Research
Behavioral research helps to answer important questions about optimal animal care and well-being, and improves our ability to meet the husbandry, social, and behavioral needs of the animals in our care. By analyzing behavior, researchers try to develop an understanding of animals’ learning processes, motivations, physical abilities, sensory adaptations and social structure. This information is then used to make decisions about managing animals. Working to understand orangutans’ sensory, cognitive, and physiological abilities can also be applied to conservation strategies, thereby benefiting orangutans in the wild as well.
Research using biomaterials is another important aspect, especially when such studies involve passive or voluntary collection of samples (e.g., urine, feces, hair, milk, recently even blood samples or blood pressure readings, etc.), or materials than can be collected opportunistically during scheduled anesthesia (e.g., body measurements taken during routine scheduled physical examination, collection of biological samples from apes not trained for voluntary collection, etc.).
Behavioral research helps to answer important questions about optimal animal care and well-being, and improves our ability to meet the husbandry, social, and behavioral needs of the animals in our care. By analyzing behavior, researchers try to develop an understanding of animals’ learning processes, motivations, physical abilities, sensory adaptations and social structure. This information is then used to make decisions about managing animals. Working to understand orangutans’ sensory, cognitive, and physiological abilities can also be applied to conservation strategies, thereby benefiting orangutans in the wild as well.
Research using biomaterials is another important aspect, especially when such studies involve passive or voluntary collection of samples (e.g., urine, feces, hair, milk, recently even blood samples or blood pressure readings, etc.), or materials than can be collected opportunistically during scheduled anesthesia (e.g., body measurements taken during routine scheduled physical examination, collection of biological samples from apes not trained for voluntary collection, etc.).
The SSP Research/Biomaterials Request Review Process
Research and biomaterials proposals submitted to the Orangutan SSP are reviewed by the SSP's Steering Committee and Advisors. Proposals are judged primarily on their relevance to the Orangutan SSP program. The reviewers' determination will be:
No Objection/Relevant to SSP;
No Objection/Not Relevant to SSP;
or
SSP Objection.
The SSP's determination does not compel individual zoos to participate, nor does it preclude participation. Many zoos require review by their own internal research approval process regardless of the SSP's stance. The SSP's determination is valid for three years from the date of notification, after which continuing proposals must be resubmitted for review.
The SSP's application form intentionally mirrors the Standardized Research Proposal form developed by the AZA's Research and Technology Committee.
Applicants will be notified of the Steering Committee's majority determination within 6 weeks of submission of a complete application.
Click here to download the Orangutan SSP Research Proposal Form.
Click here for Grant Funding information and Application
Why Submit Your Research Proposal to the SSP?
Some studies can be accomplished by collecting data on just a few individuals, and in those cases, researchers may choose to work directly with their local zoo for access to orangutans. Many research projects, however, benefit from the inclusion of data from a large number of individuals. In those cases, working through the Orangutan SSP can be of significant benefit to the scientist because of the broader awareness and encouragement of the SSP. Additionally, for some zoos, SSP review is a prerequisite to acceptance through their own internal research approval process. SSP review can also be beneficial in obtaining outside funding for research projects. Note, however, that the SSP's determination does not compel individual zoos to participate, nor does absence of SSP review preclude participation.
Research and biomaterials proposals submitted to the Orangutan SSP are reviewed by the SSP's Steering Committee and Advisors. Proposals are judged primarily on their relevance to the Orangutan SSP program. The reviewers' determination will be:
No Objection/Relevant to SSP;
No Objection/Not Relevant to SSP;
or
SSP Objection.
The SSP's determination does not compel individual zoos to participate, nor does it preclude participation. Many zoos require review by their own internal research approval process regardless of the SSP's stance. The SSP's determination is valid for three years from the date of notification, after which continuing proposals must be resubmitted for review.
The SSP's application form intentionally mirrors the Standardized Research Proposal form developed by the AZA's Research and Technology Committee.
Applicants will be notified of the Steering Committee's majority determination within 6 weeks of submission of a complete application.
Click here to download the Orangutan SSP Research Proposal Form.
