Gorilla SSP® Research Advisors
are Dr. Nancy Hawkes and Dr. Elena Less. Along with them,
the SSP is supported by several other research scientists
that help guide important scientific-based management principles.
Cleveland Metroparks Zoo
(photo by Susan Griffith)
more about the
Gorilla Health Project.
Zoo New England
(photo by Ellen Slotnick)
does research inform
Read about AZA's
standardized guidelines project.
G.g. gorilla, Utah's Hogle Zoo
(photo by Jameson Weston)
Lincoln Park Zoo
(© Lincoln Park Zoo/Steve Ross)
The science of gorillas
care of animals as complex as gorillas requires a sophisticated
management strategy. Luckily, gorillas are among the most well-studied
animals in the world, and the SSP® benefits from the wide range
of behavioral research being conducted on wild and captive apes.
But even with this vast array of information, there remain many
unanswered questions that can help address issues of animal husbandry
and well-being, as well as the conservation of the species in the
ethogram is a catalog of a species' behavioral repertoire.
The Gorilla Behavior Advisory Group of the Gorilla SSP has
compiled a compilation
of over 45 gorilla ethograms.
cite this document (APA format):
J., Schildkraut, D., Baker, A., Beck, B.B., Bennett, C., duBois,
T. et al. (1991). Compilation of gorilla ethograms.
Atlanta, Georgia: Gorilla Species Survival Plan, Gorilla Behavior
Gorilla Research Overview
Gorillas in captivity provide opportunities both to learn
about the species and to use science to improve the well-being
of its captive members.
See a list of publications
generated from research on gorillas in AZA zoos, 2002-2006.
Studies listed here are taken from AZA's Annual
Report on Conservation and Science.
a Research Proposal to the SSP
Any researcher may submit a proposal to the Gorilla SSP for
endorsement/approval for the following reasons:
encourage AZA institutions housing gorillas to participate
in their research project
2. To obtain a letter of endorsement/approval of their research
project to aid in receiving funding.
3. To gain access to the gorilla studbook.
1. Proposals are sent to the Chair of the Gorilla Species Survival
Plan (Kristen Lukas, Ph.D) or to either of the two research
co-advisors (Nancy Hawkes, Ph.D. and Elena Less, Ph.D.).
2. The chair and research advisors will either request more
information from the principal investigator of the project or
if satisfied with the research proposal, post it to the Gorilla
SSP Management Group and Advisors Listserv.
3. The management group then votes on the classification that
they feel is appropriate for the proposal.
of Voting Classifications for Proposals Submitted to the Gorilla
SSP Management Group:
High priority, good science; we highly encourage zoos to
do whatever they can to accommodate project; furthers goals
of the Gorilla SSP
Moderate priority, good science; institutions should participate
if they can
Low priority, questionable science; not relevant to Gorilla
Mortality in the Gorilla SSP
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
Analysis of Wounding Rates in Gorilla Groups: A Multi-Institutional
Dawn Dodson (Saint Louis Zoo), Kristen Lukas (Cleveland
Metroparks Zoo), and Steve Ross (Lincoln Park Zoo)
Although the research conducted by Kuhar et al. (2008) is
beginning to dispel the myth that bachelor troops are more
volatile than mixed-sex groups, a perception still exists
among zoo managers that it is more dangerous for gorillas
to be housed in all-male groups than mixed-sex groups. There
is some evidence that injuries can be stressful and, at times,
life-threatening for gorillas and veterinary decisions regarding
wound management can have serious consequences for group stability
or individual wellbeing. The Gorilla SSP Veterinary Advisor
Team is currently developing wound management guidelines to
assist zoos in making decisions when wounding events occur.
To gather systematic data on wounding in gorillas, we would
like to apply the same methods employed by Ross et al. (in
press) in documenting and analyzing wounding rates in chimpanzees.
Our goals are to describe the incidence of wounding in the
North American Gorilla SSP population and test the following
null hypotheses for gorillas:
1. Age: There is no difference in the wounding rate of groups
containing males in the young SB range (14-18) and groups
containing older BB males (11-14) or older SB male (18+).
2. Sex: There is no difference in the wounding rate of male
vs. female gorillas.
3. Group: There is no difference in the wounding rate of all-male
vs. mixed-sex gorilla groups.
