Variables that influence the activity of captive orangutans

It is well known that the environment significantly influences the behavior of captive animals. However, the specific nature of the cues that promote speciestypical behavior patterns is not usually known. This study extends an earlier investigation by Wilson (Zoo Biology 1: 201–209, 1982). The objective was to identify and quantify specific environmental components that influence activity levels in orangutans. Six enclosure variables were quantified, and activity levels measured, for 29 orangutans housed in nine zoological parks. Multiple regression analysis indicated that the combination of the number of animals, amount of usable surface area, number of movable objects, and enclosure volume was the best predictor of activity levels, accounting for 58% of the variance in activity levels. It was concluded that the provision of large enclosures, containing large numbers of movable objects and providing social opportunities, would promote higher levels of activity in captive orangutans. © 1992 Wiley-Liss, Inc.     

Growth and sexual dimorphism in orangutan crania: a three-dimensional approach

New insights may be gleaned by taking an ontogenetic approach to investigations of adult dimorphism. Previous work in this area relied on traditional, caliper-based, morphometric methods, and produced conflicting results. This study uses a three-dimensional (3-D) approach for both local and global form comparisons of sex-specific growth and growth patterns. 3-D coordinate data were collected for 20 landmarks on 94 orangutan crania divided into five developmental stages. Data were analyzed using Euclidean distance matrix analysis (EDMA). Results indicate that differences in growth patterns between male and female orangutans exist in the youngest age intervals. Dimorphic patterns are strongest in the face and basicranium at the youngest age intervals, and in the face and neurocranium during adult stages. Females grow substantially more in the cranial base and face during the youngest age groups, while males grow more than females in all anatomical regions later in development. Growth in the palate was similar between sexes. Sexual dimorphism may be produced through the continued growth of one sex relative to the other, representing differences in timing, or growth duration. Dimophism may also result from different growth rates between sexes, where one sex develops faster than the other sex in the same time interval. Orangutan males and females differ in both the rate and duration of their craniofacial development. The data analysis technique used here, EDMA, was integral in identifying dynamic growth processes rather than just the static end results of each developmental stage.     

Aspects of dental development in the orangutan prior to eruption of the permanent dentition

In spite of a resurgence of interest in the interpretation of the sequences of dental development and eruption in various Plio-Pleistocene hominoids as being either “modern human” or “ape-like,” the body of comparative material on the extant hominoids remains deficient in critical areas. In concert with recent attempts to rectify this situation, we present the results of our studies on dental morphogenesis in the orangutan. We have focused on the growth and eruption of the deciduous dentition as well as early stages of permanent tooth formation and have found that 1) many permanent teeth develop earlier than was thought, 2) differences exist between development in the upper and in the lower jaw, and 3) states of tooth formation can vary significantly among individuals of similar chronological age or tooth eruption status.     

The behavior of a zoo-housed infant orangutan after the death of its mother

The behavior of an infant female orangutan at Dublin Zoo before and after the death of her mother was recorded using scan sampling and compared. Social interactions and associations of the infant with the other individuals in the group were also compared before and after the death of her mother. Increases in climbing and object manipulation were observed, and a decrease in resting occurred. The infant orangutan significantly increased the amount of time she spent in close contact with another related adult female in the group after her mother's death. This case study describes an example of a zoo‐housed infant orangutan being successfully fostered by a related female without human intervention. It also provides a quantification of the behavior of an infant orangutan before and after being orphaned. Zoo Biol 30:205–211, 2011. © 2010 Wiley‐Liss, Inc.     

Sexual resurgence and possible induction of reproductive synchrony in a captive group of orangutans

In April 1985, a 22-year-old group-living female orangutan gave birth to her second infant, marking an interbirth interval of 12 years, 2 months. The timing and patterning of sexual activity displayed by the group of two females and one male over a 3-year period were analyzed to identify variables that might account for this female's sexual resurgence. Variables considered were (1) movement to a new habitat, (2) opening of a vaginal stricture, (3) addition of a second female to the group, (4) male sexual resurgence, and (5) copulatory synchrony. None of these variables alone could account for the resurgence of fertility, although several of them account for the increase in copulatory frequency. This suggests that a combination of factors may be operating, including the induction of fertility via the presence of another cycling female. This induction effect has been described for rhesus macaques, and since this orangutan group meets the conditions necessary for such an induction effect, it is offered as another possible variable influencing fertility. Indices of pregnancy determination, as they relate to gestation lengths and prematurity of infants, also are evaluated and compared.     

A possible case of hantavirus infection in a Borneo orangutan and its conservation implication

Background Natural infection of hantavirus in orangutans has never been reported. Methods Enzyme‐linked immunosorbent assays (ELISA), Indirect immunofluorescence assay (IFA), and RT‐PCR were used to diagnosis a suspected case in a pet orangutan in southern Taiwan. Results Although the RT‐PCR result was negative, the high IgG titer in the beginning and its dramatic drop after treatments suggested a recent Seoul‐type hantavirus infection. Conclusions Hantavirus transmission and its potential damage to wild orangutans should not be overlooked.     