Click here for Grant Funding information and Application
Why Submit Your Research Proposal to the SSP?
Some studies can be accomplished by collecting data on just a few individuals, and in those cases, researchers may choose to work directly with their local zoo for access to orangutans. Many research projects, however, benefit from the inclusion of data from a large number of individuals. In those cases, working through the Orangutan SSP can be of significant benefit to the scientist because of the broader awareness and encouragement of the SSP. Additionally, for some zoos, SSP review is a prerequisite to acceptance through their own internal research approval process. SSP review can also be beneficial in obtaining outside funding for research projects. Note, however, that the SSP's determination does not compel individual zoos to participate, nor does absence of SSP review preclude participation.
Current Projects
Each of the following research projects has been reviewed by the Steering Committee, and SSP-member zoos are encouraged to participate in these studies. Projects are updated on an annual basis for progress and status.
You can find pending results and completed projects here.
The Orangutan SSP supports the Great Ape Heart Project, an IMLS-funded project to design an innovative and coordinated national program to investigate ape cardiovascular disease (CVD) and establish uniform, state of the art cardiac diagnosis, treatment and prevention strategies for great ape CVD.
Non-Invasive Monitoring of Urine Human Chorionic Gonadotropin (hCG) in Pregnant Great Apes George Prevolos, DVM, (Little Rock Zoo), Kathryn C. Gamble, DVM, MS, DACZM, Dipl ECZM (ZHM) (Lincoln Park Zoo). The primary diagnostic technique for diagnosing pregnancy in great apes housed at AZA-accredited zoos is via over-the-counter (OTC) urine human chorionic gonadotropin (hCG) pregnancy tests. In many pregnancies, this technique is also used for monitoring the viability of pregnancy, or pregnancy loss. Anecdotal reports of these tests producing negative results at some point in time during pregnancy, without other evidence of pregnancy loss, has been documented including in female great apes that continue to carry the fetus to term. Although the manufacturers of these OTC pregnancy tests report having >99% accuracy in diagnosing pregnancy in women, the accuracy of these tests are unknown in great apes. Additionally, these tests are utilized solely for initial pregnancy diagnosis rather than long-term monitoring in humans. The lack of data to support the accuracy in diagnosing pregnancy and the anecdotal reports of false-negative results at variable times during a normal pregnancy in this commonly utilized testing method requires further investigation into its efficacy in great apes. This investigation will examine the accuracy of two urine hCG-based OTC pregnancy tests manufactured for human use in diagnosing and continued maintenance of pregnancy in great apes. False-negative results will be further examined for common trends across and between great ape species to better understand the fluctuations in detectable concentrations of hCG in the urine in pregnant great apes. (Ape TAG Endorsed valid until AUG 2026)
Characterization of ovarian aging and reproductive senescence in orangutans (Pongo sp.) in managed care Melissa Fayette, DVM, DACZM (Indianapolis Zoo), Anneke Moresco, MS, DVM, PhD (Reproductive Health Surveillance Program), Dalen Agnew, DVM, DACVP, PhD (Michigan State University, Reproductive Health Surveillance Program). There is currently no conclusive evidence to support or reject the notion that orangutans (Pongo sp.) undergo menopause. Previous research suggests that wild orangutans continue to reproduce throughout their lifespan with no reduction in birth rates associated with age; however, female orangutans in managed care appear to have a prolonged post-reproductive period potentially due to a longer life expectancy. The primary objective of this study is to characterize ovarian reserve and reproductive senescence in orangutans in managed care through histological analysis of archived reproductive tissues to quantify ovarian structures and uterine histomorphology. Another potentially useful measure of ovarian reserve or ovarian pathology in orangutans is serum anti-müllerian hormone (AMH) which is produced by granulosa cells of the developing pre-antral and antral follicles. Pilot data indicates serum concentrations of AMH in some orangutans are higher than any other species in which it has been measured. However, how AMH levels change with age or what normal values are for orangutans is not known. Thus, the second objective is to determine if there is a correlation between serum anti-müllerian hormone (AMH) levels and ovarian AMH expression (assessed through immunohistochemistry) and ovarian reserve in orangutans. Lastly, our study aims to evaluate factors that may influence the timing of menopause in orangutans in managed care such as differences in reproductive life histories, presence of disease, and contraceptive use. From a conservation standpoint, determining whether orangutans undergo menopause and at what age has important repercussions for the reproductive management of this critically endangered species in managed care populations. Data from this study can be utilized to improve recommendations on breeding strategies and may help guide further research to identify possible links between changes in reproductive parameters and vulnerability to health problems associated with menopause such as cardiovascular disease, osteoporosis, and decreased cognitive function. (Reviewed December 2023)
