Research on the Foraging Strategies and Perceptual and Cognitive Abilities of the Giant Panda
Optimal foraging theory postulates that animals use efficient foraging strategies when searching for and processing food. Efficient strategies are those that maximize the energetic gains and minimize the energetic costs of foraging. One of the goals of research on optimal foraging theory is to determine what type of information a forager uses to make decisions such as where to forage, when to forage, which food items to consume and how long to stay in a particular food site. In locating sources of food, animals can use vision, olfaction, spatial memory, or any combination of these cues. Giant pandas have many morphological, physiological and behavioral adaptations that presumably help them increase their foraging efficiency on a low-quality food source like bamboo. However, it is unknown what role perceptual/cognitive abilities may play in giant panda foraging. This study examined the foraging strategies used by the giant pandas in a variety of foraging tasks with the goal of determining the type of information pandas use to make foraging decisions.
This study involved collaboration among Zoo Atlanta, Zoological Society of San Diego (ZSSD), and Smithsonian’s National Zoological Park (SNZP). Pandas from all three institutions were subjects. Seven pandas (3 males, 4 females) were included. The study was divided into six foraging tasks: exploratory, spatial, spatial reversal, visual, olfactory and search-research. The giant pandas at all three institutions started the study with the exploratory foraging task. However, we randomized the order in which we tested the pandas on the spatial memory, visual and olfactory tasks to control for carryover effects that can occur in studies of learning and memory.
The subjects at all three institutions performed similarly on the tasks. In the exploratory task, all pandas revisited previously depleted feeders more often in the first five sessions of the study than in the last five sessions. Therefore, all of the pandas learned to forage more efficiently over time with exposure to the task. Five of the seven giant pandas tested on the spatial memory task learned to visit only the four baited feeders within 20 test sessions. Reversing the baited feeders disrupted performance, indicating that the subjects were not using visual or olfactory cues. None of the pandas tested on the olfactory or visual phases learned the task. However, when we conducted a final foraging task to examine the relative importance of visual, olfactory or spatial cues for foraging, the pandas surprisingly preferred to rely on the visual cue to locate baited food sites. Their first two visits were more often to feeders with the visual cue than would be predicted by chance. In the first visual cue task, the location of the feeders with the visual cue changed randomly each day. However, in the final task there were several days of training in which the visual cue, olfactory cue and spatial cue were paired with each other. It is possible that the pairing of the visual cue with the spatial cues in the training trials facilitated learning. More research is necessary to determine if this explanation is correct.
None of the subjects tested learned to use visual or olfactory cues to find food when the location of baited feeders was randomly determined, suggesting that visual and olfactory cues are not important for foraging in the wild. However, most of the pandas were able to use spatial cues alone to locate hidden food. Furthermore, the pandas did not learn the position of the baited feeders in the reversal phase as quickly as they had learned the position in the spatial phase, suggesting that once they have learned the location of food they have difficulty adjusting their behavior and learning new locations. Therefore, pandas may not readily adapt to sudden changes in their environment.