Endorsed Projects
Identifying the genomic basis of cardiomyopathy in Gorilla gorilla gorilla
Elinor Karlsson (Broad Institute), Eric Baitchman (Zoo New England), Oliver Ryder (San Diego Zoo Global), Linda J. Lowenstine (UC Davis), Ilana Kutinsky (Department of Cardiovascular Medicine, William Beaumont Hospital), Marietta Danforth (Great Ape Heart Project, Zoo Atlanta), Hayley Murphy (Great Ape Heart Project, Zoo Atlanta)
Fibrosing cardiomyopathy is observed in gorillas housed in captivity. Its genomic basis is unknown. We have received funding from The Broad Institute to collect and compare genome-sequence data for gorillas with and without evidence of disease. Our goal is to identify genomic regions associated with disease occurrence. This work is part of a larger effort to develop methods for identifying the genomic basis of health-relevant phenotypes in populations of captive animals. We seek to identify genomic variation associated with fibrosing cardiomyopathy in Gorilla gorilla gorilla, and have received internal funding from Broad Institute to pursue this work. We are writing to request permission to use existing, de-indentified samples (isolated DNA and/or tissues) and associated health data from ~100 individual gorilla with and without fibrosing cardiomyopathy. Below we summarize our planned work and collaboration.
Investigating the Relationship Between Salivary Insulin Levels, Urinary C-peptide, Urinary Adiponectin and Regurgitation and Reingestion in North American Zoo-housed Gorillas
Kaylin Tennant (Cleveland Metroparks Zoo), Elena Less (Cleveland Metroparks Zoo), Mary Ann Raghanti (Kent State University), Kristen Lukas (Cleveland Metroparks Zoo), Pam Dennis (Cleveland Metroparks Zoo)
This study will examine the relationship between salivary insulin levels, urinary c-peptide and adiponectin, and regurgitation and reingestion (R/R) behavior in non-infant (>4 yoa) gorillas. High insulin levels have been shown to inhibit gamma-aminobutyric acid (GABA) receptors in humans (Bansal et al., 2011). As GABA has an active role in inhibiting the relaxation of the lower esophageal sphincter (LES; Lidums et al., 2000; 1999; Beaumont et al., 2008), elevated insulin may increase LES relaxation resulting in reflux and regurgitation (Budiyani et al., 2018). This is supported by the association between insulin resistance and lower esophageal sphincter relaxation in humans (Budiyani et al., 2018). C-peptide is a peptide that is released by the pancreas when insulin is formed and released. It is excreted in the urine and functions as a marker of the amount of insulin produced by the pancreas. Adiponectin is a hormone that regulates blood glucose and fatty acid levels. Low adiponectin is associated with insulin resistance. Given that previous studies have reduced rates of R/R in zoo-housed gorillas by decreasing the amount of simple carbohydrates in their diets (Less et al., 2014; Cabana et al., 2018), we hypothesize that gorillas that exhibit R/R behavior are insulin resistant and thus will have higher fasted salivary insulin levels, higher urinary c-peptide and lower urinary adiponectin than those gorillas that do not exhibit the behavior.
AZA Gorilla Survey: Regurgitation/Reingestion and Diet
Kaylin Tennant (Cleveland Metroparks Zoo), Pam Dennis (Cleveland Metroparks Zoo), Elena Less (Cleveland Metroparks Zoo), Kristen Lukas (Cleveland Metroparks Zoo)
The aim of this study is to determine the current prevalence of regurgitation and reingestion (R/R) and gain an insight on the occurrence of coprophagy in the AZA gorilla population. The study will explore possible associations between the exhibition of these behaviors, with emphasis on R/R, and diet composition. Though various dietary components have been shown to affect R/R in several case studies, this survey will assess the relationship on a larger sale. To do this, an online survey will be sent out to all AZA accredited gorilla institutions. This survey will first collect information on the current prevalence of regurgitation and reingestion (R/R) in the gorilla population. This was last assessed in 1999, at which time approximately 60% of zoo-housed gorillas engaged in the behavior. Having up-to-date data will allow us to measure the current severity of the behavior within the population. In addition, we are requesting the gorilla diets from each zoo, with the weights of each food item (g or lb) outlined. We understand that these diets will likely represent what is fed to the gorillas as a collective group at each insititution, and we will take that into account upon data analysis. Together, these data may provide insight into areas for future studies of the relationship between diets and R/R, and potentially diets and coprophagy, which will hopefully lead to the eventual discovery of more specific variables involved in the elimination of the undesirable behaviors.
