All animals have an internal clock, called a circadian rhythm, that helps the body know when to perform key functions like sleeping and eating. Circadian rhythms are dictated by cues in the environment like the timing of sunrise and sunset and changes in the environment can change how the animal functions.
For example, if you have ever traveled across time zones, you can experience jet lag. This happens when your body is on one schedule but the environment is sending different cues. When it is 2 am in one place (and you should be sleeping) your body might think it is 6 pm and you should be eating dinner. This disconnect between the environment your body is used to, like when meals timeless are, and the new environment it is exposed to causes changes in your behavior. New research from the University of Stirling in the United Kingdom showed that this happens in zoo animals too the Giant Panda. Moving animals away from their natural habitats is disruptive to their natural rhythm and they can experience jet lag just like humans do when traveling across time zones.
Wild giant pandas live in the mountains of China, but approximately 30% of all pandas globally are in zoos, many of which are at different latitudes than the panda’s native range. The latitudinal difference means the sun rises and sets at different times, which could impact the pandas’ circadian rhythm.
Like many wild animals, giant pandas change their behavior seasonally. They follow the emergence of new bamboo shoots in the early spring, and the excess energy from the nutritious young plants fuels the pandas into mating season. Captive pandas do not experience this yearly migration, which may disrupt their natural circadian rhythm. This difference may explain why captive breeding programs for pandas are rarely successful
Due to their popularity with the public, many zoos use webcams to monitor panda behavior around the clock. Doing so allows researchers to easily study panda behavior in zoos and understand the alterations in their circadian rhythm.
For one year, Kristine Gandia and her collaborators used zoo webcams to monitor the daily behavior of 11 giant pandas at 5 zoos: two at a similar latitude to the panda’s native range and three outside the latitudinal range. The observations included positive behavior like play and foraging, negative behavior like pacing, and social interactions between pandas.
The scientists discovered that daylight and temperature were important behavioral cues for pandas: both variables that vary by latitude. When the pandas were in zoos at similar latitudes to their native range, they exhibited similar behaviors to those in the wild. Furthermore, the adult pandas indicated they were available to mate only during the daytime, a behavior that might make it easier to find mates in the wild.
Pandas at zoos outside their native latitudes exhibited different behaviors. These pandas were less active likely due to the differences in daylight and temperature cues, as higher latitudes have more extreme differences between seasons than the weather patterns the species is used to.
However, even the pandas at the same latitude as their wild counterparts showed varied behavior due to zoo-specific cues. For example, the pandas were very active in the morning, unusual for wild pandas, likely in anticipation of a zookeeper visit with fresh bamboo.
Alterations in the circadian rhythm likely impact other animals too. Life at new latitudes may have significant impacts on the welfare of animals in zoos. The researchers suggest a variety of ways to assess changes in circadian rhythms in zoos, such as monitoring the behavior of animals over time and using such behavioral data to design exclosures and feeding schedules to match the natural circadian rhythm. Disruptions in circadian rhythm have impacts beyond the scope of individual animals experiencing a mismatch in meal and mating times. Changes in animal behavior in zoos can impact many of the zoo conservation programs which depend on breeding animals in zoos and learning how best to conserve animals in the wild. Learning to combat jet lag is not only a skill important for us as we switch time zones or cope with daylight savings, but it is also important for zoo animals to learn to cope with a new environment and achieve zoo conservation goals.
Citation: Gandia KM, Kessler SE and Buchanan-Smith HM (2023) Latitudinal and zoo-specific zeitgebers influence circadian and circannual rhythmicity of behavior in captive giant pandas (Ailuropoda melanoleuca). Front. Psychol. 14:1188566. doi: 10.3389/fpsyg.2023.1188566