Behavioural response and physiological adaptation of captive sub-adult giant pandas in response to a short-term social environment.

During ex-situ conservation, giant pandas inevitably transition from their natural wild habitats to captive environments. The living conditions of captive giant pandas differ significantly from those in the wild. For instance, during the sub-adult stage, solitary giant pandas are human-reared in groups. What impact does the captive social environment have on solitary giant pandas? Does it lead to changes in behavioral expression patterns? Is this pattern associated with physiological responses for environmental adaptation? To address these questions, we allocated six giant pandas into a group-housed group and a solitary-housed group, with each group consisting of three pandas. By observing their behaviors and performing analyses of urinary and fecal metabolomics, as well as metagenomics, we intended to explore the welfare status of the two groups under different management approaches. The results showed that group-housed sub-adult giant pandas exhibited significantly more playing behavior compared to those in solitary conditions. Further analysis revealed that the majority of the playing behavior involved playful interactions with companions. Additionally, we did not observe stereotyped behaviors in group-housed giant pandas. Through an exploration of the omics data, it was found that urinary metabolites associated with positive emotions, such as dopamine, along with related metabolic pathways like the dopamine synthesis system, were significantly upregulated and activated in group-housed giant pandas. Meanwhile, fecal metabolites associated with neurotransmitter synthesis and mood regulations, as well as the abundance of beneficial intestinal flora, were significantly higher in the feces of the group-housed pandas than those of the solitary-housed group. These findings indicated that short-term group housing does have an impact on the behavioral expression patterns of captive sub-adult giant pandas. Moreover, compared with those housed individually, short-term sub-adult giant pandas kept in groups seem to experience less stress. This reveals the behavioral response and physiological adaption of captive sub-adult giant pandas to group living environments.