Anti-Müllerian Hormone (AMH) as an Indicator of Ovarian Reserve in Gorillas (Gorilla gorilla) in captivity
Anneke Moresco (Denver Zoo), Francis Pau (Oregon National Primate Research Center), Betsy Stringer, DVM (Denver Zoo), Michael Stern (Denver Zoo), and BJ Schoeberl (Denver Zoo)
Gorillas are a carefully managed species in captivity, with specific breeding recommendations each year in order to maintain the genetic diversity. However, implementing such recommendations is a labor and cost intensive process that is not always successful. Part of the lack of success in older females may be due to a low ovarian reserve and declining fertility. In women, such ovarian reserve is measured by assaying serum levels of anti-Müllerian hormone (AMH), a hormone produced by granulosa cells, the cells that surround developing oocytes. The amount of AMH correlates with the number of oocytes that are left in a woman's ovaries. If such a tool were available for gorillas, it would provide very useful information for managers when making decisions about lifetime reproduction of specific individuals as well as evaluating the population as a whole. This study aims to validate the assay to measure AMH in gorillas and to evaluate its usefulness in predicting ovarian reserve in gorillas. We aim to do this by using archived serum samples of adult gorillas known to be cycling, menopausal gorillas known to have stopped cycling and peri-menopausal gorillas known to be cycling irregularly (a feature associated with impending menopause).
Perinatal Mortality in the Gorilla SSP
Pam Dennis (Cleveland Metroparks Zoo), Laura Scoda (The Ohio State University), and Elena Less (Cleveland Metroparks Zoo)
The recent deaths of several captive-born gorilla infants have prompted much discussion on possible causes of infant death in the captive western lowland gorilla (Gorilla gorilla gorilla) population. We wish to conduct a retrospective study examining one possible risk factor associated with pregnancy and neonatal death, i.e., decreased overall infant health due to maternal obesity. We request participation from all zoos that housed female gorillas that conceived or had breeding recommendations at any time during our proposed period of 1995 to present. We request copies of medical records (including any necropsy reports of dam or infant deaths), diet information, and ARKS specimen reports for each female for the time span of six months prior to conception through six months following the birth of the infant. We request the same information for each infant born (first six months post-parturition). In addition, we request a serum sample (if banked serum is available) from each female from within a one-year time period prior to conception. We will measure leptin, adiponectin, insulin, glucose, oxidized LDL, cholesterol, triglycerides, IGF-1, and prolactin. Elena Less uses these same parameters in her study on body condition of SSP gorillas. If an institution has already submitted samples that meet these criteria to Cleveland Metroparks Zoo for use in Elena's study, then we request permission to use the data from Elena's study rather than requesting an additional serum sample.
Understanding the Relationship between Reproductive Lifespan and Longevity in Zoo-housed Female Gorillas (Gorilla gorilla)
Sue Margulis (Canisius College) and Sylvia Atsalis (The San Diego Zoo's Institute for Conservation Research)
Between 2002 and 2009, Drs. Sue Margulis and Sylvia Atsalis conducted a study on reproductive aging in zoo-housed western lowland gorillas (Atsalis et al, 2004; Atsalis and Margulis 2006; Margulis et al., 2007; Atsalis and Margulis, 2008a; Atsalis and Margulis, 2008b). Results from the research demonstrated that gorillas may stop reproducing as early as 38 years of age, or may continue to cycle as late as 52 years of age. Since the completion of the study, many of the females from whom reproductive hormonal analyses were conducted and social and sexual behavioral data were collected have died. Thus, there is a unique opportunity to estimate the median length of post-reproductive lifespan in western lowland gorillas housed in zoos, where longevity conditions may be substantially enhanced compared to the wild. In order to do this, we need additional demographic and pathology records from the SSP and from participating zoos.