Lethal intragroup aggression by adult male spider monkeys (Ateles geoffroyi)

I report three cases of coalitionary aggression by adult male black-handed spider monkeys (Ateles geoffroyi) against subadult males within their community on Barro Colorado Island (BCI), Panama. Two of these cases were followed by the disappearance and presumed death of the victim. Similar behavior was recently reported by Valero et al. [in press], who suggested that this behavior may be the result of intense male reproductive competition. Like the single instance they reported, the cases I report all occurred when the operational sex ratio was approximately 1:1, which suggests that intense competition among males for access to reproductively viable females may be a contributing factor. Additionally the very low density of spider monkeys on BCI may play a significant role in the occurrence of this lethal aggression. Large numbers of adult males are not necessary to protect a territorial boundary against neighboring groups, and additional males may act merely as mating competition.     

Notes on water-contact by a captive male lowland gorilla

Great apes in captivity and in the wild exhibit varying propensities to enter and use water. Although some captive apes have drowned in deep water, others have been inclined to play and to “bathe” in shallow water. In the present study of two gorillas, an adult male's water contact was apparently influenced by humidity, but not by zoo attendance or ambient temperature. Most water contact was restricted to the morning hours; water entry during the afternoon was infrequent. Both animals sought shelter during rain. Considering the frequent use of the streams and moat by one of the two gorillas studied, water may be regarded as a type of environmental enrichment.     

Social behavior of captive,group-living Orangutans

The behavior of orang-utans (Pongo pygmaeus)was observed in two captive groups (one adult group, one juvenile group). Activity profiles,animal interactions, and compartmental spatial use for both adult-group and juvenile-group individuals were recorded over a 9-month period. Behavioral repertoires for both groups included large amounts of social activity. Equivalent amounts of social activity were found for each group. The social behavior of juvenile animals involved more active behavior such as play. The social behavior of the adult animals was more subtle, involving social monitoring and allogrooming. These results indicate that orangutans, at least when group-living in captivity, exhibit the potential to display social behavior which is apparently of greater frequency and complexity than that which has been observed in the wild. These findings suggest that the solitary behavior of wild orangutans is not a necessary characteristic of orangutan behavior. Under different environmental conditions orangutans appear to readily adapt socially, and, like other nonhuman primates,they have the capacity to exhibit complex and subtle social behavior. This report is based on part of a senior thesis submitted by Sara D. Edwards     

Developmental changes in the facial morphology of the Borneo orangutan (Pongo pygmaeus): possible signals in visual communication

Orangutans display remarkable developmental changes and sexual differences in facial morphology, such as the flanges or cheek-pads that develop only on the face of dominant adult males. These changes suggest that facial morphology is an important factor in visual communication. However, developmental changes in facial morphology have not been examined in detail. We studied developmental changes in the facial morphology of the Borneo orangutan (Pongo pygmaeus) by observing 79 individuals of various ages living in the Sepilok Orangutan Rehabilitation Centre (SORC) in Malaysia and in Japanese zoos. We also analyzed photographs of one captive male that were taken over a period of more than 16 years. There were clear morphological changes that occurred with growth, and we identified previously unreported sexual and developmental differences in facial morphology. Light-colored skin around the eyes and mouth is most prominent in animals younger than 3 years, and rapidly decreases in area through the age of approximately 7 years. At the same time, the scattered, erect hairs on the head (infant hair) become thick, dense hairs lying on the head (adult hair) in both sexes. The results suggest that these features are infant signals, and that adult signals may include darkened face color, adult hair, whiskers, and a beard, which begin to develop after the age of approximately 7 years in both sexes. In females, the eyelids remain white even after 10 years, and turn black at around the age of 20; in males, the eyelids turn black before the age of 10. The whiskers and beards of adults are thicker in males than in females, and are fully developed before the age of 10 in males, while they begin to develop in females only after approximately 20 years. White eyelids and undeveloped whiskers and beards may be visual signals that are indicative of young adult females. Our results also show that the facial morphology of the unflanged male is similar to that of the adult female, although it has also been pointed out that unflanged males resemble younger individuals.     

Hormone levels and overt social behaviors,including signed output,in a captive lowland gorilla

An investigation into the relationship between a 10-yr-old captive female gorilla's hormonal fluctuations and her overt behaviors was conducted for a 6-mo period during daily, 30-min, midday sample sessions. During each session a urine sample was collected from the gorilla and a total immunoreactive estrogen assay (E_t) was performed to obtain combined levels of estrone, estradiol, and estriol. Additionally, 38 behavioral variables were recorded on check sheets. Nearly 50% of these variables were significantly (P ≤ .05) correlated with the ape's hormone levels, thus suggesting that non-sexual overt behaviors may act as indicators of an ape's reproductive status.     

