DOES ENVIRONMENTAL ENRICHMENT REDUCE STEREOTYPIC BEHAVIOURS IN CAPTIVE BROWN BEARS?

Photo: M. Clark

Common stereotypic behaviours (stereotypies) in zoo animals include repetitive pacing and head rolling. Stereotypies are a particular problem with keeping large and intelligent animals in captivity.  

Zoo staff continually strive to improve the enclosures of captive animals and so stimulate the animals to perform natural behaviours and reduce stereotypies.

Ms Miranda Clark and Dr Ian Bland from the University of Melbourne investigated whether adding more features to Melbourne Zoo's Syrian Brown Bear (Ursus arctos syriacus) enclosure improved the two Brown Bear's welfare and quality of life.

In late April/May 2009, Zoos Victoria enriched the Brown Bear enclosure at Melbourne Zoo by:

• Deepening the water in the existing swimming hole, and adding a small wading pool and waterfall.
• Adding live fish to the pools to encourage fishing behaviours.
• Adding logs on the edge of the water.
• Adding platforms for shade and climbing.
• Deepening the mulch pit and adding another mulch pit for foraging.
• Planting pine trees and small plants.
• Adding a log bridge and seesaw.

The keepers also provide the Brown Bears with variable enrichment activities such as barrels and tyres containing food.

METHODS

The researchers documented the Brown Bears' behaviour over three ten-day periods. During each period they recorded the Brown Bears' behaviour every 60 seconds for two separate hours a day.

• Period 1 (April 2009) - Brown Bears observed in original enclosure
• Period 2 (May 2009) - Brown Bears observed immediately after release into their modified enclosure.
• Period 3 (September 2009) - Brown Bears observed after they had had time to habituate (get used to the modified enclosure).

RESULTS

Both Brown Bears only performed stereotypies when they were moving around the enclosure.  As expected for animals that hibernate in the wild, their activity levels decreased in winter (Period 2) and were highest in spring (Period 3). The female Brown Bear, Honey, consistently performed more stereotypies (50.5 - 58.1% of 'active' time) than the male Brown Bear, Roan (13 - 25.7% of 'active' time).

In Periods 2 & 3, both Honey & Roan used the new climbing structures, foraging pits and wading pool, and did not perform stereotypies while using these new structures.

The time spent on stereotypies was very variable.  In any given hour, the Brown Bears tended to not perform many stereotypies, but they occasionally spent long periods on stereotypic behaviours.  The median amount of time each Brown Bear spent performing stereotypies decreased from 5 min/hour (Honey) and 1.5 min/hour (Roan) during Period 1 to zero for both bears during Period 2. The median amount of time Honey performed stereotypies then increased in Period 3 to 13.5 min/hour, while the median time Roan spent on stereotypies remained at zero.

CONCLUSIONS

Unfortunately, modifying the Brown Bears' environment did not totally eliminate stereotypies. Because of the small sample size and seasonal differences between periods, it is difficult to say whether the changes to the enclosure affected the behaviour of Honey & Roan.  Other potential causes of behavioural change include pre-hibernation behaviour, changes in water temperature, and changes to keeping routines.

In Period 2 (and Period 3 for Roan), the Brown Bears performed stereotypies in less hours on less days.  Stereotypic behaviours were most common when the Brown Bears were anticipating being fed or being restricted from accessing the off-limits area. Stereotypies were also prevalent in stressful or frustrating situations.

To some extent, modifying the Brown Bears' environment (together with other enrichments) reduced the frequency of stereotypies.  However, further modifications and enrichment may be required.

FOR MORE INFORMATION

- on animal enrichment at Zoos Victoria - click here.