Specifically, we aim to address the following questions:
1. What is the post-reproductive lifespan of zoo-housed western lowland gorillas?
For those animals on which we have hormonal data, what was the duration of time between end of reproduction and end of life?
2. What is the lifetime reproductive success for zoo-housed western lowland gorillas?
a. Taking into consideration time during which females were contracepted, what is the fertility and fecundity of females in our study population?
3. Do females show signs of pathology similar to what is found in post-reproductive human females?
a. Ovarian pathology
b. Uterine pathology
c. Osteoporosis
Gorilla Personality and Subjective Well-Being Assessment
Alexander Weiss (University of Edinburgh)
This study's focus is on using gorilla personality as a measure of subjective well-being. The results of this study will be used to compare gorilla personality to that of other great ape species, including humans as well as analyze possible genetic, environmental or maternal influences on development of personality in gorillas.
Ongoing Long-Term Projects
San Diego Frozen Zoo
Ollie Ryder (San Diego Zoo- Conservation Research Center)
The Frozen Zoo®, begun in 1975, is a collection of bioresources including fibroblast cell lines, semen, oocytes, embryos, DNA, blood, and tissue representing about 1,000 mammalian, avian, reptilian and amphibian species/subspecies. Samples are obtained opportunistically from both captive and wild collections throughout the world. The scope of this project is large and covers a wide variety of species of interest in zoo/aquarium collections and affects many conservation interests.
Skin biopsies are processed for tissue culture, cryopreservation, and chromosome analyses to assess reproductive fitness for as many species as feasible. The documented impacts of mutations in managed populations, including dissimilar chromosomal complements or chromosomal heteromorphism, have compromised conservation breeding efforts for numerous species, including those in managed collections. Chromosomal and molecular studies, a crucial component of the Frozen Zoo® efforts, are conducted on an ongoing basis to address this issue, identifying hybrids, sterile individuals, and alerting researchers and curators to risk factors for population viability. Because case studies from the Frozen Zoo® represent the largest bank of comparative chromosomal data for nondomestic vertebrates in the world, this project covers species of interest in captive collections and impacts many conservation interests, including AZA population management initiatives. Information from these studies can also be used to benefit in situ populations. The genetic
analyses that assist in assessing reproductive fitness of animals in managed collections require a continuing effort to obtain samples and establish and freeze tissue cultures.
The Great Ape Heart Project - Detroit Zoological Society
Formally established in 2010, the Great Ape Heart Project (GAHP) addresses a critical need within the zoo community to investigate and understand cardiovascular disease (CVD or heart disease) in great apes. The project was founded with the goal of creating and maintaining a centralized database that can help analyze cardiac data, generate reports, and coordinate cardiac-related research activities, while vastly improving communication among zoos, research facilities and sanctuaries where apes are housed.
See the GAHP website for more information.
Great Ape Neuroscience Project
Bill Hopkins (Emory University), Chet Sherwood (George Washington University), and Mary Ann Raghanti (Kent State University)
The current proposal aims to extend the previous Great Ape Aging Project (GAAP), headed by Dr. Joseph Erwin. The long-term goal of this project is to characterize the neurobiological organization of the brains of all great apes by collecting post-mortem specimens from individuals who had been under the care of North American Zoos. Pragmatically, the aim of the project is to obtain a sufficient number of brains from different age and sex classes of gorillas, chimpanzees, bonobos, and orangutans that will provide statistical power to make strong comparisons among species, and with human specimens in the context of brain aging. Furthermore, although the PIs of this project have their own scientific interest in these brains, the larger goal is to provide a database and specimen bank for making tissue samples and magnetic resonance images of the brains available to the scientific community.
Approved Projects
AZA Bachelor Gorilla Survey Study Proposal
Jodi Carrigan (Zoo Atlanta)
The need for continued study and understanding of bachelor groups in zoos is high. Particularly monitoring of aggression, and its associated risks of wounding and elevated stress, are imperative for bachelor group care and welfare. With this in mind, this project will aim to assemble a comprehensive record of management strategies, facility design, and group history across the entire population of bachelor gorilla groups in AZA accredited institutions. Ultimately, the objectives of this study are to 1) compile a set of best practices for the management of bachelor groups and 2) examine aspects of management strategies, group history, group demographics, and facility design in relation to bachelor group care and welfare.