Growth and Development in Captive Juvenile Orangutans Faye Harwell (PhD Candidate at Boston University) & Cheryl Knott, PhD (Boston University & Gunung Palung Orangutan Project). Next to humans, orangutans have the slowest life history amongst primates starting with a long juvenile period. Despite many years of study, little is known about the timing of development in orangutans, the relationship between energetics and growth, the association between sex steroids and developmental events, and the relationship between flanging and skeletal growth. This study will examine growth and development in captive orangutans and fill some of these gaps in our knowledge of this critically endangered great ape. We hope to study the process of flanging for participants that begin flange development during data collection. Methods for this study include collecting urine samples for hormone analyses, taking photographs of the participants’ forearms and facial profiles to estimate growth, and examining historical weight records to assess changes in overall body size. Please contact Faye Harwell or Cheryl Knott with any questions or inquiries about the study. (Renewed July 2022)
Investigating a Genetic Basis for Chronic Respiratory Disease in orangutans The objective of this study is to establish whether there is a genetic cause for orangutan respiratory disease syndrome (ORDS), the chronic lung and sinus disease that decreases the quality of life and increases the rate of death in orangutans. In our previous study, we identified a nonsense mutation (c.484A>T) in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene in heterozygosity in an asymptomatic male and in his sire and offspring. We further demonstrated that the resulting protein from this nonsense mutation was absent when it was introduced in HEK293 cells, and that c.484A>T messenger RNA was severed reduced in nasal epithelial cells from the orangutan, suggesting that this mutation is potentially lethal if combined with another severe CFTR mutation. Finally, we demonstrated the lack of CFTR mutations in an affected male and his affected father. Link to our publication in the American Journal of Primatology is here: https://onlinelibrary.wiley.com/doi/abs/10.1002/ajp.23097 These results suggest that whole genome sequencing could help us better understand if gene abnormalities track with disease. Dr. Taylor-Cousar will carefully review the medical and pedigree records of all orangutans with chronic sinopulmonary disease and those of his/her living and deceased relatives in order to correctly phenotype ORDS-affected and unaffected orangutans. We will collect blood and tissue samples from orangutans at participating zoos for analysis. If it is established that chronic respiratory disease in orangutans is a result of gene abnormalities, this information can be used to guide the use of therapies and breeding decisions in the orangutan population. This research is being led by Dr. Jennifer Taylor-Cousar in collaboration with colleagues at Johns Hopkins University. For questions regarding project participation, please contact Dr. Taylor-Cousar (Renewed April 2022)
Captive Orangutan Dentition Emergence: Felicity Oram is investigating tooth emergence in orangutans. The specific primary objective is to provide a comprehensive updated tooth emergence chart for both species. The need is for more consistent and specific age assignment to better serve husbandry and rehabilitation of orphans and to help build stronger cases for enforcement of existing laws that protect these endangered species in range countries. Additionally, this will provide zoos with a useful updated resource of baseline normals for tooth emergence. Since orangutans are a slow-growing long-lived species of a semi-solitary nature many zoos hold only a few individuals so the benefit of accumulated knowledge in a simple format will be useful for husbandry and veterinary care of zoo residents. Please review the project proposal and the report form for more information; click here for contact information. (Renewed June 2021)
