Tara S Stoinski
Biographic Data
| ID | 3072790 |
|---|---|
| NAME | Tara S Stoinski |
| GIVEN NAMES | Tara S |
| FAMILY NAME | Stoinski |
| SIGNATURE | STOINSKI T S |
| AFFILIATIONS | Zoo Atlanta |
| ORCID | 0000-0002-8287-1621 |
| VERIFIED | Yes |
| TOTAL WORKS | 42 |
| TOTAL CITATIONS | 96 |
| AUTHOR COUNT | 42 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2001 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 6 |
Behavioural and spatial flexibility in mountain gorillas (Gorilla beringei beringei) in response to intergroup encounters
Intergroup encounters are a powerful selective force shaping behaviour. Primates can adjust ranging, activity, and affiliation patterns to mitigate the costs associated with intergroup conflict or enhance intragroup cohesion to facilitate collective action. However, empirical evidence for these adaptive responses remains equivocal. We investigated how intergroup encounters influence the behaviour of mountain gorillas ( Gorilla beringei beringei )…
Urinary oxytocin and cortisol concentrations vary by group type in male western lowland gorillas (Gorilla gorilla gorilla) in North American zoos
A partnership to build scientific capacity of Rwanda's future conservationists: The Memoirs Program
The future of primates depends on conservationists in primate range countries having the education and opportunities needed to facilitate conservation efforts. However, most primates are found in countries where conservation is underfunded. Rwanda is home to 14 primate species, with three being listed as endangered on the International Union for Conservation of Nature (IUCN) Red List. Their remaining native habitats are scarce, highly fragmented,…
Group structure, but not dominance rank, predicts fecal androgen metabolite concentrations of wild male mountain gorillas ( Gorilla beringei beringei )
Androgens are important mediators of male‐male competition in many primate species. Male gorillas' morphology is consistent with a reproductive strategy that relies heavily on androgen‐dependent traits (e.g., extreme size and muscle mass). Despite possessing characteristics typical of species with an exclusively single‐male group structure, multimale groups with strong dominance hierarchies are common in mountain gorillas. Theory predicts that an…
Western lowland gorillas ( Gorilla gorilla gorilla ) do not show an aversion to inequity in a token exchange task
Although individuals in some species refuse foods they normally accept if their partner receives a more preferred one, this is not true across all species. The cooperation hypothesis proposes that this species‐level variability evolved because inequity aversion is a mechanism to identify situations in which cooperation is not paying off, and that species regularly observed cooperating should be more likely to be averse to inequity. To rule out ot…
Intragroup Behavioral Changes Following Intergroup Conflict in Mountain Gorillas (Gorilla beringei beringei)
Infant handling by female mountain gorillas: Establishing its frequency, function, and (ir)relevance for life history evolution
OBJECTIVES: Infant handling describes cases in which youngsters are temporarily removed from the care of their mothers and "taken care of" (held, carried, etc.) by other conspecifics. Handlers may gain indirect fitness benefits from these actions and can practice mothering skills, thereby improving the odds of survival of their own infants. Great apes are notable for displaying little infant handling. Apart from anecdotal observations, no publish…
Faster growth corresponds with shallower linear hypoplastic defects in great ape canines
Validating the use of a commercial enzyme immunoassay to measure oxytocin in unextracted urine and saliva of the western lowland gorilla (Gorilla gorilla gorilla)
Retracted Article: Biologically validating the measurement of oxytocin in western lowland gorilla (Gorilla gorilla gorilla) urine and saliva using a commercial enzyme immunoassay
Unexpected terrestrial hand posture diversity in wild mountain gorillas
OBJECTIVES: Gorillas, along with chimpanzees and bonobos, are ubiquitously described as 'knuckle-walkers.' Consequently, knuckle-walking (KW) has been featured pre-eminently in hypotheses of the pre-bipedal locomotor behavior of hominins and in the evolution of locomotor behavior in apes. However, anecdotal and behavioral accounts suggest that mountain gorillas may utilize a more complex repertoire of hand postures, which could alter current inte…
Quantifying linear enamel hypoplasia in Virunga Mountain gorillas and other great apes
OBJECTIVE: Linear enamel hypoplasia (LEH) is a condition marked by localized reductions in enamel thickness, resulting from growth disruptions during dental development. We use quantitative criteria to characterize the depth of LEH defects and "normal" perikymata in great apes. We test the hypothesis that mountain gorillas have shallow defects compared to other taxa, which may have led to their underestimation in previous studies. MATERIALS AND M…
