This training program targets those with a strong interest in primatology or wildlife biology. It is based on a long-term study of tamarins at this site. We work with ~5 groups of saddleback and emperor tamarins that are habituated to human observers. Each year, we operate a wildlife handling program that allows us to gain intimate access to the animals for a routine annual health check. This occurs in June and July each year, and during this program we place temporary individual identity tags on each tamarin.
Communication is a primary topic of our research plan for the tamarins at the Los Amigos site. Primates utilize visual, chemical and vocal signals to convey information inter- and intraspecifically, and we currently study two of these signaling methods.
Part 1: Vocal Communication
Vocal communication is the most plastic form of communication: it can express internal and external states, it can affect and be affected by social behavior and environment, and it can be deliberately manipulated by its producer. With respect to tamarins, the function of vocal communication in reproduction, dispersal, and the location of mates — which are integral to the maintenance of stable populations — is not well understood.
Our interests lie in interspecific variation and taxonomic affinities in dispersal and reproductive behavior. Previous research on vocalizations in sympatric S. weddelli and S. imperator has only focused on alarm calling behavior. In order to assess the effects of breeding status, age, and sex on vocal communication we will compile a complete vocal repertoire by recording vocalizations and their social contexts in both S. imperator and S. weddelli. To systematically collect a representative sample of vocal and behavioral data, we will conduct randomized 15-minute focal follows (multiple times) for each individual. During these follows, we will record the vocalizations of the target animal using a digital recorder and a shotgun microphone. Our wildlife handling program involves conducting an annual health check on all animals in our groups, which provides data on the age, sex, and reproductive status of all focal animals for this project. Social behaviors of the target animals, and any behaviors of additional tamarins who respond vocally to an initial call, will also be recorded. Vocal repertoires for each individual will be compiled and analyzed according to several bioacoustic parameters to ascertain markers of individual, age, sex, and reproductive status.
The second component of this research will be playback experiments. Using a speaker and recordings made during follows, we will play vocalizations made by different animals during different behavioral contexts, and record the responses of the group. In this way, we will be able to confirm the meanings of different vocalizations, whether individuals can identify age, sex, and breeding status from vocalizations, and assess whether they are biologically important.
Part 2: Scent Communication
Before we get into the details of this project it helps to highlight some interesting characteristics of tamarins:
- They are miniature
- ~85% of all births are twin births (the next most commonly twinning primates are humans, at ~2% twin births!)
- Groups are structured around a reproductively dominant female who mates with multiple helper males.
- None of the males knows for sure if they parent the twin offspring. Nevertheless, they all stick around and care of the twins until they are independent. This level of male care is rare in the primate world, and only observed in a few species. We call this type of reproductive system cooperative breeding.
- This system of cooperative care would break down if each sexually mature female in a group had her own set of offspring, since the care of twin infants is a demanding and tiring job. Hence, the evolution of female reproductive suppression.
The principle goals of this research is to understand the mechanisms that underlie the behavioral and physiological phenomenon known as reproductive suppression. What forms of communication from dominant female are responsible for suppressing maturation of subordinate females, causing miscarriages, or in some cases convincing them to abandon their young.
Somehow, through a combination of hormones, scent, and sight, dominant females have been found to exert strong suppression on the ovulation of younger females in a group. In captivity, we know that the scent or sight of dominant females delay sexual development of daughters (whereas no such relationship exists between dominant males and their sons). In the wild however, the story can become complicated. Free ranging tamarins live in sprawling territories (relative to a tamarin, anyway) and it rains frequently. Thus, scents do not stick around for very long, and this can lead to subordinate females that are incompletely suppressed. In spite of this, it is extremely rare to find tamarin groups with multiple sets of offspring, so reproductive suppression still occurs; if not by physiological suppression then by other means.
In order to answer this phenomenon in the wild, we spend time with the tamarins and observe them closely. Over the last six years, we have recorded over 2800 hours of information on these intriguing animals and their complex social systems. We combine observational data on scent-marking behavior with assessments of the physiology status of each primate. This includes an examination of their scent glands, collecting data on morphology and development, to determine sexual maturity of both male and female tamarins. We also use fecal samples, collected non-invasively, to monitor changes in sex and stress hormones, especially with regard to female ovulatory cycles. And, we do all of this in the middle of the Amazon rainforest.
Skills and Training
If you join this program, you will get experience in a wide variety of tasks that are applicable to many different fields, including but not limited to primatology. Research assistants who complete this program will be able to:
- Comfortably and safely work and move on and off trail systems
- Conduct half and full-day follows of these miniature primates
- Learn to identify primates based on individual identification markers
- Track primates by movement and vocalizations.
- Become well-versed in scan and focal animal behavior sampling protocols
- Use radio telemetry systems
- Operate high-pitch audio recording systems
- Operate audio analyzing software
- Learn how to collate data collected into a usable database for further analyses
- Record data ad libitum on several unique behaviors such as mating, aggression, competition and grooming
- Identify life-stages of the tamarins, and specific behaviors particular to those time stages
Operate portable audio recording and speaker systems in field conditions
Conduct experimental trials for communication research on a wild population
- Learn to collect non-invasive biological samples and store them while under challenging field conditions
- Process each sample for a variety of uses – genetics, parasite screening, and hormone profiles.
- Learn how to set up a laboratory in the jungle, where things are quite different than your average city laboratory
We are currently recruiting participants with the following requirements. If you are uncertain if you are eligible, contact us to confirm.
- Participants must be at least 18 years of age by the time the training program begins
- Participants must demonstrate a grounding or strong interest in zoology, biology, or anthropology
- Previous field experience is not required
- Participants must justify why this program is important to them, and what they hope to gain from it
- Participants must provide a letter of recommendation from a source that can substantiate the participant’s experience and skills
- Participants must be in good physical condition, with the capability to walk 4 miles a day
- Participants will not be discriminated against for medical conditions they might have, if we determine that being on this project will not pose an immediate risk to their health
- Participants must sign waivers of liability for this project and for the field station before their participation in the project is finalized
- Participants must be willing to maintain long hours in the field, and return to complete data entry in the evenings
- Participants can expect flexible schedules that are dependent on the weather.
- Participants must exhibit a willingness to adjust their schedule to primate daily activity patterns. This can require waking up early, sometimes by 4 or 5 am, and going to bed early, 8 or 9 pm.
Program dates: June 1 – August 10 2018
Start dates: June 1, June 15, June 29
Minimum stay required: 6 weeks
Application deadline: May 1, 2018
Program fee: $2700, $450 each additional week
This project began in 2014, and the primary investigator working on it currently is Efstathia Robakis, a graduate student at Washington University in St. Louis. Her work builds on four additional years of behavioral research on reproductive suppression in callitrichids at Los Amigos. In conjunction with other principal investigators, she will conduct the majority of the behavioral research at the site in 2016 and 2017. This research will contribute to her doctoral thesis.