Great Ape Neuroscience Project: The goal of the Great Ape Neuroscience Project is to investigate the neurobiological basis of variation that distinguishes great apes from other primates, defines each great ape species as unique, and helps us to better understand humans’ place in nature. The Great Ape Neuroscience Project originated as an extension of the Great Ape Aging Project (funded by the National Institute on Aging of the National Institutes of Health). The Great Ape Aging Project was conceived of as a means of adding scientific value to elderly apes in captivity. Medical scientists studying the causes of neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases expressed interest in studies of brain and behavior in great apes to determine whether or not the same neurodegenerative processes occurred in them as in afflicted humans. The convergence of these interests and needs led to the development of the Great Ape Aging Project in 1997. This project seeks whole fixed brains from great apes (and other primates) at necropsy. Several documents describe the project and its requirements: Great Ape Neuroscience Project 2011 Progress Report; Project description; TAG project approval letter; Detailed brain collection and submission instructions. Bibliography of articles related to this project. Contact: William Hopkins or Chet Sherwood (Renewed February 2021)
Tannin-Binding Salivary Proteins in Apes: William Aguado (PhD Candidate, Rutgers University), Meredith Bastian (Proceedings of the National Academy of Sciences) Erin Vogel, PhD (Rutgers University & Tuanan Orangutan Research Project). Foraging primates are faced with acquiring adequate nutrition from plants while simultaneously overcoming the challenges posed by plant secondary metabolites (PSMs) – the often toxic, unpalatable, or otherwise harmful chemical compounds that plants produce. PSMs are considered a selective force acting on primate physiology and primates should evolve physiological mechanisms for combatting commonly encountered PSMs. As part of a larger project exploring the relationship between PSMs and the feeding behavior, nutrition, and health of Bornean orangutans (Pongo pygmaeus wurmbii), this research examines whether orangutans have physiological adaptations to a diet rich in tannins – a common class of PSMs known for being toxic and inhibiting digestion. Our goal is to collect saliva from orangutans housed at AZA accredited zoos to see if, and to what extent, orangutans produce tannin-binding salivary proteins as a defense against tannins. We are particularly interested in proline-rich-salivary proteins (PRPs), which are thought to be produced in the saliva of some mammals to bind tannins and decrease their ability to inhibit protein digestion. Once saliva is collected, we will screen for PRPs, measure their abundance in orangutan saliva, and measure their tannin-binding capacity. Knowing the extent to which orangutans produce PRPs will help to explain orangutan diet selection in the wild and increase our understanding of orangutan physiology. (Reviewed December 2020)
Each of the following research projects has been reviewed by the Steering Committee, and SSP-member zoos are encouraged to participate in these studies. Projects are updated on an annual basis for progress and status.
You can find pending results and completed projects here.
The Orangutan SSP supports the Great Ape Heart Project, an IMLS-funded project to design an innovative and coordinated national program to investigate ape cardiovascular disease (CVD) and establish uniform, state of the art cardiac diagnosis, treatment and prevention strategies for great ape CVD.
Non-Invasive Monitoring of Urine Human Chorionic Gonadotropin (hCG) in Pregnant Great Apes George Prevolos, DVM, (Little Rock Zoo), Kathryn C. Gamble, DVM, MS, DACZM, Dipl ECZM (ZHM) (Lincoln Park Zoo). The primary diagnostic technique for diagnosing pregnancy in great apes housed at AZA-accredited zoos is via over-the-counter (OTC) urine human chorionic gonadotropin (hCG) pregnancy tests. In many pregnancies, this technique is also used for monitoring the viability of pregnancy, or pregnancy loss. Anecdotal reports of these tests producing negative results at some point in time during pregnancy, without other evidence of pregnancy loss, has been documented including in female great apes that continue to carry the fetus to term. Although the manufacturers of these OTC pregnancy tests report having >99% accuracy in diagnosing pregnancy in women, the accuracy of these tests are unknown in great apes. Additionally, these tests are utilized solely for initial pregnancy diagnosis rather than long-term monitoring in humans. The lack of data to support the accuracy in diagnosing pregnancy and the anecdotal reports of false-negative results at variable times during a normal pregnancy in this commonly utilized testing method requires further investigation into its efficacy in great apes. This investigation will examine the accuracy of two urine hCG-based OTC pregnancy tests manufactured for human use in diagnosing and continued maintenance of pregnancy in great apes. False-negative results will be further examined for common trends across and between great ape species to better understand the fluctuations in detectable concentrations of hCG in the urine in pregnant great apes. (Ape TAG Endorsed valid until AUG 2026)