Incisor tooth wear and age determination in mountain gorillas from Volcanoes National Park, Rwanda
OBJECTIVES: Ecological factors, but also tooth-to-tooth contact over time, have a dramatic effect on tooth wear in primates. The aim of this study is to test whether incisor tooth wear changes predictably with age and can thus be used as an age estimation method in a wild population of mountain gorillas (Gorilla beringei beringei) from Volcanoes National Park, Rwanda. MATERIALS AND METHODS: ) as a proxy for incisal macrowear. Linear and quadratic…
Toughness of the Virunga mountain gorilla ( Gorilla beringei beringei ) diet across an altitudinal gradient
The robust masticatory system of mountain gorillas is thought to have evolved for the comminution of tough vegetation, yet, compared to other primates, the toughness of the mountain gorilla diet is unremarkable. This may be a result of low plant toughness in the mountain gorilla environment or of mountain gorillas feeding selectively on low-toughness foods. The goal of this paper is to determine how the toughness of the mountain gorilla diet vari…
A radiographic study of permanent molar development in wild Virunga mountain gorillas of known chronological age from R wanda
OBJECTIVES: While dental development is important to life history investigations, data from wild known-aged great apes are scarce. We report on the first radiographic examination of dental development in wild Virunga mountain gorillas, using known-age skeletal samples recovered in Rwanda. MATERIALS AND METHODS: In 43 individuals (0.0-14.94 years), we collected radiographs of mandibular molars, and where possible, cone beam CT scans. Molar crown a…
Body growth and life history in wild mountain gorillas ( Gorilla beringei beringei ) from Volcanoes National Park, Rwanda
OBJECTIVES: Great apes show considerable diversity in socioecology and life history, but knowledge of their physical growth in natural settings is scarce. We characterized linear body size growth in wild mountain gorillas from Volcanoes National Park, Rwanda, a population distinguished by its extreme folivory and accelerated life histories. METHODS: In 131 individuals (0.09-35.26 years), we used non-invasive parallel laser photogrammetry to measu…
Group structure predicts variation in proximity relationships between male–female and male–infant pairs of mountain gorillas (Gorilla beringei beringei)
Validation of two independent photogrammetric techniques for determining body measurements of gorillas
The ability to accurately measure morphological characteristics of wild primates in the field is challenging, yet critical for understanding fundamental aspects of their biology and behavior. Recent studies have shown that digital photogrammetry can be used to non‐invasively measure morphological traits of wild primates, as it allows for the determination of geometric properties of objects remotely from photographic images. We report here on a ra…
Age‐related changes in molar topography and shearing crest length in a wild population of mountain Gorillas from Volcanoes National Park, Rwanda
OBJECTIVES: Great ape teeth must remain functional over long lifespans. The molars of the most folivorous apes, the mountain gorillas, must maintain shearing function for 40+ years while the animals consume large quantities of mechanically challenging foods. While other folivorous primates experience dental senescence, which compromises their occlusal surfaces and affects their reproductive success as they age, it is unknown whether dental senesc…
Tooth wear and feeding ecology in mountain gorillas from Volcanoes National Park, Rwanda
OBJECTIVES: Ecological factors have a dramatic effect on tooth wear in primates, although it remains unclear how individual age contributes to functional crown morphology. The aim of this study is to determine how age and individual diet are related to tooth wear in wild mountain gorillas (Gorilla beringei beringei) from Volcanoes National Park, Rwanda. MATERIAL AND METHODS: We calculated the percent of dentine exposure (PDE) for all permanent mo…
Age‐related motor dysfunction: Manual slowing in Gorilla gorilla gorilla
Aging in humans and rhesus monkeys is commonly associated with motor function decrements including dexterity, speed, and strength. Despite their longevity and phylogenetic relatedness to humans, the effects of aging on motor function in non-human apes have been minimally studied. We conducted two experiments with western lowland gorillas (11-54 years of age) to determine whether aged gorillas exhibit motor deficits similar to those seen in other …
Energetic responses to variation in food availability in the two mountain gorilla populations ( Gorilla beringei beringei )
OBJECTIVE: Here, we compare food availability and relate this to differences in energy intake rates, time spent feeding, and daily travel distance of gorillas in the two populations. Comparative intraspecific studies investigating spatiotemporal variation in food availability can help us understand the complex relationships between ecology, behavior, and life history in primates and are relevant to understanding hominin evolution. Differences in …