Social interactions and solitary behaviors in a pair of captive sand cats (Felis margarita)

This study examined the behavior and activity of two captive sand cats at the Washington Park Zoo in Portland, Oregon. Sex differences in behavior were examined and the direction and frequency of social interactions were determined. An attempt was made to determine behavioral signs of estrus. A scan sampling data collection technique was used to find the percentage of time spent by each cat in each behavior. Simultaneously, the frequency of social behaviors was recorded. The cats spent the greatest percentage of their time pacing and resting; social interactions occurred very infrequently. The only significant sex difference in behavior was that the male marked and urinated/defecated more than did the female. Temporal distribution in the usage of the enclosure was examined. It was found that when one cat was active, the other tended to be inactive. No overt behavioral signs of estrus were evident other than the actual observance of copulation. However, the percentage of time spent in each behavior was examined when the female was assumed to be in estrus (days when copulation was observed) versus nonestrous periods. The female was found to pace and locomote significantly more during estrous periods.     

Behavioral response of captive western lowland gorillas (Gorilla gorilla gorilla) to the death of silverbacks in multi‐male groups

In both free‐ranging and captive western lowland gorillas, a silverback provides protection and leadership, mediating conflict within a group. In the wild, when a dominant silverback dies the group will disperse or transfer to a solitary male, unless a subsequent male is present to inherit the group. In captivity, studies have focused on groups containing one male and therefore it is unclear how gorillas respond to the death or removal of a silverback in multi‐male groups. This study examined the behavior of a bachelor group (Cleveland Metroparks Zoo) and a multi‐male, mixed‐sex group (Pittsburgh Zoo and PPG Aquarium) following the death of two older silverbacks in 2005. Both of the younger but dominant males maintained their same level of dominance after the death. We predicted that agonism would increase after the death as groups struggled for social stablility. We did observe an increase in both agonism and displacements among the bachelor group, but only observed an increase in displacements among the mixed‐sex group. Although we predicted that there would be no change in solitary behavior, both groups decreased feeding and the mixed‐sex group increased self‐directed behavior post‐death. In the bachelor group, self‐directed behavior decreased and undesirable behavior increased. We also observed a difference in spatial distance after the death with members of the mixed‐sex group becoming more dispersed and members of the bachelor group more converged. This study demonstrates that there is a period of transition for multi‐male groups after the death or removal of the oldest silverback. Future research could integrate physiological measures with behavioral analyses before and after the death or removal of a prominent member of the group. Zoo Biol 29:16–29, 2010. © 2009 Wiley‐Liss, Inc.     

Orangutan use of vertical space in an innovative habitat

This study measured use of vertical space in an innovative habitat for three adolescent orangutans (Pongo pygmaeus). The indoor habitat was innovative in two main ways: a flooded floor and retractable skylights. It included four large molded trees and interwoven vines throughout 1,620 m³ of space. The exhibit was divided into four vertical levels: skylights, upper canopy, lower canopy, and flooded floor. Five trained observers made instantaneous scans of the exhibit every 5 minutes, in 1‐hour blocks of time over a 10‐month period, logging 180 hours of observations. One location (of 55) and one behavior (of 53) were noted at each interval. Behaviors were collapsed to form five categories: solitary inactivity, solitary activity, social inactivity, social activity, and eating/drinking. Results showed the orangutans favored the upper canopy, which contained many tree limbs for sitting and reclining. The orangutans next favored the lower canopy and the skylights, especially those skylights that were out of public view. The habitat’s flooded floor was avoided (they used it just 1% of the time), as planned by the exhibit designers who intended to showcase these arboreal primates in trees, not on the ground. When compared with wild orangutans, we considered few of their behaviors to be atypical: foraging/eating plastic (vines) and stereotyped behaviors. Overall, the unique design of the habitat provided opportunities for a range of species‐typical behaviors, varying by vertical level, demonstrating the importance of providing sufficient vertical space for orangutans. Zoo Biol 19:239–251, 2000. © 2000 Wiley‐Liss, Inc.     