4. Social unrest: There is no difference in the wounding rate
of stable social groups versus those experiencing social introductions
within one year of the data collection period.
Role of the Microbiome in Great Ape Cardiovascular Disease
J. Christopher Ellis (Duke University), Richard Bergl (North
Carolina Zoo), Kristen Lukas (Cleveland Metroparks Zoo), Elena
Hoellein Less (Cleveland Metroparks Zoo), and Pam Dennis (Cleveland
The objective of this study is to examine how microbial community
composition is altered in gorillas with clinical manifestation
of cardiovascular disease (CVD) compared to baseline gorillas
(no clinical manifestations of CVD or other chronic illnesses
and wild gorillas). We propose examining these three populations
using a series of metagenomic and molecular approaches. To
better understand the role of the gut microbiota in CVD we
will address three specific aims.
1) Determine if the bacterial gut microbiota differ in captive
gorillas suffering from CVD compared to baseline captive gorillas.
2) Determine if the eukaryotic gut microbiota differ in captive
gorillas suffering from CVD compared to baseline captive gorillas.
3) Compare the gut microbiota (both eukaryotic and bacterial)
of captive gorillas and wild gorillas.
Ape Neuroscience Project
Hopkins (Emory University), Chet Sherwood (George Washington
University), and Mary Ann Raghanti (Kent State University)
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.
of Risk Factors Associated with Cardiac Disease in Gorillas
in AZA Institutions
Ilana Kutinsky (Beaumont Hospitals, MI), Suzan Murray (Smithsonian
National Zoological Park), Tom Meehan (Chicago Zoological
Society/ Brookfield Zoo), Hayley Murphy (Zoo New England),
and Pam Dennis (Cleveland Metroparks Zoo)
disease is a major cause of death for gorillas in AZA institutions.
This project seeks to form a comprehensive database incorporating
information from individual gorillas' medical, nutrition and
husbandry records and to also address the diagnostic challenges
associated with identifying heart disease in zoo gorillas.
Hormones, Thyroid Autoantibodies and Thyroid Histology in
Gorillas with Non-Congenital Thyroid Dysfunction
McLachlan (Cedars-Sinai Medical Center)
Limited published information is available for thyroid function
in clinically normal great apes and virtually no data are
available on thyroid autoantibodies. Moreover, there are only
a few reports in the literature on non-congenital thyroid
dysfunction, namely hypothyroidism in a gorilla, a chimpanzee
and two orangutans and hyperthyroidism in one gorilla. Because
of the paucity of available information, the etiology of hypothyroidism
and hyperthyroidism in gorillas is unknown. We have recently
reviewed the information available on thyroid function and
dysfunction in great apes.
To provide "normal ranges" for gorillas, we are
currently testing sera for:-
a) Thyroid hormone levels (thyroxine, tri-iodothyronine, thyrotropin)
b) Thyroid autoantibodies (autoantibodies to thyroglobulin,
thyroid peroxidase and the thyrotropin receptor).
Sera for these studies have been generously made available
by Dr. Hayley Murphey (Zoo Atlanta) and Ryan Devoe (North
Caroline Zoological Park), with approval from their institutions.
Dr. Richard Eberle (Professor of Virology, Department of Veterinary
Pathobiology, Center for Veterinary Health Sciences, Oklahoma
State University) generously transferred to us the "archive"
of primate sera he collected in the late 1980's for his studies
of antibodies to herpes viruses.
In addition to the data we obtain from healthy sera, important
insights may come from testing serum obtained at routine physical
examinations from gorillas with suspected or diagnosed non-congenital
thyroid dysfunction, as well as from thyroid tissue, available
at autopsy, from gorillas with thyroid dysfunction.
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
a. For those animals on which we have hormonal data, what
was the duration of time between end of reproduction and end
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
Diego Frozen Zoo
Ryder (San Diego Zoo- Conservation Research Center)
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
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.
Nutrition, and Health in Captive Western Lowland Gorillas
(Gorilla gorilla gorilla)
Smith (Purdue University), Melissa Remis (Purdue University),
and Ellen Dierenfeld (Novus International)
Graduate student, Bonnie (Katie) Smith, under the supervision
of Dr. Melissa Remis, and with assistance from Dr. Ellen Dierenfeld
(TAG Nutrition Advisor for the Apes), will examine the diet
of gorillas in zoo environments which will contribute to the
formulation of new dietary recommendations to improve the
health and well-being of captive western lowland gorillas.