Brain organization of gorillas reflects species differences in ecology
Gorillas include separate eastern ( Gorilla beringei ) and western ( Gorilla gorilla ) African species that diverged from each other approximately 2 million years ago. Although anatomical, genetic, behavioral, and socioecological differences have been noted among gorilla populations, little is known about variation in their brain structure. This study examines neuroanatomical variation between gorilla species using structural neuroimaging. Postmo…
Double invisible displacement understanding in orangutans: Testing in non-locomotor and locomotor space
Mountain gorilla ranging patterns: Influence of group size and group dynamics
Since the 1980s, the Virunga mountain gorilla population has almost doubled, now reaching 480 individuals living in a 430-km(2) protected area. Analysis of the gorillas' ranging patterns can provide critical information on the extent and possible effects of competition for food and space. We analyzed 12 years of daily ranging data and inter-group encounter data collected on 11 gorilla groups monitored by the Karisoke Research Center in Rwanda. Du…
Body growth and life history in wild mountain gorillas ( Gorilla beringei beringei ) from Volcanoes National Park, Rwanda
OBJECTIVES: Great apes show considerable diversity in socioecology and life history, but knowledge of their physical growth in natural settings is scarce. We characterized linear body size growth in wild mountain gorillas from Volcanoes National Park, Rwanda, a population distinguished by its extreme folivory and accelerated life histories. METHODS: In 131 individuals (0.09-35.26 years), we used non-invasive parallel laser photogrammetry to measu…
Variability in the developmental life history of the genus Gorilla
Life history is influenced by factors both intrinsic (e.g., body and relative brain size) and extrinsic (e.g., diet, environmental instability) to organisms. In this study, we examine the prediction that energetic risk influences the life history of gorillas. Recent comparisons suggest that the more frugivorous western lowland gorilla shows increased infant dependence, and thus a slower life history, than the primarily folivorous mountain gorilla…
Age‐related changes in molar topography and shearing crest length in a wild population of mountain Gorillas from Volcanoes National Park, Rwanda
OBJECTIVES: Great ape teeth must remain functional over long lifespans. The molars of the most folivorous apes, the mountain gorillas, must maintain shearing function for 40+ years while the animals consume large quantities of mechanically challenging foods. While other folivorous primates experience dental senescence, which compromises their occlusal surfaces and affects their reproductive success as they age, it is unknown whether dental senesc…
Energetic responses to variation in food availability in the two mountain gorilla populations ( Gorilla beringei beringei )
OBJECTIVE: Here, we compare food availability and relate this to differences in energy intake rates, time spent feeding, and daily travel distance of gorillas in the two populations. Comparative intraspecific studies investigating spatiotemporal variation in food availability can help us understand the complex relationships between ecology, behavior, and life history in primates and are relevant to understanding hominin evolution. Differences in …
Quantifying linear enamel hypoplasia in Virunga Mountain gorillas and other great apes
OBJECTIVE: Linear enamel hypoplasia (LEH) is a condition marked by localized reductions in enamel thickness, resulting from growth disruptions during dental development. We use quantitative criteria to characterize the depth of LEH defects and "normal" perikymata in great apes. We test the hypothesis that mountain gorillas have shallow defects compared to other taxa, which may have led to their underestimation in previous studies. MATERIALS AND M…
Tooth wear and feeding ecology in mountain gorillas from Volcanoes National Park, Rwanda
OBJECTIVES: Ecological factors have a dramatic effect on tooth wear in primates, although it remains unclear how individual age contributes to functional crown morphology. The aim of this study is to determine how age and individual diet are related to tooth wear in wild mountain gorillas (Gorilla beringei beringei) from Volcanoes National Park, Rwanda. MATERIAL AND METHODS: We calculated the percent of dentine exposure (PDE) for all permanent mo…
Faster growth corresponds with shallower linear hypoplastic defects in great ape canines
Unexpected terrestrial hand posture diversity in wild mountain gorillas
