Title Rewrite: Pandas in Captivity May Experience ‘Time Zone Disruption’ if Their Circadian Rhythms Misalign with Their Surroundings

All animals possess an intrinsic timekeeping mechanism known as the circadian clock, which synchronizes with environmental cues. However, animals held in captivity, such as those in zoos, often encounter drastically different environmental cues compared to their wild counterparts.

Given that the circadian clock profoundly influences an animal’s behavior and physiology, its impact on the well-being of captive populations of species at high risk of extinction, like giant pandas, is of paramount importance. Scientists embarked on a quest to unravel how the “jet lag” experienced by animals residing in latitudes foreign to their evolutionary history, and thus exposed to unfamiliar circadian cues, affects pandas.

Kristine Gandia, the lead author of the study published in Frontiers in Psychology and affiliated with the University of Stirling, remarked, “Animals, including humans, have developed rhythms to synchronize their internal state with the external environment. When internal clocks fall out of sync with external factors such as light and temperature, animals endure adverse consequences. In the case of humans, this can manifest as jet lag, metabolic disturbances, or seasonal affective disorder.”

Giant pandas, by virtue of their highly seasonal lifestyles, serve as an ideal species for investigating the impact of the circadian clock on their well-being and behavior. Pandas exhibit a preference for specific bamboo species and are particularly fond of new shoots, leading to seasonal migrations coinciding with the emergence of these shoots in spring. This migration season also corresponds to the breeding season, making it easier for pandas to find mates when they congregate around these nutritious shoots. Given the immense popularity of pandas, many zoos housing them have public webcams that allow continuous monitoring of their behavior.

Zoos also offer a unique opportunity to comprehend the significance of the circadian clock in animal well-being by relocating animals to latitudes outside their typical range, where fundamental cues such as daylight and temperature vary. These altered conditions can potentially induce a state akin to jet lag in animals, particularly if their circadian rhythms are heavily reliant on seasonality, as is the case with pandas. Additionally, animals in captivity may be influenced by anthropogenic cues, such as the regular visits of keepers.

Kristine Gandia and her team conducted extensive observations using webcams to monitor 11 giant pandas in six different zoos, some within and others outside the pandas’ native latitudinal range. Over the course of 12 months, they conducted hourly focal sampling sessions to gauge how pandas’ behavior fluctuated throughout the day and across the year. Thirteen observers participated in this effort, recording general activity levels, sexual behaviors, and any abnormal conduct.

The study revealed that daylight and temperature played pivotal roles in influencing pandas’ behavior, particularly when the environmental conditions matched those found in the pandas’ natural habitat in China. Captive pandas exhibited three distinct peaks of activity within a 24-hour period, including nocturnal activity, mirroring the behavior of their wild counterparts. Interestingly, adult pandas displayed sexual behaviors predominantly during daytime hours, which aligns with their potential mate-finding patterns in the wild.

Pandas placed in latitudes significantly different from their native range displayed reduced activity, possibly due to disparities in daylight and temperature cues. This correlation was supported by the observation that pandas at mismatched latitudes exhibited the most divergence in behavior compared to those at matched latitudes when subjected to varying daylight and temperature cues.

Furthermore, the study found that all pandas responded to cues unique to their respective zoos, becoming highly active in the early morning and exhibiting abnormal behaviors, which might signify anticipation of keepers delivering fresh food.

Notably, the study revealed a synchronization between abnormal and sexual behaviors among pandas. This correlation could indicate their frustration at not being able to engage in normal migration or mating behaviors. Pandas in latitudes not matching their natural range displayed fewer abnormal behaviors, likely due to differences in the cues governing sexual behaviors.

Kristine Gandia emphasized the need to expand this research by incorporating physiological indicators and assessing sexual hormones. Such measures could offer valuable insights into the environmental influences on the timing of reproductive events, potentially aiding the conservation efforts for this vulnerable species known for its challenging breeding.

Source: Frontiers

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