Does Training Affect Zoo Animal Behaviour?: A Case Study With Lemurs
Positive-reinforcement training (PRT) uses rewards to reinforce certain behaviors. In the case of animals in captivity, PRT is often used to get animals to comply with researchers, zookeepers, and other handlers. Previously there has not been much research done on how PRT affects the daily behavior and welfare of subjects outside of the training sessions. There is also a lack of research on the effects of training ring-tailed lemurs specifically, a species that is common in both zoos and laboratories. This study, published in the journal of Applied Animal Behavior Science, measures the effects of PRT on the day-to-day behavior of captive ring-tailed lemurs.
In this study, 11 ring-tailed lemurs living in captivity in Italy were taught to individually enter a training area to receive a food reward. The daily behavior of the lemurs was measured before any training was introduced (baseline period) and then again during the days in which the lemurs were trained to get the reward (training period). Certain behaviors were measured as a percentage of the time that the specific behavior was displayed out of the total time that the lemurs were observed. The averages of these percentages were then compared between the baseline and training periods.
The authors found that lemurs were out of sight significantly less often during the training period than during the initial baseline period (4.36% vs 15.46%). This may be a good sign for welfare: since lemurs tend to hide more when stressed, being visible more often could indicate less stress. It could also reflect an increased comfort with being seen by human observers, which has implications if the animals are in zoos. Additionally, the authors found an increase in the display of social behaviors during training compared to baseline (31.80% vs 12.52%), and a decrease in aggressive or hostile behaviors during training compared to baseline (0.07% vs 0.23%). These results indicate that PRT may lead to improved social relations between lemurs, which is good for their welfare. Finally, although lemurs displayed some stress-related behavior during training (likely because lemurs are highly social and, in order to get the reward, each had to stray away out of sight of the group), these stress-related behavior did not carry through to daily life.
Eventually all 11 lemurs learned to voluntarily isolate themselves to get the food reward. Since veterinary and research procedures often involve temporary isolation, teaching lemurs to voluntarily separate from the group is a valuable way to reduce stress for them. Additionally, the effects of PRT seemed to improve welfare overall in the case of the ring-tailed lemurs in this study. Consequently, the authors claim that “husbandry, veterinary care, research, and consequently the welfare of lemurs could be improved with this procedure.” Advocates can help urge facilities where captive lemurs are held to use PRT methods to improve the welfare and compliance of the animals, as a measure to improve their lives if they can’t be removed from labs altogether.[Contributed by Mona Zahir]