OBJECTIVES: Gorillas, along with chimpanzees and bonobos, are ubiquitously described as 'knuckle-walkers.' Consequently, knuckle-walking (KW) has been featured pre-eminently in hypotheses of the pre-bipedal locomotor behavior of hominins and in the evolution of locomotor behavior in apes. However, anecdotal and behavioral accounts suggest that mountain gorillas may utilize a more complex repertoire of hand postures, which could alter current inte…
A radiographic study of permanent molar development in wild Virunga mountain gorillas of known chronological age from R wanda
OBJECTIVES: While dental development is important to life history investigations, data from wild known-aged great apes are scarce. We report on the first radiographic examination of dental development in wild Virunga mountain gorillas, using known-age skeletal samples recovered in Rwanda. MATERIALS AND METHODS: In 43 individuals (0.0-14.94 years), we collected radiographs of mandibular molars, and where possible, cone beam CT scans. Molar crown a…
Lifetime reproductive success of female mountain gorillas
Studies of lifetime reproductive success (LRS) are important for understanding population dynamics and life history strategies, yet relatively little information is available for long-lived species. This study provides a preliminary assessment of LRS among female mountain gorillas in the Virunga volcanoes region. Adult females produced an average of 3.6 ± 2.1 surviving offspring during their lifetime, which indicates a growing population that con…
Habitat Use and Structural Preferences of Captive Western Lowland Gorillas (Gorilla gorilla gorilla(: Effects of Environmental and Social Variables
Intragroup Behavioral Changes Following Intergroup Conflict in Mountain Gorillas (Gorilla beringei beringei)
Brain organization of gorillas reflects species differences in ecology
Gorillas include separate eastern ( Gorilla beringei ) and western ( Gorilla gorilla ) African species that diverged from each other approximately 2 million years ago. Although anatomical, genetic, behavioral, and socioecological differences have been noted among gorilla populations, little is known about variation in their brain structure. This study examines neuroanatomical variation between gorilla species using structural neuroimaging. Postmo…
Nest Building in Captive Gorilla gorilla gorilla
Infant handling by female mountain gorillas: Establishing its frequency, function, and (ir)relevance for life history evolution
OBJECTIVES: Infant handling describes cases in which youngsters are temporarily removed from the care of their mothers and "taken care of" (held, carried, etc.) by other conspecifics. Handlers may gain indirect fitness benefits from these actions and can practice mothering skills, thereby improving the odds of survival of their own infants. Great apes are notable for displaying little infant handling. Apart from anecdotal observations, no publish…
Incisor tooth wear and age determination in mountain gorillas from Volcanoes National Park, Rwanda
OBJECTIVES: Ecological factors, but also tooth-to-tooth contact over time, have a dramatic effect on tooth wear in primates. The aim of this study is to test whether incisor tooth wear changes predictably with age and can thus be used as an age estimation method in a wild population of mountain gorillas (Gorilla beringei beringei) from Volcanoes National Park, Rwanda. MATERIALS AND METHODS: ) as a proxy for incisal macrowear. Linear and quadratic…
Functional evidence for differences in sperm competition in humans and chimpanzees
Sperm competition occurs when the gametes of or more males compete for opportunities to fertilize a given set of ova. Previous studies have demonstrated that certain morphological characteristics are affected by sperm competition intensity (e.g. relative testes size and sperm midpiece volume). This study examined whether aspects of sperm energetics may also be affected by sexual selection. We compared the membrane potential of mitochondria in liv…
Spontaneous tool use in captive, free-ranging golden lion tamarins (Leontopithecus rosalia rosalia)
Habitat Use and Structural Preferences of Captive Western Lowland Gorillas (Gorilla gorilla gorilla(: Effects of Environmental and Social Variables
Proximity patterns of female western lowland gorillas ( Gorilla gorilla gorilla ) during the six months after parturition
Studies of wild mountain gorillas have demonstrated strong preferences among new mothers for the silverback. Protection against infanticide has been theorized to be the primary cause for this attraction. We examined social partner preferences in captive western lowland mothers during the 6 mo after parturition and found that juveniles and females were the primary members of the new mothers' social network. Mothers spent significantly more time in…
Nest Building in Captive Gorilla gorilla gorilla
Program and Conference Schedule
Changes in locomotor and foraging skills in captive‐born, reintroduced golden lion tamarins ( Leontopithecus rosalia rosalia )
