Tara S. Stoinski

A preliminary study of the behavioral effects of feeding enrichment on African elephants.

Although commonly practiced with many species, feeding enrichment in elephants is understudied. The behavioral effects of feeding enrichment were tested in three African elephants by substituting an equal dry weight of browse for hay in an ABA design. The results showed a significant increase in feeding and significant decreases in drinking and inactivity when the browse was present. Additionally, changes in feeding, inactivity, and time spent in contact were observed outside the time the browse was actually presented, although the relationship of these changes to the experimental methodology is unknown. A significant increase in visibility to zoo visitors during the browse conditions demonstrates that browse is an effective, naturalistic method for increasing visibility as well as species-typical behaviors. Managers of captive elephants should consult with a nutritionist to address issues of energetics, nutritional content, and secondary compounds when using browse as feeding enrichment. Zoo Biol 19:485-493, 2000. Copyright 2000 Wiley-Liss, Inc.

Nocturnal behavior in a group of unchained female African elephants

The chaining of elephants at night is a common management strategy in zoos, yet the costs and benefits of such a strategy are relatively unknown. A study of three unchained female African elephants was undertaken to document their nocturnal behavior. The subjects were observed between the hours of 1800 and 0800 for 10 weeks in the summer of 1992 (total of 172 hr) and 14 weeks in the summer of 1994 (total of 153 hr). Scan data were collected every 5 min to gather information on activity budgets, social proximity, and space utilization. All-occurrence data were collected on social and non-social behaviors. In each year of the study, the subjects spent equivalent amounts of time eating, lying, standing, and walking. Additionally, subjects spent half of their time within one body length of another animal and utilized all three available enclosures. Social and non-social behaviors were frequent, and these data plus the activity profiles reveal the animals generally were most active between the hours of 1800 and 2400 and 0600 and 0700. The findings suggest that the use of no restraints is currently an effective strategy for this elephant group. The high activity levels observed during many of the early evening hours suggest that zoos could permit increased activity and social interactions by extending the hours when the elephants are unchained. Zoo Biol 18:101–109, 1999.

Habitat Use and Structural Preferences of Captive Western Lowland Gorillas (Gorilla gorilla gorilla(: Effects of Environmental and Social Variables

Exhibit naturalism has become the architectural standard for new zoo exhibits, yet our scientific understanding of how animals interact with naturalistic environments is very limited. Given the expense incurred in building new exhibits, it is essential that more information on animal-environment interactions be obtained and that it be incorporated at the outset into exhibit designs. We documented four years of habitat use and structural preferences of western lowland gorillas at Zoo Atlanta. We found that quality of space rather than quantity of space was important, as subjects spent 50% of their time in <15% of the exhibits. Subjects showed strong preferences for the areas near structures, particularly the holding building, and spent significantly less time away from structures than expected. Temperature interacted with structural preferences in that the subjects spent more time away from structures when temperatures were cold and more time near them when temperatures were hot. There was no difference in habitat use and structural preferences due to age, sex, and rearing history, but social factors appear to play a role. Our results are similar to those found a decade earlier in the same population and to other studies of space use in apes but are the first to include significant temperature effects. Additionally, they suggest that managers and designers need to take into account factors such as quality of space, attractiveness of the holding building, and the interaction of structural preferences with variables such as temperature and social factors when designing exhibits.

A survey of research in North American zoos and aquariums

To assess the current status of research in zoos and aquariums, a 36-item survey, which replicated and expanded upon an earlier survey [Finlay and Maple, 1986], was sent to 173 American Zoo and Aquarium Association (AZA) institutions. A response rate of 71% was achieved after a second mailing. The results show that the role of research in AZA institutions has increased in the last decade. The percentage of zoos and aquariums that report conducting research, that list research as an objective of the institution, and that have a research committee/department have all increased. The number of individuals involved in research per institution has approximately doubled since 1986, and slightly less than half of responding institutions currently have a full-time position dedicated to administering research. Lack of available funds, time, and qualified personnel are the most common reasons reported for not conducting research. Zoo Biol 17:167–180, 1998.

