It’s an established fact that compatibility is important to humans when picking a mate—but conservationists have discovered that Homo sapiens aren’t the only species where well-matched personalities may make or break a relationship. According to a study published in Biological Conservation, an international peer-reviewed journal in the discipline of conservation biology, personality traits may play a large part in the mating behaviors of the giant panda—and breeding successes or failures may depend on whether a bear’s disposition is complementary to that of its prospective mate. As part of the study, San Diego Zoo Global biologists used various assessments to test their theory, dividing the pandas into several personality categories based on their exploratory ability, aggressiveness, excitability, fearfulness and general activity. Then they tested how the differences in each of these traits influenced the willingness of the bears to mate with one another, and whether such parings produced offspring.