Veterinary/zoology session

Environmental enrichment opens enhanced behavioural opportunities and therefore improves welfare of captive animals through modifications of their environment. Considering all aspects of the environment, enrichment can be categorised into 5 main groups: food, sensory, cognitive, physical and social. In constrained space the lack of physical activity is a frequent problem, which can lead to obesity, dysfunctional development and behaviour and to abnormal stereotypies. In spite of this fact, relatively few methods are available to increase the locomotor activity of animals.

The purpose of my work was to create or modify methods which can enhance locomotor activity of zoo gorillas indoors and outdoors.

In order to enrich the gorillas’ indoor holding area, I applied a previously tested method which may raise the animals' activity by placing honey onto the bark of the trees. During the ten honey-day - control-day pair repetitions I monitored the horizontal and vertical movements of the animals for 2.5 hours following the honey teatment. The analysis by linear model suggests that such treatment significantly increases the gorillas' horizontal movement by 9% on average, and their vertical movement by 52%.

In order to enrich the outdoor exhibit, we developed a programmable food-scattering machine which projects nuts into the enclosure at random time intervals to random locations, thus lowering the predictability of the food items in space and time. During seven repetitions of control and treatment days, I monitored the animals' horizontal movements for an hour with or without treatment. Statistical analysis applying linear model revealed that the treatment increased the gorillas' horizontal locomotion significantly by 81%.

My results suggest, that both methods are suitable to increase the gorillas' locomotor activity. I plan to test the effects of such enrichment methods on other species kept at the zoo in the future.