Relative numerousness judgment and summation in young, middle-aged, and older adult orangutans (Pongo pygmaeus abelii and Pongo pygmaeus pygmaeus).

The ability to select the larger of two quantities ranging from 1 to 5 (relative numerousness judgment [RNJ[) and the ability to select the larger of two pairs of quantities with each pair ranging from 1 to 8 (summation) were evaluated in young, middle-aged, and older adult orangutans (7 Pongo pygmaeus abelii and 2 Pongo pygmaeus pygmaeus). Summation accuracy and RNJ were similar to those of previous reports in apes; however, the pattern of age-related differences with regard to these tasks was different from that previously reported in gorillas. Older orangutans were less accurate than the young and middle-aged for RNJ, and summation accuracy was equivalent among age groups. Evidence was found to suggest that the young and middle-aged based their selection of the largest quantity pair on both quantities within each pair during the summation task. These results show a relationship between subject age and the quantitative abilities of adult orangutans.

Observational learning in orangutan cultural transmission chains

Field reports suggest that orangutans acquire local traditions by observing neighbouring conspecifics. However, there is little direct evidence of social learning to support this conclusion. The present study investigated whether orangutans would learn a novel foraging method through observation of a conspecific in a diffusion-chain paradigm testing for the spread of the behaviour. A foraging box with two possible methods for extracting food was used to investigate the transmission of a foraging tradition among zoo-living subjects. In a socially housed group of five orangutans, the dominant male was trained to use one technique exclusively to retrieve food. He then performed this technique in the presence of another group member, who was then allowed to forage. After several trials, the observer became the model for the next individual. A second experimental group of six individuals was introduced to the alternative method. The model-seeded technique was successfully transmitted along both experimental chains, with significant preferences for the model method. These results are consistent with claims for social transmission of foraging methods in wild orangutans.

Nest building in captive Gorilla gorilla gorilla

Although various aspects of gorilla nest building have been described in wild populations, nest-building behavior of captive gorillas has not been subject to much scientific review. We observed nest building in 17 gorillas during three periods: summer baseline, winter baseline, and winter treatment, in which the amount of available nesting material was doubled. We conducted observations exclusively in the indoor holding area in the hour following evening departure of animal care staff. During baseline, gorillas engaged in nest-building on 3.1% of scans and were on a constructed nest on 27.9% of scans. Overall, gorillas spent significantly more time on elevated nests than on floor nests. There were no statistically significant sex, age class, or rearing history differences in nest building, time spent on a nest, or nest location preference. Nest building consisted of both gathering and manipulating materials. The gorillas spent significantly more time building nests in winter than in summer. Additionally, they were more often on elevated nests during winter than summer. Doubling the amount of nesting material did not increase nest building, but it increased the number of floor nests. Our results suggest that providing adequate materials to captive gorillas for nest building may facilitate performance of species-typical nest-building, minimize competition among individuals for nesting sites and materials, and permit individual thermoregulation.

The Effect of Structural Preferences, Temperature, and Social Factors on Visibility in Western Lowland Gorillas (Gorilla G. Gorilla)

Postoccupancy evaluations are common in determining successful design elements in the human setting, but they are rarely employed in zoological parks. The current study evaluated how structural preferences, temperature, and social factors affected the visibility of four groups of gorillas to the public. Although the majority of structures were located in visible portions of the exhibit, structures had a negative effect on visibility because of the gorillas’ strong preference for a single typeof structure(buildings) located primarily in nonvisibleparts of theexhibits. Tem perature and visibility were linearly related, with increasing temperatures corresponding with decreasing visibility. The removal of an animal from the group significantly affected the visibility of the remaining group members. The authors’ results reinforce the need for exhibit designers to consider the relationships between animal behavior and environmental variables and to work with captive managers to create exhibits that meet the needs of individual animals.