COLLEGE STATION If you were to ask Heath Nevill what he did on his summer vacation, he’d probably give you one of his quick smiles. And then he’d tell you that he spent his summer with the circus.
But not in the way you’d think. Nevill, who graduated in May from the department of animal science at Texas A&M University with a master’s degree, spent the last two summers traveling with several major circuses in Virginia, New York, California and Texas, watching every movement of tigers and digging through their feces for data loggers to collect physiological information.
Most people would consider this unnatural behavior. But for Nevill, a native of Beaumont, it was all part of his thesis. Under the tutelage of Texas A&M department of animal science professor Dr. Ted Friend, Nevill was studying circus tigers’ behavior and environment.
According to Nevill, circus tigers are among the most intensely managed and transported of all animals in captivity. There are at least 100 circuses in the United States that perform at least once a year, according to the Outdoor Amusement Business Association.
“Due to the necessity of transport in the circus industry, cages have to be kept small for efficiency,” Nevill said.
Even though tigers in the wild spend about 12 to14 hours of their day sleeping, he said, the other part of the time is spent hunting and patrolling their territory.
When they are in captivity, these activities are out. Many tigers in captivity “pace” their cages.
“I liken it to a person tapping their foot, you have to release that nervous energy,” Nevill said. “It’s not necessarily bad for their health, per se, especially in the cats where they’re just walking back and forth. But when you have them in a public setting, you don’t want them walking back and forth.”
Nevill and Friend theorized that providing a larger pen for exercise would decrease that stereotypical behavior. They also wanted to assess treatment of the animals during transport. He and Friend applied for and received a grant from the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service.
Nevill observed the tigers while on location. Some circuses, like Ringling Bros., Barnum and Bailey, already provide their tigers exercise pens approximately 25 feet (circular) that are attached to their smaller “home” cages. At other circuses, he observed them in their cages.
“Ideally, what you would expect is the more time they spent in the exercise pen, the less time they would spend pacing back in their home cage,” Heath said.
“Unfortunately, we didn’t get a statistical validation of that. What we did find was that for the tigers that covered the most area in the exercise pen, there was a strong inverse correlation between the amount of activity in the exercise pen and the amount of pacing they did once we put them back in their home cage. The more area the tiger was able to cover while it was in the exercise pen, the less it paced once it was back in its home cage.”
Even though tigers are solitary creatures in the wild, coming together only for mating, Nevill found there was much socializing among the tigers when in exercise pens. “Because they’re hand-raised in groups, their solitary nature gets replaced by wanting to be in a group. They will play together and interact. That’s a good source of stimulation,” Nevill said.
Transport is a weekly, if not daily, event for a circus. To study stress on the tigers when being moved from location to location, Nevill measured the body temperatures and external temperatures and humidity of six circuses and cat acts.
Data loggers about the size of a watch battery were placed into food and given to the tigers. When passed through the feces a few days later, the data loggers would yield a record of body temperatures at five-minute intervals. Other data loggers were placed inside trailers to record external temperatures, relative humidity and radiant heat at five-minute intervals during the day.
What the researchers found was that the maximum temperature encountered inside a trailer was 98.6 degrees F in hot weather conditions, but generally stayed between 68 degrees and 80.6 degrees F. The temperature inside the trailers did not appear to be affected by movement and did not exceed ambient (surrounding) temperatures, indicating the trailers were adequately insulated and ventilated.
During cold weather trips, the lowest temperature inside the trailers was approximately 27 degrees, which occurred when the door had to be opened for loading. The interior temperatures during cold weather stayed one or two degrees warmer than the ambient temperatures during transport.
“The corresponding body temperatures of the tigers were unaffected by even the most extreme temperatures,” Nevill said.
Tigers and lions are naturally adapted to a wide range of environmental conditions. Bengal and Sumatran tiger subspecies thrive in the hot and humid rainforests of India and Indochina where temperatures can exceed 98 degrees F with 100 percent humidity. On the other hand, Bengal tigers have been found at elevations of 3,000 feet in the snowy, coniferous forests of the Himalayas.
In the Texas A&M study, “The only changes observed in body temperature were increases of one or two degrees caused by activity and excitement associated with loading and transport in several groups of tigers, whether it was hot or cold.”
Also, carbon monoxide and ammonia were always below detectable concentrations.
“Overall, transport did not appear to have any adverse effects,” Nevill said.
By putting cameras into the trucks when the tigers were being moved, Nevill and Friend found they will both stand up and lie down in transit.
“Horses and cattle generally stand up, pigs almost always lie down,” during transport, Friend said.
“Different animals have different ways of coping. Cats are pretty flexible,” he said.
What actually elicits pacing in tigers is the subject of future study, Friend said. It’s not known for sure if it is the lack of hunting or patrolling, or whether it could be outside stimulation, anticipation of being fed or watered, or looking forward to a performance.
From his own studies of elephants, Friend found the animals began rocking and weaving, another stereotypical behavior of animals in captivity, before performances. They also began rocking and weaving before being fed and watered.
“So it makes you wonder, Well, gee, maybe performances aren’t terrible, maybe they’re thinking of them in the same context as they think of food and water, something they like to do.’
“In the case of elephants, if you held them out of performances, they often try to go in the tent and perform. If you kept them outside in the pens, they would do their act, they would trumpet and try to get loose and go into the ring. If you think something nasty is going to happen to you, you don’t jump up and down in anticipation of it. You slink over to a corner and you’re quiet,” Friend said.
For more general information about tigers, Nevill recommended http://5tigers.org