Animals have to be transported to travel from one place to another. This transport can affect the behavior and the biological responses of the animal. Transport has been shown to increase the release of a stress hormone called cortisol. Zoos, while they are a good resource for preventing extinction of endangered species, have to transport animals to different zoos for breeding and to improve the quality of the zoo. However, because zoos are not the same environment as a typical wild environment, all of the impacts of living in zoos need to be understood. Certain aspects of zoos have been studied, but transportation’s effects on zoo animals has not been studied enough. Researchers were interested in the effects of transportation on previously transported (experienced) and inexperienced (never transported) tigers. Specifically, the researchers were interested in how transport affected behavior and cortisol in experienced and inexperienced tigers.
In order to learn about the effects of transport on behavior and cortisol, five tigers were selected: two tigers who had experienced transport at least two times before the study, and three tigers who had never experienced transport. Tigers were led into a cage and were driven to a shaded area. The shaded area was not near any other animals. After transport for 30 minutes, the tigers were released back to their original enclosure. Feces were collected from each tiger during transport and collected for 12 days after transport. With these feces, cortisol levels were measured.
Tigers were videotaped for an hour before transport, during transport, and for an hour after transport. Behaviors of the tigers were analyzed, including activity level, time spent pacing, pace rate (turns per minute), time spent investigating (sniffing transfer cage), and ear position. Respiration rate was also estimated by counting rib cage flex at 15 sec intervals.
All tigers laid down for at least five minutes immediately after transport and spent an average of 75% of the hour after transport laying down as well. However, all tigers did respond to transport in different ways. One experienced tiger spent the entire time standing, slowly pacing, or propping on the side of the cage during transport. The other experienced tiger alternated between standing, walking, and lying down. One of the naïve tigers paced 63% of the time, while another naïve tiger sat 73% of the time and the third naïve tiger laid down 63% of the time.
As for biological responses, during transport, the average respiration rate was ~169% above the baseline respiration rate, and 10 minutes after transport, the respiration rate was ~236% above baseline. The experienced group of tigers had an average respiration rate of around 166% above baseline during transport and approximately 195% above baseline after transport. However, the naïve tigers had an average respiration rate during transport of 230% and 394% following transport.
Finally, when looking at cortisol release, in naïve tigers, cortisol concentrations were significantly higher than baseline until day 9 to day 12 blocks. However, in experienced tigers, day 3 to day 6 was the only significant block.
This study emphasizes the importance of fully researching methods for animals in captivity. Zoos and transport are not a natural environment for animals, and these procedures can have negative impacts on animals. Animals need to habituate to many of these practices so they don’t have these negative responses. In order to help animals habituate to possible unpleasant environments, positive stimuli should be provided to counteract the negative effects of the environment and to possibly reduce stress from the environment.
This study showed that even short transport can affect the biological responses of a tiger for 9 to 12 days. This stress response being expressed for many days demonstrates that transport is an unpleasant environment for animals, and that habituation to the environment combined with positive stimuli when entering the environment should be done before animals are transported for long periods of time.
Citations:
Dembiec, D. P., Snider, R. J., & Zanella, A. J. (2004). The effects of transport stress on Tiger Physiology and behavior. Zoo Biology, 23(4), 335–346. https://doi.org/10.1002/zoo.20012