The behavior of reintroduced, captive‐born animals is understudied, limiting the scientific understanding and utility of reintroduction as a conservation tool. This work describes changes in locomotor and foraging behaviors in captive‐born golden lion tamarins over the first 18 months after their release into the wild. The subjects included 73 individuals living in and around the Poco das Antas Biological Reserve in Brazil between 1984 and 1996. …
Postconflict behavior in captive western lowland gorillas (Gorilla gorilla gorilla)
Postconflict (PC) behaviors, including reconciliation and consolation, have been observed in many primate and several nonprimate species. Using the PC-matched control (MC) method, PC behavior was examined in two groups (n=13) of captive western lowland gorillas, a species for which no conflict resolution data have been published. Analyses of 223 conflicts showed significantly more affiliation between former opponents after a conflict when compare…
Differential use of attentional and visual communicative signaling by orangutans (Pongo pygmaeus) and gorillas (Gorilla gorilla) in response to the attentional status of a human
In this study we investigated the communicative abilities of 10 orangutans (Pongo pygmaeus) and seven western lowland gorillas (Gorilla gorilla gorilla), and particularly focused on their sensitivity to the attentional state of a human experimenter when choosing from a repertoire of both auditory and visual communication strategies. In experiment 1 a banana was placed in front of the subject's cage and a human experimenter was either present or a…
Functional evidence for differences in sperm competition in humans and chimpanzees
Sperm competition occurs when the gametes of or more males compete for opportunities to fertilize a given set of ova. Previous studies have demonstrated that certain morphological characteristics are affected by sperm competition intensity (e.g. relative testes size and sperm midpiece volume). This study examined whether aspects of sperm energetics may also be affected by sexual selection. We compared the membrane potential of mitochondria in liv…
Sexual behavior in female western lowland gorillas ( Gorilla gorilla gorilla ): Evidence for sexual competition
Previous research in gorillas suggests that females engage in post‐conception mating as a form of sexual competition designed to improve their own reproductive success. This study focused on sexual behaviors in a newly formed group of western lowland gorillas ( Gorilla gorilla gorilla ) housed at Zoo Atlanta. All females engaged in mating outside their conceptive periods, although there was individual variation in the frequency of the behavior. A…
Male–immature relationships in multi‐male groups of mountain gorillas ( Gorilla beringei beringei )
We examined the pattern and possible functions of social interactions between adult males and immatures in three free‐ranging, multi‐male groups of mountain gorillas ( Gorilla beringei beringei ). Previous studies conducted during the 1970s when groups contained one to three adult males concluded that male–immature relationships were likely to be a form of low‐cost paternal investment [Stewart, Mountain gorillas: three decades of research at Kari…
Lifetime reproductive success of female mountain gorillas
Studies of lifetime reproductive success (LRS) are important for understanding population dynamics and life history strategies, yet relatively little information is available for long-lived species. This study provides a preliminary assessment of LRS among female mountain gorillas in the Virunga volcanoes region. Adult females produced an average of 3.6 ± 2.1 surviving offspring during their lifetime, which indicates a growing population that con…
Generation times in wild chimpanzees and gorillas suggest earlier divergence times in great ape and human evolution
Fossils and molecular data are two independent sources of information that should in principle provide consistent inferences of when evolutionary lineages diverged. Here we use an alternative approach to genetic inference of species split times in recent human and ape evolution that is independent of the fossil record. We first use genetic parentage information on a large number of wild chimpanzees and mountain gorillas to directly infer their av…
Using Technology to Educate Zoo Visitors About Conservation
Zoos are in a unique position to educate the public about conservation issues. To improve public education practices, it is important to understand how various educational techniques influence visitor learning and experience at the zoo. Therefore, we studied the effects of 3 educational conditions on visitor behavior and knowledge at the Zoo Atlanta orangutan exhibit: no presentation, a video presentation, and a live presentation. Stay time data …
Early Brain Growth Cessation in Wild Virunga Mountain Gorillas ( Gorilla beringei beringei )
Understanding the life history correlates of ontogenetic differences in hominoid brain growth requires information from multiple species. At present, however, data on how brain size changes over the course of development are only available from chimpanzees and modern humans. In this study, we examined brain growth in wild Virunga mountain gorillas using data derived from necropsy reports ( N = 34) and endocranial volume (EV) measurements ( N = 86…