Although western gorillas in their native habitats forage
actively and consume seasonally variable and complex diets
rich in fiber and polyphenols, captive gorillas ingest high-quality,
low-fiber diets that differ from those likely consumed over
the course of evolution. All accredited U.S. Zoological institutions
that currently house gorillas will be invited to participate
in providing a current diet sheet, followed by a broader questionnaire
based survey directed to document any items not included in
the initially provided diet sheet (including quantities, enrichments,
browse, supplements and seasonality) and the prevalence of
atypical behaviors including R/R.
Personality and Subjective Well-Being Assessment
Alexander Weiss (University of Edinburgh)
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.
the Role of Nuclear Translocations of Mitochondrial DNA as
Genetic Markers in Great Apes
Nicola Anthony (University of New Orleans) and Michael
Jensen-Seaman (Duquesne University)
This study aims to examine genomic sequence databases
of African apes to search for translocations in mitochondrial
DNA, to understand the mechanisms of these gene translocations,
and to evaluate their usefulness as genetic markers. This
study may provide information about the geographical origins
of captive gorillas informing breeding recommendations.
Update: The first specific aim of our study focuses on
the retrieval of nuclear copies of mitochondrial DNA (Numts)
encompassing the control region (CR) of humans, chimpanzees
and gorillas. To do this, we are using BLAST surveys of pubic
human and chimpanzee genome databases and CR screens of an
existing gorilla BAC library and nuclear DNA enriched genomic
libraries prepared from sperm heads isolated from multiple
individuals. With respect to the latter, we have obtained
sperm samples from the Henry Doorly Zoo in Omaha and the Audubon
Center for Research of Endangered Species (ACRES) in New Orleans.
However, DNA concentrations have proved insufficient for us
to build a library with existing resources so we have applied
to the Coriell Institute for Medical Research for access to
gorilla cell lines which we intend to use as a source of genomic
DNA for library construction. The second specific aim of our
work focuses on characterization of nuclear sequences flanking
Numt loci obtained from the first specific aim to assess whether
Numts integrate randomly within the genome or are preferentially
associated with either transposable elements (TEs) or other
sequence motifs. To date, we have found that Numt insertion
events do not appear to be associated with TE but instead
appear to have been facilitated by micro-homologies between
the mitochondrial fragment and nuclear point of insertion.
Our third and final aim focuses on building a panel of gorilla
samples from the US Zoo network in order to (i) assess the
utility of gorilla-specific Numts as population genetic markers
for reconstructing gorilla evolutionary history (ii) identify
the likely geographic origin of gorillas in captivity based
on our extensive work on mitochondrial variation in free-ranging
populations. We have assembled a database of all known matrilines
within the U.S. Zoo network and begun to request samples from
institutions where these animals are held. To date, Audubon
Zoo in New Orleans has donated blood samples from their 3
gorillas. However, we would greatly appreciate additional
samples of gorilla blood, faeces or shed hair from other zoos
and foresee continued work in this last phase of the project
for the next year or so.
pedigree analysis and heart disease
Euan Ashley (Stanford University), Linda Lowenstine (University
of California- Davis), and Ollie Ryder (Center for
Reproduction of Endangered Species, San Diego Zoo)
We are requesting permission from the TAG and SSP coordinators
and studbook keeper to utilize information in the studbook
to map gorilla pedigrees. To identify gorillas with heart
disease we will use the SSP pathology databases compiled by
Dr. Linda Lowenstine, School of Veterinary Medicine, University
of California Davis (Ape TAG, gorilla, orangutan and bonobo
SSP pathology advisor) and Dr. Tom Meehan, Brookfield Zoo
(a Gorilla SSP veterinary advisor) to identify gorillas that
have died of heart disease. Gorillas currently on treatment
for heart disease (database compiled by gorilla SSP veterinary
advisors Drs. Pam Dennis and Hayley Murphy) will also be included.
The pedigree analysis will be conducted through Dr. Euan Ashley,
Stanford University, Department of Medicine, and Stanford
Center for Inherited Cardiovascular Disease.