Characterization of ovarian aging and reproductive senescence in orangutans (Pongo sp.) in managed care Melissa Fayette, DVM, DACZM (Indianapolis Zoo), Anneke Moresco, MS, DVM, PhD (Reproductive Health Surveillance Program), Dalen Agnew, DVM, DACVP, PhD (Michigan State University, Reproductive Health Surveillance Program). There is currently no conclusive evidence to support or reject the notion that orangutans (Pongo sp.) undergo menopause. Previous research suggests that wild orangutans continue to reproduce throughout their lifespan with no reduction in birth rates associated with age; however, female orangutans in managed care appear to have a prolonged post-reproductive period potentially due to a longer life expectancy. The primary objective of this study is to characterize ovarian reserve and reproductive senescence in orangutans in managed care through histological analysis of archived reproductive tissues to quantify ovarian structures and uterine histomorphology. Another potentially useful measure of ovarian reserve or ovarian pathology in orangutans is serum anti-müllerian hormone (AMH) which is produced by granulosa cells of the developing pre-antral and antral follicles. Pilot data indicates serum concentrations of AMH in some orangutans are higher than any other species in which it has been measured. However, how AMH levels change with age or what normal values are for orangutans is not known. Thus, the second objective is to determine if there is a correlation between serum anti-müllerian hormone (AMH) levels and ovarian AMH expression (assessed through immunohistochemistry) and ovarian reserve in orangutans. Lastly, our study aims to evaluate factors that may influence the timing of menopause in orangutans in managed care such as differences in reproductive life histories, presence of disease, and contraceptive use. From a conservation standpoint, determining whether orangutans undergo menopause and at what age has important repercussions for the reproductive management of this critically endangered species in managed care populations. Data from this study can be utilized to improve recommendations on breeding strategies and may help guide further research to identify possible links between changes in reproductive parameters and vulnerability to health problems associated with menopause such as cardiovascular disease, osteoporosis, and decreased cognitive function. (Reviewed December 2023)
Growth and Development in Captive Juvenile Orangutans Faye Harwell (PhD Candidate at Boston University) & Cheryl Knott, PhD (Boston University & Gunung Palung Orangutan Project). Next to humans, orangutans have the slowest life history amongst primates starting with a long juvenile period. Despite many years of study, little is known about the timing of development in orangutans, the relationship between energetics and growth, the association between sex steroids and developmental events, and the relationship between flanging and skeletal growth. This study will examine growth and development in captive orangutans and fill some of these gaps in our knowledge of this critically endangered great ape. We hope to study the process of flanging for participants that begin flange development during data collection. Methods for this study include collecting urine samples for hormone analyses, taking photographs of the participants’ forearms and facial profiles to estimate growth, and examining historical weight records to assess changes in overall body size. Please contact Faye Harwell or Cheryl Knott with any questions or inquiries about the study. (Renewed July 2022)
Investigating a Genetic Basis for Chronic Respiratory Disease in orangutans The objective of this study is to establish whether there is a genetic cause for orangutan respiratory disease syndrome (ORDS), the chronic lung and sinus disease that decreases the quality of life and increases the rate of death in orangutans. In our previous study, we identified a nonsense mutation (c.484A>T) in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene in heterozygosity in an asymptomatic male and in his sire and offspring. We further demonstrated that the resulting protein from this nonsense mutation was absent when it was introduced in HEK293 cells, and that c.484A>T messenger RNA was severed reduced in nasal epithelial cells from the orangutan, suggesting that this mutation is potentially lethal if combined with another severe CFTR mutation. Finally, we demonstrated the lack of CFTR mutations in an affected male and his affected father. Link to our publication in the American Journal of Primatology is here: