Spotlight on Zoo Science
October 20, 2004
Teasing Apart Panda Temperament
Zoo scientists find that "personality" counts when it comes to successful breeding in giant pandas.
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| Temperament seems to influence the likelihood of breeding in zoo giant pandas. |
Historically, the breeding success of giant pandas in zoos and breeding centers has not been good. In fact, to this day there is not one self-sustaining giant panda population in captivity. But National Zoo research associates David Powell, Devra Kleiman, and their colleagues have recently taken a new approach in their investigation of this difficult issue.
They looked for connections between panda temperament, or what a human might call personality, and reproductive behavior. They also studied the effects of panda housing and husbandry on the animals’ temperaments to gain more insight into their reproductive behavior.
The study of animal temperament and its effect on animal behavior is part of a growing field of research, and initial animal studies show that behavioral traits relevant in more than one context can sometimes be correlated. For example, guppies that will readily “inspect” a potential predator are more likely to be the dominant aggressors in a group of feeding guppies. And studies of zoo animals in multiple institutions have enabled some researchers to pinpoint specific exhibit or husbandry characteristics that affect animal temperament, social behavior, and stress.
Clouded leopards housed in enclosures with little vertical space and those whose keepers spend little time interacting with them have higher stress hormone levels, for example (Wielebnowski et al., 2002). The increased breeding success of black rhinos housed in bigger enclosures, and the heightened mortality of those housed in enclosures with a high degree of publicly accessible perimeter provide additional examples (Carlstead et al., 1999).
Assessing Temperament
The research team’s study, conducted at four facilities in China housing a total of 38 adult giant pandas, followed on these ideas. Their goal was to uncover any relationships between temperament, husbandry, housing, and the reproductive behavior of giant pandas.
To assess the temperament of the study animals, the researchers gave each panda an object it had not seen before (a large PVC pipe joint), and a scent it had not been exposed to before (anise or peppermint liquid extract applied on a brick). Responses to the object and scent, such as how long it took the panda to touch the object or how much time it spent interacting with the object, were then measured. Using these behavioral measures and a statistical test called principal components analysis, researchers were able to identify three personality traits dubbed SHY, EXPLORATORY, and ACTIVE that could account for the pandas’ responses during the test.
SHY is the sum of the amount of time it took the panda to approach the novel object and the novel scent. Higher SHY scores reflect timidity or fear of novel stimuli.
EXPLORATORY is the sum of the numbers of playful and passive visits to the object or scent during the test and reflects a tendency toward or interest in novel stimuli.
ACTIVE is the sum of the amount of time spent interacting or playing with the novel object or scent and thus reflects how manipulative, active, and playful the pandas are with novel objects.
The study showed that males and females did not differ significantly in these personality traits.
The next step was to determine how these traits were affected by giant panda husbandry and management, and how the traits correlated with reproductive behavior.
Shyness Hurts
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| Pandas whose keepers play with them tend to be more active. |
For both sexes, pandas with keepers who reported playing with them more frequently had higher ACTIVE scores, and pandas that spent more time indoors were actually less SHY than others. Shyness also tended to increase as the number of available dens decreased and the regularity of the husbandry routine decreased.
Females exhibiting frequent scent marking behavior had lower EXPLORATORY scores. And, the females reported as aggressive towards males during the breeding season were more SHY and less EXPLORATORY overall. Females demonstrating a lack of interest in some males during the breeding season were more SHY and demonstrated less scent marking and sexual behavior overall, but females that were allowed to occupy male enclosures before the breeding season were more ACTIVE and demonstrated more scent marking and sexual behavior.
The research results suggest that shy or timid females exhibited poorer reproductive behavior than bolder, confident females. In addition, females that showed less interest in novel objects were more likely to be aggressive towards males. Bolder females were less likely to be aggressive towards males during the breeding season however, and were more likely to show interest in the males with which they were paired.
The results also indicated that bolder males interested in novel objects may perform better during the breeding season. Males with high ACTIVE scores tended to attempt more social interaction with other pandas during the breeding season and to engage in more dirt bathing behavior (which may be related to olfactory communication). SHY males on the other hand tended to make fewer attempts at social interaction during the breeding season.
The research team also found that males with less environmental enrichment and those with keepers who spent less time playing with them, were more likely to be aggressive. Male aggression towards females is sometimes a problem during the breeding season.
These results indicate that there is a relationship between certain aspects of giant panda temperament and reproductive behavior during the breeding season. Shy animals often perform more poorly. In addition, the results show that temperament is affected by certain characteristics of management, husbandry, and exhibit features.
Taken together, this suggests that efforts to reduce shyness should be implemented in order to improve reproductive behavior and that changes in giant panda management, exhibition, and care could have a positive effect on reproductive behavior. Such efforts might include providing environmental enrichment, establishing comfortable relationships with keepers, providing more dens or refugia from the public, and taking measures to minimize stressful stimuli such as visitor noise.
Finally, the researchers determined that certain aspects of giant panda management have a direct impact on reproductive performance. For both sexes, it appears to be beneficial for giant pandas if keepers establish good relationships with the animals in their care and ensure that husbandry routines remain consistent enough not to cause stress.
The scientists also recommended that females be given ample opportunities to become familiar with potential mates long before the breeding season by swapping enclosures. Previous research showed that males benefit from enclosure swapping before the breeding season as well. However, the researchers caution that husbandry routines that become completely predictable may lead to trained responses in pandas and contribute to boredom.
For more information:
“Looking for Answers in China’s Breeding Centers”
References
Carlstead, K., J. Mellen, and D.G. Kleiman 1999. Black rhinoceros (Diceros bicornis) in U.S. Zoos: I. Individual behavior profiles and their relationship to breeding success. Zoo Biology 18:17-34
Wielebnowski, N.C., N. Fletchall, K. Carlstead, J.M. Busso, and J.L. Brown 2002. Non-invasive assessment of adrenal activity associated with husbandry and behavioral factors in the North America clouded leopard population. Zoo Biology 21:77-98.
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