.g., psychology), ecological studies (e.g., conservation, management), among many others. 

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