Retrospective Classification and Management Assessment of Canine Fractures in Captive Managed Populations of Great Apes
Jill Moyse (Houston Zoo), Dr. Kathryn Gamble (Lincoln Park Zoo), Dianne Mohr (Lincoln Park Zoo), George Prevolos (Lincoln Park Zoo)
At this time, it is unknown how many individual great apes in the captive population have broken, fractured and or cracked canine teeth. As several approaches for treatment or repair are possible, it is not known which of these injuries correlate best with the available management options. Long-term effects of no treatment are not predictable. The retrospective project will survey the captive managed great ape population to assess the occurrence of injuries and what treatment was provided to the animal. Zoo veterinarians will be surveyed to document any great apes in their collection that have any incidents of breakage, cracked or fracture of the canine teeth in the last 10 years. We anticipate majority to full participation from the SSP institutions that house great apes and will be able to compile a inventory of all animals that currently have canine fractures, breaks or cracks, the treatment they received and if any common risk factors are associated with the canine fractures. With this information, it is anticipated that prospective guidance of treatment options can be provided to institutions, veterinarians and the great ape SSP when animals present a fracture, break or cracked canine.
Birth Sex Ratio Data and its Importance for the Management of Western Lowland Gorillas In Zoological Settings
Kate Schein (University of Vienna)
Zoological institutions worldwide are faced with the difficulty of housing a surplus of male gorillas. With a total of 856 gorillas living in human care at this time (2010 Studbook) and an almost even split between sexes, a polygynous species, such as the gorilla, poses a managerial challenge. The appropriate management of these individuals however is essential to increasing sustainability in this critically endangered species. In 2000 Faust et al. used a visual modelling program to predict the fate of these charismatic apes living within zoological settings and calculated that within the next 25 years 50 male gorillas will need to be housed in bachelor troops across North America; 12 years later the number of males currently in bachelor troops is almost double that number and this trend is not confined to the US. This study aims to use data on over 1300 individuals born into human care since 1973 to identify possible factors influencing birth sex ratios in Western Lowland Gorillas. The identification of these factors will further the appropriate management of this species and help with breeding recommendations to enhance reproduction.
A Socio-Ecological Comparison of Chimpanzees, Gorillas and Bonobos: Conspecific Proximity, Communication, Feeding Competition, and Implications for Conservation
Scott Milne (Kennesaw State University)
For this project we hypothesize that bonobo and gorilla tolerance of close conspecific proximity during feeding will be higher than the tolerance of chimpanzees, but that gorillas will be more likely to employ gestures as a way to regulate group spacing than bonobos and chimpanzees due to the higher probability of having conspecifics closer by and the decreased need to vocalize to individuals at a distance. Similarly, we would expect bonobos and chimpanzees vocalizing more often than gorillas in the presence of different types of food, suggesting that the absence of gorillas in bonobo habitats may have allowed for them retain vocal communication as well as group cohesiveness, while the presence of gorillas in chimpanzee habitats may have allowed chimpanzees to retain vocal communication but lose relatively cohesive social groups while feeding and allowed gorillas to maintain close social groups with a decreased use of vocal communcation. We predict that we will see these differences emerge as a result of different distributions and qualities of food, a potential reflection of the similarities and differences seen in the wild that are thought to be driven by tendencies of chimpanzees to maintain preferences for high quality ripe fruits in times of scarcity and tendencies of gorillas and bonobos to increase reliance on THV (terrestrial herbaceous vegetation) in times of fruit scarcity. In order to investigate this, we will collect proximity and communicative data on chimpanzees, gorillas, and bonobos housed at the Association of Zoos and Aquariums (AZA) accredited zoos during different feeding scenarios. The following project is proposed to determine if ecological factors play a significant role in the socio-communicative behaviors of gorillas, chimpanzees and bonobos and to determine if similarities can be seen among gorillas and bonobos in an attempt to imply the influence that the presence or absence of species-species competition has on the evolution of social strategies in species that exploit similar resources.
