Bamboo part preference plays a critical role in influencing the nutrient utilization and gastrointestinal microbiota composition of captive giant pandas. However, the effects of bamboo part consumption on the nutrient digestibility and gut microbiome of geriatric giant pandas remain unknown. A total of 11 adult and 11 aged captive giant pandas were provided with bamboo shoots or bamboo leaves in the respective single-bamboo-part consumption period, and the nutrient digestibility and fecal microbiota of both adult and aged giant pandas in each period were evaluated. Bamboo shoot ingestion increased the crude protein digestibility and decreased the crude fiber digestibility of both age groups. The fecal microbiome of the bamboo shoot-fed giant pandas exhibited greater alpha diversity indices and significantly different beta diversity index than the bamboo leaf-fed counterparts regardless of age. Bamboo shoot feeding significantly changed the relative abundance of predominant taxa at both phylum and genus levels in adult and geriatric giant pandas. Bamboo shoot-enriched genera were positively correlated with crude protein digestibility and negatively correlated with crude fiber digestibility. Taken together, these results suggest that bamboo part consumption dominates over age in affecting the nutrient digestibility and gut microbiota composition of giant pandas.

The giant panda (Ailuropoda melanoleuca) is a vulnerable animal in China, and it is crucial to improve the reproduction efficiency of the giant panda. Mate preference is an important part of natural mating. We hypothesized that AGS metabolites differ according to their mate preference. In this study, we determined estrus-associated hormone levels in the urine of 19 female giant pandas. After confirming estrus via hormone levels and behavioral observation, we collected environmental biomarkers for metabolomics analysis. A total of 19 samples were divided to two groups according to the mating preference of female giant pandas. Metabolomics analysis by LC-MS/MS showed that a total of 115 differentially expressed metabolites were identified, including 97 upregulated metabolites and 18 downregulated metabolites. We found that prostaglandin B2, palmitoylcarnitine, prostaglandin G2, and estrone may be the potential markers of female mate preference. Pathway enrichment analysis showed that steroid hormone biosynthesis, phenylalanine metabolism, and tropane, piperidine, and pyridine alkaloid biosynthesis were the top three pathways. These results revealed the physiological changes in female giant pandas during mate preference trials, providing a perspective for understanding their chemical communication system reliant on anal gland secretions and improving the success rate of natural mating of giant pandas.

Neopterin is a well-characterized marker of cell-mediated immunity. Here, we used neopterin as a biomarker to identify the cellular immunity status of breeding giant pandas throughout gestation. Urine samples were collected from captive adult female giant pandas that had entered estrus and were either naturally bred and/or artificially inseminated (AI) during the breeding seasons at the Chengdu Research Base of Giant Panda Breeding. This study was divided into two parts. In the first part, we examined the urinary neopterin and progesterone (Pg) profiles during pregnancy in parturient and nonparturient individuals. From the day of mating to the Pg peak, there was no correlation between neopterin and Pg in both parturient individuals (n = 3) and nonparturient individuals (n = 3). During the period when the Pg dropped from its peak to approximately 100 ng/mg Cr, the changes in neopterin and Pg showed a negative correlation in parturient individuals, while there was no correlation between the changes in neopterin and Pg in nonparturient individuals. Subsequently, urine samples were categorized into four phases based on the reproductive status of giant pandas: (1) Estrus phase (Es); (2) Primary Pg increase phase (S1), during which Pg levels rise from the day of mating to 100 ng/mg Cr; (3) Secondary Pg increase phase (S2), during which Pg levels rise from 100 ng/mg Cr (inclusive) to their peak value; and (4) Post-peak Pg decline phase (S3), during which Pg levels decrease from their peak (inclusive) until they drop to approximately 200 ng/mg Cr. Analysis revealed that differences between parturient and nonparturient females emerged in the S3 phase. Compared to nonparturient individuals, neopterin concentrations showed sustained elevation in parturient pandas during the S3 phase. The second part of the study, building on the findings of the first part, specifically focused on analyzing the urine samples of giant pandas during the S2 and S3 phases. Statistical analysis of an expanded sample of individuals (including those from the first part) revealed a significant difference in the neopterin mean S3/S2 ratio between the parturient group (mean S3/S2 = 1.71 ± 0.12; n = 14) and the nonparturient group (mean S3/S2 = 0.85 ± 0.04; n = 17). Correspondingly, parturient individuals gave birth 5 to 16 days after the end of the S3 phase (this time corresponds to the point when Pg levels decrease to approximately 200 ng/mg Cr). The results revealed the validity and applicability of using the neopterin mean S3/S2 ratio (1.71 ± 0.12) for diagnosing successful pregnancy in mated female giant pandas.

