Jetlag, or circadian arrhythmia in scientific jargon, is a phenomenon of desynchronisation that occurs particularly during long journeys.
But it doesn’t just affect globetrotters: captive pandas might also seem to suffer its effects, especially if they live far from their homelands.
Researchers at Scotland’s University of Stirling have studied the mechanics of the circadian clock – the cluster of cells that serve as the body’s master clock – in giant pandas. For good reason: this emblematic Chinese animal is known for its particularly slow pace.
This sluggishness is not only attributed to the animal’s diet, which consists almost exclusively of bamboo, but to factors linked to their lifestyle.
Giant pandas live mainly in zoos and reserves. A 2014 census estimated that only 1,864 specimens were living in the wild.
It is, therefore, possible that those in captivity have different circadian rhythms to those in the wild, since most of them live in latitudes other than those of their homelands.
To test this theory, the academics observed the behaviour of 11 giant pandas in six zoos over the course of a year. Every month, they focused their attention on a single animal for an entire day, to obtain unbiased information on the behaviour of all the pandas.
This research protocol, detailed in a paper published in the journal “Frontiers in Psychology”, highlights the fact that these animals have a highly seasonal lifestyle.
Overall, captive pandas showed three peaks of activity during the day, including one at night, just like their wild counterparts.
Those living in latitudes corresponding to those of China have a similar rhythm of life to that of their counterparts in the wild. They are, for example, more active in early spring, as this corresponds to a migration period for the species.
On the other hand, specimens living far from their native region are less active at this time of year. This could be explained by different light and temperature levels from their natural environment.
Giant pandas also differ in their sexual behaviour, whether in captivity or in the wild. Those living in zoos have attitudes that suggest they would like to procreate every three to four months, rather than just in spring, as is the case for those in the wild.
Furthermore, captive pandas react to signals that don’t exist in their natural habitat. They tend to be active very early in the morning, probably because they anticipate the visit of the keepers responsible for feeding them.
These observations show the extent to which the well-being and behaviour of pandas depend on their circadian clock.
“When giant pandas are housed at higher latitudes – meaning they experience more extreme seasons than they evolved with – this changes their levels of general activity and abnormal behaviour,” lead author Kristine Gandia explained.
It is, therefore, important that zoos take into account how these animals’ needs change cyclically over time to make their life in captivity easier – and to prevent them from being permanently “jetlagged”.