Metabolism, Primate Evolution and Paleogenetics
Matthew Carrigan (Foundation for Applied Molecular Evolution)
and Steven Benner (Foundation for Applied Molecular Evolution)
dehydrogenase (ADH) and aldehyde dehydrogenase (AlDH) are
two enzymes important in the detoxification of alcohols, including
ethanol. We are a non-profit research foundation that has
recently been funded by National Institute on Alcohol Abuse
and Alcoholism (NIAAA) and the National Institute of Environmental
Health Sciences (NIEHS), both part of the National Institutes
of Health (NIH), to study the evolution of these proteins
within the primate lineage. Ethanol was not always present
in the environment, and it is therefore expected that evolutionary
adaptation has occurred within these lineages since its introduction.
We currently have the sequences of the ADH and AlDH genes
for humans, Pan troglodytes, and Macaca mulatta
(along with partial sequences for Pongo pygmaeus, Gorilla
gorilla, and Papio hamadryas) through the NCBI
genome database. We wish to expand upon the public database
by sequencing the genes from as many other primates as possible,
and to these ends, we seek the help of the larger zoo community.
The exact species of the primates we use in our study is of
less importance than obtaining genetic information from a
wide diversity of primates, including representatives from
each of the major evolutionary branches.
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.
and Early History and their Impact on Affiliative Behaviour
between Males in Captive Breeder and Bachelor Groups of Western
Lowland Gorillas (Gorilla gorilla gorilla)
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.
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.
Linda Vigilant (Max Planck Institute for Evolutionary Anthropology)
and Richard Bergl (North Carolina Zoological Park)
The specific aim of the project is to generate large amounts
(> 50kb) of nuclear sequence data from western and eastern
gorillas in order to improve the estimate of how long ago
the two taxa diverged from one another, and estimate the amount,
direction and duration of gene flow among these different
populations. This project will also illuminate the extent
to which the one-male mating system of gorillas has altered
relative levels of genetic variation on the Y-chromosome,
X-chromosome and autosomes relative to the levels found in
chimpanzees and humans.
GORILLA SSP RESEARCH PROJECTS
of Primate Chow from Gorilla Diets: The Impact on Behavior,
Adiposity and Health
Elena Hoellein Less (Cleveland Metroparks Zoo), Richard
Bergl (North Carolina Zoo), Shana Lavin (Lincoln Park Zoo),
Pam Dennis (Cleveland Metroparks Zoo), Sylvia Atsalis (CRES,
The Zoological Society of San Diego), Kristen Lukas (Cleveland
Metroparks Zoo), and Christopher Kuhar (Cleveland Metroparks
The proposed study examines the influence of typical captive
diets on gorilla behavior, obesity and overall health. In
particular, we propose that for captive western lowland gorillas,
replacing chow and fruit with larger quantities of plant material
will reduce undesirable behaviors, increase activity and reduce
adiposity. To test this hypothesis, we will: measure the amount
of time engaged in physical activity (i.e. foraging, climbing,
running, etc...) and the rate of feeding-related undesirable
behaviors according to the two different diet types; determine
concentrations of serum hormones related to adiposity and
biological markers of inflammation; examine stool volatile
fatty acids; and apply body measurement indices of physical
condition in a sample of captive western lowland gorillas.
Update: The authors are preparing this study for publication,
and more results will be available soon.
Adiposity in Captive Gorillas: Variance in BMI, Diet, and
Elena Hoellein Less (Cleveland Metroparks Zoo), Pam Dennis
(Cleveland Metroparks Zoo), Kristen Lukas (Cleveland Metroparks
Zoo), Christopher Kuhar (Cleveland Metroparks Zoo), and Mary
Ann Raghanti (Kent State University)
The proposed study examines the influence of diet and activity
level on gorilla adiposity. In particular, we propose that
for captive western lowland gorillas, those gorillas that
are fed a diet more similar to their wild counterparts and/or
spend a large percentage of time active will have lower adiposity
as reflected by body mass index and hormone levels. To test
these hypotheses, we propose to survey the diet composition
and feeding protocol along with activity levels in all gorillas
housed in Association of Zoo and Aquarium institutions. In
conjunction with assessing diet and activity we will measure
(1) serum hormone concentrations related to adiposity, (2)
biological markers of inflammation and (3) body measurement
The authors are preparing this study for publication, and
more results will be available soon.