Reproduction in free-ranging male Propithecus verreauxi: The hormonal correlates of mating and aggression

Endocrine studies of captive strepsirrhine primates suggest that physical environment and social factors mediate inter-individual variations in testicular function and serum testosterone (sT) in males. While these studies have made major contributions to our understanding of the individual proximate mechanisms influencing androgen activity in male strepsirrhines, none have investigated how these mechanisms work coincidentally in free-ranging populations. In this study we used fecal steroid analysis to examine androgen-behavior interactions associated with reproduction in free-ranging male Propithecus verreauxi. Behavioral and hormone data were collected from two social groups during the 1990–91 and 1991–92 breeding seasons at Beza Mahafaly, Madagascar. Solid phase and radioimmunoassay techniques were used to quantify testosterone (T) in 105 desiccated fecal samples collected weekly from seven males. Results suggest that 1) solid phase extraction and radioimmunoassay techniques were reliable and accurate methods for quantifying T in sifaka feces; 2) fecal T (fT) elevations spanned a minimum of 4 months, peak levels occurring 1 month prior to the January onset of the breeding season; 3) fecal T concentrations were influenced by developmental factors and, among mature males, social factors associated with rank, intergroup aggression, and group instability. Am J Phys Anthropol 105:137–151, 1998. © 1998 Wiley-Liss, Inc.     

Primary observations on rutting behavior of the captive red goral

The rutting behavior of the red goral (Naemorhedus cranbrooki) was studied at the Breeding Center of Shanghai Zoo from September 16–November 21, 2004. Twenty‐three qualitatively distinct behavior patterns was observed. Males showed a more extensive repertoire (18 patterns, 15 carried out only by males) than did females (10 patterns, 6 carried out only by females). Smelling and licking behavior was used most by males, whereas escape was used most by females. Zoo Biol 0:1–7, 2006. © 2006 Wiley‐Liss, Inc.     

Time-budgets and activity patterns of captive Sunda pangolins (Manis javanica)

This is the first assessment of Manis javanica behavior in captivity. The aim of the investigation was to assess behavior in order to suggest ways of improving captive care and management of the species. This was undertaken by constructing time-budgets and activity patterns and identifying any abnormal repetitive behavior (ARB) exhibited. Scan and focal animal sampling were implemented in observations of seven subjects. Analyses detailed idiosyncrasies in how subjects partitioned their active time. Peak activity occurred between 18:00 and 21:00 hr. Two ARBs, clawing and pacing, were identified and the cessation of clawing in one subject was possible by modifying its enclosure. Stress-related behavior, understood to be related to several factors, means maintaining this species in captivity remains problematic. Recommendations are made pertaining to husbandry, captive management, and future research.     

Use of limestone karst forests by Bornean orangutans (Pongo pygmaeus morio) in the Sangkulirang peninsula, east Kalimantan, Indonesia

The Indonesian province of East Kalimantan is home to some of the largest remaining contiguous tracts of lowland Dipterocarp forest on the island of Borneo. Nest surveys recently conducted in these forests indicated the presence of a substantial population of Eastern Bornean orangutans (Pongo pygmaeus morio) in the Berau and East Kutai regencies in the northern half of the province. The Sangkulirang Peninsula contains extensive limestone karst forests in close proximity to the lowland Dipterocarp forests inhabited by orangutans in these regencies. Orangutans have been sighted in these limestone karst forests, but the importance of this forest type for orangutans has been unclear. Therefore, we conducted 49 km of nest surveys in limestone karst forest to obtain the first quantitative estimates of orangutan densities in this habitat, and walked 28 km of surveys in nearby lowland Dipterocarp forests for comparison. We also gathered basic ecological data along our transects in an attempt to identify correlates of orangutan abundance across these habitat types. Undisturbed limestone karst forests showed the lowest orangutan densities (147 nests/km(2), 0.82 indiv/km(2)), disturbed limestone forests had intermediate densities (301 nests/km(2), 1.40 indiv/km(2)), and undisturbed lowland Dipterocarp forests contained the highest density (987 nests/km(2), 5.25 indiv/km(2)), significantly more than the undisturbed limestone karst forests. This difference was not correlated with variation in liana abundance, fig stem density, or stump density (an index of forest disturbance). Therefore, other factors, such as the relatively low tree species diversity of limestone karst forests, may explain why orangutans appear to avoid these areas. We conclude that limestone karst forests are of low relevance for safeguarding the future of orangutans in East Kalimantan.     

Reunion displays in captive male brown capuchins (Cebus apella)

Separation and subsequent reintroduction of brown capuchins (Cebus apella) can lead to reunion displays during which individuals will embrace and emit high-pitched, loud vocalizations. These displays were investigated in three male capuchins: two adults and one juvenile. These subjects were part of a larger captive social group held at the Capuchin Laboratory, Hiram College, OH, USA. We hypothesized that males would engage in reunion displays following separation regardless of the order of reintroduction, as evidence of an affiliative bond judged by concurrent social behavior. Sixty separations were conducted as part of weekly husbandry over a period of 13 months. Occurrence of reunion displays between the males was recorded with the initiator also noted. Reunion displays among males were found to occur only between the juvenile and alpha male, and all displays were initiated by the juvenile. Displays were highly influenced by the order of reintroduction. We suggest that reunion displays operate to reaffirm social relationships, particularly during situations of social tension.