Assessing Stress in Western Lowland Gorillas (Gorilla gorilla gorilla) in Human Care Using Allostatic Load
Ashley Edes (The Ohio State University), Barbara Wolfe, DVM, PhD (The Ohio State University, Columbus Zoo and Aquarium, The Wilds), Douglas Crews, PhD (The Ohio State University)
Lifetime stress substantially contributes to both humans and nonhuman primates (NHP)
developing many chronic degenerative diseases. The allostatic load (AL) model has been successfully used in humans to measure cumulative lifetime stress and predict future health outcomes. AL incorporates numerous biomarkers of stress to determine a composite AL score reflective of current and future health. NHP stress research is typically limited to assessing stress from singular events and using biomarkers in isolation. We propose AL could be used among NHP with the goal of improving health and increasing lifespan. We obtained data from 27 Western lowland gorillas currently or previously housed at the Columbus Zoo and Aquarium. Biomarker values came from medical records and assays of banked serum. Stress events were counted from keeper records. We identified stress events as agonistic interactions with wounding, zoo transfers, and anesthetic events. We developed four exploratory iterations of AL and propose Model 4 AL best predicts stress events and future outcomes in this sample. Using Model 4 AL, sex and historical stress events significantly associate with AL while age closely approaches statistical significance. Using cholesterol, triglycerides, and creatinine as general indicators of health, AL significantly associates with creatinine and triglycerides but not with cholesterol. There is no association between AL and age at death. This research develops a possible path for better understanding long-term consequences of stress on NHP health. Additionally, comparative research on AL in humans and NHP will enhance understanding of similarities, differences, and evolutionary divergences during hominoid evolution.
Using Zoo Gorilla DNA to Create Ebola Virus Vaccines
Michael Jarvis (Oregon Health and Science University)
The long-term goal of this project is to develop a cytomegalovirus (CMV)-based vaccine to interfere with Ebola virus (EBOV) transmission from wild great ape populations to humans. EBOV is highly pathogenic in great apes, with a similar disease course as observed in humans. Substantial 'die-offs' of great apes from EBOV infection are consistently observed in the wild prior to human outbreaks 4-6. Consequently, EBOV is regarded as a major threat to the survival of great apes in the wild. Every mammalian species has it's own highly adapted version of CMV. The immediate aim of the study is to clone gorilla CMV (GoCMV) from Western Lowland gorillas for use as a genetic background for a vaccine. Gorilla fibroblast cells (obtained from Coriell Institute, NJ) will be used as a permissive cell type to isolate and culture GoCMV from gorilla tissue samples.
Kinship and Early History and their Impact on Affiliative Behaviour between Males in Captive Breeder and Bachelor Groups of Western Lowland Gorillas (Gorilla gorilla gorilla)
Kirsten Pullen (Paignton Zoo Environmental Park), Nancy Priston (Oxford Brookes University), and Katie Quantrell (Oxford Brookes University)
This study will investigate social interactions between male western lowland gorillas housed in breeder and bachelor groups to examine the effects that kinship, rearing history and early familiarity have on the affiliative behaviours expressed between individual dyads within these groups. Existing behavioural data (comprising both of affiliative interactions and proximity data) from males in five captive bachelor groups and six captive breeder groups from multiple institutions will be analysed against the data extracted from international studbooks using mixed model ANOVA's. The findings will help to further understanding of the factors influencing the social dynamics of these captive bachelor groups and hopefully aid management decisions of individuals in these groups to enable successful formation of long-term cohesive groups.
Maternal Investment in Captive Western Lowland Gorillas
Tara Stoinski (Zoo Atlanta), Bonnie Perdue (Zoo Atlanta), and Michael Hoff (Dalton College)
We will use the studbook to gather information on infant sex, interbirth intervals (IBI), maternal age, maternal parity, and infant mortality. IBI data will be compared to IBI data from wild western lowland and mountain gorillas to further test the hypothesis that ecological conditions are a primary determinant of maternal investment. Infant sex data will be used to determine if there is a bias in the sex-ratio at birth in captive western lowland gorillas. IBI data will also be used to determine if there is sex biased post-natal investment. Maternal age, parity, IBI, and infant mortality will be used to determine the pattern of investment and reproductive success across the lifespan. We will use the dataset to compare predictions of the various theories related to age, parity, and maternal investment. These data will provide the first quantitative description of western lowland gorilla interbirth intervals, sex ratios, and infant mortality.