Longitudinal Assessment of Gorilla Personality
Tara Stoinski (Zoo Atlanta), Bonnie Perdue (Zoo Atlanta),
Chris Kuhar (Cleveland Metroparks Zoo), Kristen Lukas (Cleveland
Metroparks Zoo), and Ken Gold (American Humane Association)
The Gorilla Behavior Index (GBI) is a measure of gorilla personality
(Gold, 1993). Seven years later in 2000, Kuhar et al. (2006)
replicated these dimensions in a sample of 119 male gorillas.
A subset of 79 individuals was sampled at both time points,
and we recently analyzed the stability of personality across
time in those individuals (Perdue et al., 2009). Although
this was the first analysis to examine stability in personality
traits in apes, it had two limitations. First, it only looked
for stability over a relatively short portion of a gorilla's
lifespan (7 years). Thus, data are still needed to examine
stability across the lifespan, and, in particular, from subadult
to adulthood. Gathering personality data again now permits
an analysis over a 16 year period (1993-2009), thus ensuring
that all individuals assessed as infants or juveniles in 1993
are now fully adult. Second, the analysis only included males
as the 2000 personality data were only collected on males.
Since the original dataset included females, we would now
like to also gather data on females to look for sex differences
in personality stability.
Update: Data analysis is ongoing and results will be available
Sanctuary Alliance (PASA) Ape Modeling Project
Lisa Faust (Lincoln Park Zoo) and Ben Beck (Great Ape Trust)
project's focus is on modeling the demography of representative
great ape sanctuary populations using the captive population
studbook to project the amount of space needed to house existing
sanctuary specimens and accommodate new specimens being confiscated.
The model should provide a valuable example of the time and
resources required to maintain confiscated ape populations
throughout their natural lifespan, giving sanctuaries a better
understanding of the nature and extent of their commitment.
Reports on gorilla dynamics were sent directly to sanctuary
managers. Because more PASA sanctuaries contain chimpanzees,
work on only chimpanzees was published:
Faust, LJ., Cress, D., Farmer, KH., Ross, SR., and Beck, BB.
2011. Predicting capacity demand on sanctuaries for African
chimpanzees (Pan troglodytes). International Journal
of Primatology: Published online 8 Mar 2011.
Blood Types for SSP Populations of Great Apes
Kathryn Gamble (Lincoln Park Zoo) and Jill Moyse (Lincoln
humans and domestic mammals, blood typing plays an important
in providing excellent medical care in critical care situations.
It has been repeatedly demonstrated in the literature that
humans and great apes have conserved identities within the
standard blood typing categories of A-B-O and D(Rh factor).
Development of simple table-top laboratories techniques to
identify these most basic of blood groups in human patients
may be applied to similar benefit in the great ape species.
This study is complete and authors are currently preparing
the study for publication. When available, we will post a
summary of results.
Great Apes and Their Interactions with Local Wildlife
Steve Ross (Lincoln Park Zoo) and Elizabeth Lonsdorf (Lincoln
Although there are published reports of wild chimpanzees,
bonobos, and orangutans hunting and consuming vertebrate prey,
data pertaining to captive apes remain sparse. In this survey-based
study, we evaluate the prevalence and nature of interactions
between captive great apes and various indigenous wildlife
species that range into their enclosures in North America.
Our hypotheses were threefold: (a) facilities housing chimpanzees
will report the most frequent and most aggressive interactions
with local wildlife; (b) facilities housing orangutans and
bonobos will report intermediate frequencies of these interactions
with low levels of aggression and killing; and (c) facilities
housing gorillas will report the lowest frequency of interactions
and no reports of killing local wildlife. Chimpanzees and
bonobos demonstrated the most aggressive behavior toward wildlife,
which matched our predictions for chimpanzees, but not bonobos.
This fits well with expectations for chimpanzees based on
their natural history of hunting and consuming prey in wild
settings, and also supports new field data on bonobos. Captive
gorillas and orangutans were reported to be much less likely
to chase, catch and kill wildlife than chimpanzees and bonobos.
Gorillas were the least likely to engage in aggressive interactions
with local wildlife, matching our predictions based on natural
history. However unlike wild gorillas, captive gorillas were
reported to kill (and in one case, eat) local wildlife. These
results suggest that some behavioral patterns seen in captive
groups of apes may be useful for modeling corresponding activities
in the wild that may not be as easily observed and quantified.
Furthermore, the data highlight the potential for disease
transmission in some captive settings, and we outline the
associated implications for ape health and safety.