https://onlinelibrary.wiley.com/doi/abs/10.1002/ajp.23097 These results suggest that whole genome sequencing could help us better understand if gene abnormalities track with disease. Dr. Taylor-Cousar will carefully review the medical and pedigree records of all orangutans with chronic sinopulmonary disease and those of his/her living and deceased relatives in order to correctly phenotype ORDS-affected and unaffected orangutans. We will collect blood and tissue samples from orangutans at participating zoos for analysis. If it is established that chronic respiratory disease in orangutans is a result of gene abnormalities, this information can be used to guide the use of therapies and breeding decisions in the orangutan population. This research is being led by Dr. Jennifer Taylor-Cousar in collaboration with colleagues at Johns Hopkins University. For questions regarding project participation, please contact Dr. Taylor-Cousar (Renewed April 2022)
Captive Orangutan Dentition Emergence: Felicity Oram is investigating tooth emergence in orangutans. The specific primary objective is to provide a comprehensive updated tooth emergence chart for both species. The need is for more consistent and specific age assignment to better serve husbandry and rehabilitation of orphans and to help build stronger cases for enforcement of existing laws that protect these endangered species in range countries. Additionally, this will provide zoos with a useful updated resource of baseline normals for tooth emergence. Since orangutans are a slow-growing long-lived species of a semi-solitary nature many zoos hold only a few individuals so the benefit of accumulated knowledge in a simple format will be useful for husbandry and veterinary care of zoo residents. Please review the project proposal and the report form for more information; click here for contact information. (Renewed June 2021)
Great Ape Neuroscience Project: The goal of the Great Ape Neuroscience Project is to investigate the neurobiological basis of variation that distinguishes great apes from other primates, defines each great ape species as unique, and helps us to better understand humans’ place in nature. The Great Ape Neuroscience Project originated as an extension of the Great Ape Aging Project (funded by the National Institute on Aging of the National Institutes of Health). The Great Ape Aging Project was conceived of as a means of adding scientific value to elderly apes in captivity. Medical scientists studying the causes of neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases expressed interest in studies of brain and behavior in great apes to determine whether or not the same neurodegenerative processes occurred in them as in afflicted humans. The convergence of these interests and needs led to the development of the Great Ape Aging Project in 1997. This project seeks whole fixed brains from great apes (and other primates) at necropsy. Several documents describe the project and its requirements: Great Ape Neuroscience Project 2011 Progress Report; Project description; TAG project approval letter; Detailed brain collection and submission instructions. Bibliography of articles related to this project. Contact: William Hopkins or Chet Sherwood (Renewed February 2021)
Tannin-Binding Salivary Proteins in Apes: William Aguado (PhD Candidate, Rutgers University), Meredith Bastian (Proceedings of the National Academy of Sciences) Erin Vogel, PhD (Rutgers University & Tuanan Orangutan Research Project). Foraging primates are faced with acquiring adequate nutrition from plants while simultaneously overcoming the challenges posed by plant secondary metabolites (PSMs) – the often toxic, unpalatable, or otherwise harmful chemical compounds that plants produce. PSMs are considered a selective force acting on primate physiology and primates should evolve physiological mechanisms for combatting commonly encountered PSMs. As part of a larger project exploring the relationship between PSMs and the feeding behavior, nutrition, and health of Bornean orangutans (Pongo pygmaeus wurmbii), this research examines whether orangutans have physiological adaptations to a diet rich in tannins – a common class of PSMs known for being toxic and inhibiting digestion. Our goal is to collect saliva from orangutans housed at AZA accredited zoos to see if, and to what extent, orangutans produce tannin-binding salivary proteins as a defense against tannins. We are particularly interested in proline-rich-salivary proteins (PRPs), which are thought to be produced in the saliva of some mammals to bind tannins and decrease their ability to inhibit protein digestion. Once saliva is collected, we will screen for PRPs, measure their abundance in orangutan saliva, and measure their tannin-binding capacity. Knowing the extent to which orangutans produce PRPs will help to explain orangutan diet selection in the wild and increase our understanding of orangutan physiology. (Reviewed December 2020)