Survey of Transport Environments of Circus Tigers (Panthera Tigris)

Abstract

The type of equipment used to transport circus tigers, environmental factors experienced during transport, and resultant body temperatures of tigers transported were surveyed during hot and cold weather conditions with six different circus tiger acts. Dataloggers recorded interior and exterior temperatures, relative humidity, and radiant heat at 5-min intervals during each trip. Microdataloggers fed to the tigers recorded body temperature and were recovered from eight Bengal (Panthera tigris tigris), Siberian (P. t. altaica), or Bengal-Sumatran (P. t. tigris-P. t. sumatrae) cross tigers from four different circuses. Three basic types of systems were used by circus acts to transport tigers: freestanding cages mounted on wheels that were winched or pushed into a semitrailer for transport, cages built into the trailer itself, and weather-resistant units transported on flatbed railcars or flatbed truck trailers. The highest temperature encountered inside a trailer was 37.3 degrees C in hot weather conditions, but overall, temperatures were usually between 21.1-26.7 degrees C. Temperature inside the trailers did not appear to be affected by movement and did not generally exceed ambient temperatures, indicating adequate insulation and passive ventilation. During cold weather trips, the lowest temperature inside the trailers was -1.1 degrees C, occurring during an overnight stop. Interior temperatures during cold weather transport stayed 2-6 degrees C warmer than ambient temperatures. The body temperatures of the tigers were unaffected by extreme temperatures. The only changes observed in body temperature were increases of 1-2 degrees C caused by activity and excitement associated with loading in several groups of tigers, regardless of whether it was hot or cold weather. Whenever measured, carbon monoxide and ammonia were below the detectable concentrations of 10 and 1 ppm. respectively. Overall, transport did not appear to have any adverse effects on the tigers' ability to thermoregulate.

Diurnal Body Temperature and Rate of Passage of Loggers in Lions

“…Similarly to this study, Nevill et al [ 5 ] fed Thermochron temperature loggers that recorded body temperature at 5 min intervals to circus tigers. Those tigers were being transported between venues and the goal was to look for signs of hyperthermia or hypothermia during hot and cold conditions.…”

“…The feeding of Thermochron temperature loggers to performing lions and tigers was approved by the Texas A&M University Animal Care and Use Committee. The technique has been used in published [ 5 ] and many unpublished studies without any adverse effects on the subjects. Because the lions in this study were privately owned, the study was also approved by the owner of the subjects, their trainers and care givers, and their consulting veterinarians.…”

“…Although the Valeriu Family also had two tigers, only their lions were used in this study to reduce possible sources of variation if a combination of tigers and lions were used. Additionally, studies have been published using performing tigers in the USA [ 5 ]. Calibration and functioning of the loggers was checked by allowing the loggers to stabilize at room temperature and run for 30 min.…”

“…After initially feeding each of the subjects a single logger, two of the lions were fed a second logger in the hopes of getting an estimate of how closely the two loggers compared when traveling through the digestive system of a lion, and to increase our chances of finding at least one logger from those lions. From our prior research with tigers [ 5 ], we expected the Thermochrons to start being expelled the next morning when the cats became active and had a bowel movement. Finding the small expelled Thermochrons was particularly challenging because there was a large amount of bedding in the dens where the lions spent the night and the cats also had access to relatively large exercise pens starting at 08:00.…”

“…However, no body temperature data exist for lions that document their diurnal pattern in body temperature. Body temperatures were recorded overnight at 5 min intervals for tigers traveling with six different circus acts in North America [ 5 ], but activities, time of day, and time in transit varied too much for inferences regarding circadian rhythms to be made. Trethowan et al [ 6 ] used surgically implanted temperature loggers in free ranging African lions that recorded body temperature at 5 min intervals over extended periods, but those researchers used daily averages as the experimental unit.…”