Do opposites attract? Effects of personality matching in breeding pairs of captive giant pandas on reproductive success

Successful and cost-effective conservation breeding programs rely largely on animals doing what should come naturally: mate & reproduce. Behavioral management, especially that targeting mate compatibility and choice, will be important to achieve breeding goals efficiently. The endangered giant panda, Ailuropoda melanoleuca, was once notorious for its poor reproductive performance in captivity. Although the panda breeding program has experienced great improvement in recent years, we hypothesized that a better understanding of the role personality traits play in mating behavior could further improve reproductive performance. We used animal caretaker surveys and novel object tests to characterize pandas according to several personality traits—including exploratory, aggressiveness, excitability, fearfulness, and general activity—and tested how variation in these traits influenced mate compatibility and offspring production. Our findings indicate that specific combinations of personality traits showed better reproductive performance than others. Sometimes personality trait similarity enhanced reproduction and sometimes it impaired reproduction, depending on the trait. For example, Excitable males paired with Low-Excitable females had better reproductive outcomes, but pairs with Low-Fearful males regardless of the female's Fearfulness performed better. Males that were more Aggressive than their female partner were more likely to mate and produce cubs than when the female had a higher level of Aggressiveness than the male. Applying these results to breeding management strategies should result in higher reproductive rates and the production of more candidates for China's panda reintroduction program. These results highlight the potential importance of associative mating patterns based on personality for conservation breeding programs for a large number of other species.