The authors wish to thank all zoos which participated in this
study. The full results are published in:
Ross SR, Holmes AN, Lonsdorf EV. 2009. Interactions Between
Zoo-Housed Great Apes and Local Wildlife. American Journal
of Primatology 71(6):458-465.
the Prevalence and Characteristics of Hair Plucking Behavior
in Captive Western Lowland Gorillas (Gorilla gorilla gorilla)
Elena Less (Cleveland Metroparks Zoo) and Kristen Lukas
(Cleveland Metroparks Zoo)
This study's focus is on describing hair plucking behavior
in captive gorillas, as well as evaluating risk factors that
may predispose gorillas to exhibit this behavior. The results
will be used to inform captive management decisions on ameliorating
this behavior in the captive population.
This survey is complete and data is currently being analyzed
by the PI. The authors wish to thank the 38 zoos who participated.
of SIVgor Infection in Captive Gorillas
Brandon Keele (University of Alabama) and Beatrice Hahn
(University of Alabama)
There was recently reported in Nature evidence
of a naturally occurring simian immunodeficiency virus infection
in wild gorillas (G. g. gorilla) which was designated
as SIVgor. The objective of this study is to determine if
any captive gorillas are likewise infected. This study requests
either plasma or fecal samples for each captive gorilla.
No captive gorillas tested positive for SIVgor infection.
Reproduction Using Sex-Sorted Sperm: A Management Strategy
for Captive Gorillas
Naida Loskutoff (Henry Doorly Zoo)
In light of the precarious state of gorillas in their natural
habitats, the American Zoo and Aquarium Association (AZA)
Gorilla Species Survival Plan (SSP) proposes the application
of assisted reproductive technology as a means for allowing
the genetic contributions of these animals to increase the
likelihood of long-term genetic health and survival of the
species. The aim of this research is to use the most recent
advances in human assisted reproductive technologies as a
model to develop methodology for producing female offspring
from genetically underrepresented individuals in the Gorilla
SSP. This study requests sperm samples from male gorillas
and oocytes for female gorillas.
Update: We adapted flow cytometry technology for high-purity
sorting of X chromosome-bearing spermatozoa in the western
lowland gorilla (Gorilla gorilla gorilla). Our objectives
were to develop methodologies for liquid storage of semen
prior to sorting, sorting of liquid-stored and frozen-thawed
spermatozoa, and assessment of sorting accuracy. In study
1, the in vitro sperm characteristics of gorilla ejaculates
from one male were unchanged (P>0.05) after 8 hr of liquid
storage at 15°C in a non-egg yolk diluent (HEPES-buffered
modified Tyrode's medium). In study 2, we examined the efficacy
of sorting fresh and frozen-thawed spermatozoa using human
spermatozoa as a model for gorilla spermatozoa. Ejaculates
from one male were split into fresh and frozen aliquots. X-enriched
samples derived from both fresh and frozen-thawed human semen
were of high purity, as determined by fluorescence in situ
hybridization (FISH; 90.7%±2.3%, overall), and contained
a high proportion of morphologically normal spermatozoa (86.0%±1.0%,
overall). In study 3, we processed liquid-stored semen from
two gorillas for sorting using a modification of methods for
human spermatozoa. The sort rate for enrichment of X-bearing
spermatozoa was 7.3±2.5 spermatozoa per second. The
X-enriched samples were of high purity (single-sperm PCR:
83.7%) and normal morphology (79.0%±3.9%). In study
4 we examined frozen-thawed gorilla semen, and the sort rate
(8.3±2.9 X-bearing sperm/sec), purity (89.7%), and
normal morphology (81.4%±3.4%) were comparable to those
of liquid-stored semen. Depending on the male and the type
of sample used (fresh or frozen-thawed), 0.8-2.2% of gorilla
spermatozoa in the processed ejaculate were present in the
X-enriched sample. These results demonstrate that fresh or
frozen-thawed gorilla spermatozoa can be flow cytometrically
sorted into samples enriched for X-bearing spermatozoa.
O'Brien, JK., Losuktoff, NM., et al. 2005. Flow cytometric
sorting of fresh and frozen-thawed spermatozoa in the western
lowland gorilla (Gorilla gorilla gorilla). American
Journal of Primatology 66 (4): 297-315.