Understanding how individual personality traits relate to stress and abnormal behaviors is essential for improving animal welfare and management. However, few studies have quantitatively examined these relationships in giant pandas. This study aimed to investigate how personality traits predict stereotypic behavior and physiological stress responses in captive giant pandas under a simulated transport context. Stereotypies are abnormal repetitive behaviors thought to reflect stress coping, and personality is increasingly recognized as a factor shaping animal welfare. We compared non-stereotypic (n = 16) and stereotypic (n = 16) giant pandas using keeper-based ratings, crate-entry training, and urinary cortisol. Intraclass correlation and principal component analyses identified two personality components, activity and timidity. Non-stereotypic pandas were significantly less timid (p = 0.005), whereas activity did not differ (p = 0.355). In crate-entry training, non-stereotypic pandas tended to enter faster (48.5 vs. 139.5 s; p = 0.074), and timidity was strongly correlated with latency (ρ = 0.74, p < 0.01). Censoring-aware analyses treating 300 s as right-censoring further supported this pattern (stratified Cox (Hazard Ratio) HR = 3.09, 95% CI 0.93–10.25; likelihood-ratio p = 0.052; log-normal accelerated failure-time model time ratio = 0.36, p = 0.054). Urinary cortisol showed no between-group difference after adjustment (geometric mean ratio = 0.93, 95% CI 0.57–1.49; p = 0.75), with consistent sensitivity analyses. These findings indicate that stereotypic pandas are more timid, and higher timidity predicts slower adjustment to a stress context, highlighting the value of personality assessment in management to mitigate stereotypies and improve welfare, while inconsistent cortisol results warrant further study.

The giant panda (Ailuropoda melanoleuca) is one of the animals with the largest body weight differences between its birth and adult stages, where the newborn cub is 0.1% the size of its mother. The rapid growth of panda cubs has been reported previously, but little is known about the growth pattern of their entire lifetime. In this study, we analyzed body weight records from 206 captive giant pandas collected between 2000 and 2022. The dataset comprised 26,340 measurements, including 12,314 records from 98 males and 14,026 from 108 females, with the oldest male and female being 32 and 37 years old, respectively. Utilizing machine learning, we predicted daily body weights throughout the pandas’ lifespan, allowing us to establish detailed daily normative body weight ranges from birth to advanced age. This study presents the first comprehensive analysis of lifetime body weight distribution in giant pandas, enhancing our understanding of their developmental biology and informing improved body weight management strategies for captive populations.

Environmental enrichment is commonly used in captive animal management, but the behavioural effects of specific enrichment devices are not always evaluated systematically. We conducted two experiments to evaluate three foraging-based feeding devices used with adult male giant pandas during summer indoor housing. In a repeated-presentation experiment with four pandas, responses to the devices were strongly individual-specific: three pandas interacted most with Device B and one with Device A, and interaction duration declined across repeated presentations in a non-uniform manner. In a complementary exploratory single-case (A–B) comparison with two pandas, feeding devices were associated with a marked within-individual reduction in abnormal behaviour (90.2% and 75.1%; Cliff’s delta = −0.83 in both) and a shift in behavioural events from locomotion toward exploration. These findings support evaluating feeding enrichment at the individual level in captive giant panda management.