The Polar Bear Project

Polar bears are active, intelligent creatures. The Zoo staff and WCU researchers have been working together to continue developing environmental enrichment methods for these animals. A critical part of this project is the accumulation of data concerning how the bears spend their time, collected by students and volunteers observing the bears.

The polar bear enclosure at the Philadelphia Zoo.

Student observers tracking the bears

Accurate data collection required taking measurements inside the bear yard (when bears were elsewhere!).

Visual Discrimination

Although there are numerous conflicting anecdotal reports concerning polar bear vision, there was no scientific evidence concerning whether the bears have color vision. In a paper recently reported to the Animal Behavior Society, some members of our team used behavioral tests to establish that polar bears do indeed see in color. The experiment used a discrimination task, with ice blocks of different colors thrown into the enclosure in pairs. At any given time, one color reliably contained a food treat and the other color was empty. The bears were creative about retrieving the ice blocks, as shown in the photograph, in which Klondike is attempting to create a current to bring an ice block to her, rather than entering the water:

Some ice blocks are empty...	...and others contain food treats

The results were clear. The bears rapidly performed better than guessing would allow, and we had taken many steps to make sure that color was the only cue that would signal the right answer. When they had mastered the discrimination, we reversed the colors (the block that had contained food was now empty and vice versa), and this disrupted their performance. Not only does that support the idea that they were using color to make the choice, but it gave them a whole new problem to solve. Performance rapidly climbed back to high levels, as shown in the graph.

This approach also creates the potential to give the bears an ongoing series of problems to solve, providing increased stimulation. For example, when they reach proficiency with one pair of colors, the conditions can be reversed (the empty color now contains food, the "treat" color becomes empty), or new colors could be used.

While enrichment and problem-solving activities are happening, the data clearly show that the bears' activity levels increase. There is also evidence suggesting that the bears' behavior is changed more broadly. For at least two hours after a session of problem-solving trials, the bears are less likely to be asleep or out of sight, and they are more physically active. The evidence also shows increases in play behavior, examples of which are shown here.

The polar bear project is ongoing, experimenting with different behavioral enrichment techniques, trying to discover the bears' cognitive abilities, and studying the social interactions between the bears. If you would like to help with this type of research or contribute more generally to the animals, contact West Chester University or the Philadelphia Zoo.

Last updated: 6/30/1999
E-mail comments or questions to Dr. Michael J. Renner
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