Can Black‐and‐White Ruffed Lemurs ( Varecia variegata ) Solve Object Permanence Tasks
We examined object permanence in black‐and‐white‐ruffed lemurs ( Varecia variegata) at Zoo Atlanta. A series of visible and invisible displacement tasks with suitable controls were presented to five adult subjects. Subjects performed significantly above chance on all regular tasks, except for the double invisible displacements. Subjects failed visible and invisible controls. Failure on the control trials did not appear to be because subjects used…
Variability in the developmental life history of the genus Gorilla
Life history is influenced by factors both intrinsic (e.g., body and relative brain size) and extrinsic (e.g., diet, environmental instability) to organisms. In this study, we examine the prediction that energetic risk influences the life history of gorillas. Recent comparisons suggest that the more frugivorous western lowland gorilla shows increased infant dependence, and thus a slower life history, than the primarily folivorous mountain gorilla…
Double invisible displacement understanding in orangutans: Testing in non-locomotor and locomotor space
Mountain gorilla ranging patterns: Influence of group size and group dynamics
Since the 1980s, the Virunga mountain gorilla population has almost doubled, now reaching 480 individuals living in a 430-km(2) protected area. Analysis of the gorillas' ranging patterns can provide critical information on the extent and possible effects of competition for food and space. We analyzed 12 years of daily ranging data and inter-group encounter data collected on 11 gorilla groups monitored by the Karisoke Research Center in Rwanda. Du…
Age‐related motor dysfunction: Manual slowing in Gorilla gorilla gorilla
Aging in humans and rhesus monkeys is commonly associated with motor function decrements including dexterity, speed, and strength. Despite their longevity and phylogenetic relatedness to humans, the effects of aging on motor function in non-human apes have been minimally studied. We conducted two experiments with western lowland gorillas (11-54 years of age) to determine whether aged gorillas exhibit motor deficits similar to those seen in other …
Energetic responses to variation in food availability in the two mountain gorilla populations ( Gorilla beringei beringei )
OBJECTIVE: Here, we compare food availability and relate this to differences in energy intake rates, time spent feeding, and daily travel distance of gorillas in the two populations. Comparative intraspecific studies investigating spatiotemporal variation in food availability can help us understand the complex relationships between ecology, behavior, and life history in primates and are relevant to understanding hominin evolution. Differences in …
Brain organization of gorillas reflects species differences in ecology
Gorillas include separate eastern ( Gorilla beringei ) and western ( Gorilla gorilla ) African species that diverged from each other approximately 2 million years ago. Although anatomical, genetic, behavioral, and socioecological differences have been noted among gorilla populations, little is known about variation in their brain structure. This study examines neuroanatomical variation between gorilla species using structural neuroimaging. Postmo…
Group structure predicts variation in proximity relationships between male–female and male–infant pairs of mountain gorillas (Gorilla beringei beringei)
Validation of two independent photogrammetric techniques for determining body measurements of gorillas
The ability to accurately measure morphological characteristics of wild primates in the field is challenging, yet critical for understanding fundamental aspects of their biology and behavior. Recent studies have shown that digital photogrammetry can be used to non‐invasively measure morphological traits of wild primates, as it allows for the determination of geometric properties of objects remotely from photographic images. We report here on a ra…
Age‐related changes in molar topography and shearing crest length in a wild population of mountain Gorillas from Volcanoes National Park, Rwanda
OBJECTIVES: Great ape teeth must remain functional over long lifespans. The molars of the most folivorous apes, the mountain gorillas, must maintain shearing function for 40+ years while the animals consume large quantities of mechanically challenging foods. While other folivorous primates experience dental senescence, which compromises their occlusal surfaces and affects their reproductive success as they age, it is unknown whether dental senesc…
Biology (38 works) · Primate Behavior and Ecology (35 works) · Gorilla (28 works) · Ecology (21 works) · Zoology (21 works) · Geography (15 works) · Demography (14 works) · Ecology (14 works) · Psychology (12 works) · Animal Behavior and Reproduction (11 works)