Stereotypic behaviour predicts reproductive performance and litter sex ratio in giant pandas

Natural mating ability is associated with gut microbiota composition and function in captive male giant pandas

The issue of poor sexual performance of some male giant pandas seriously impairs the growth and the genetic diversity of the captive population, yet there is still no clear understanding of the cause of the loss of this ability and its underlying mechanism. In this study, we analyzed the gut microbiota and its function in 72 fecal samples obtained from 20 captive male giant pandas, with an equal allocation between individuals capable and incapable of natural mating. Additionally, we investigated fecal hormone levels and behavioral differences between the two groups. A correlation analysis was then conducted among these factors to explore the influencing factors of their natural mating ability. The results showed significant differences in the composition of gut microbiota between the two groups of male pandas. The capable group had significantly higher abundance of Clostridium sensu stricto 1 (p adjusted = .0021, GLMM), which was positively correlated with fatty acid degradation and two-component system functions (Spearman, p adjusted < .05). Additionally, the capable group showed higher gene abundance in gut microbiota function including purine and pyrimidine metabolism and galactose metabolism, as well as pathways related to biological processes such as ribosome and homologous recombination (DEseq2, p adjusted < .05). We found no significant differences in fecal cortisol and testosterone levels between the two groups, and no difference was found in their behavior either. Our study provides a theoretical and practical basis for further studying the behavioral degradation mechanisms of giant pandas and other endangered mammal species.

Parental effects on offspring sex ratio in the Numbat (Myrmecobius fasciatus): does captivity influence paternal sex allocation?

Sex allocation theories predict that under different ecological conditions the production of sons and daughters will affect parental fitness differently. Skewed offspring sex ratios often occur under captive conditions where individuals are exposed to nutritional and social conditions that differ from nature. Here, we analyzed 29 years of offspring sex ratio data from a captive population of an endangered marsupial, the Numbat (Myrmecobius fasciatus). We partitioned variation in offspring sex ratio based on parental origin (captive- vs. wild-bred), parental weight, maternal age, and maternal reproductive history. Our analyses revealed no effect of parental weight or maternal origin on offspring sex ratio-however, there was a significant effect of paternal origin. Data visualization indicated that captive-bred males tended to produce male-biased litters. We discuss the result in relation to recent studies that have shown that male mammals have the capacity to be arbiters of sex allocation and highlight candidate mechanisms, but consider it with caution due to the small sample size from which the result was derived. We performed a population viability analysis (PVA) to explore the potential impact of a sex ratio skew on the sustainability of the captive Numbat population under hypothetical scenarios. Our PVA revealed that supplementation with wild individuals is critical to the persistence of the captive Numbat population and that a biased sex ratio will lead to extinction of the captive colony under certain conditions. Overall, our study demonstrates that covert sex ratio skews can persist undetected in captive populations, which have the potential to become impactful and compromise population sustainability under changed management processes.

Latitudinal and zoo specific zeitgebers influence circadian and circannual rhythmicity of behavior in captive giant pandas (Ailuropoda melanoleuca)

Introduction

The circadian clock influences many aspects of animal welfare including metabolism, breeding, and behavior. In most species, circadian clocks are internal clocks regulated by external environmental cues called zeitgebers. The most common zeitgebers are light/dark cycles, food, and temperature. However, within captive environments, animals can be housed at latitudes with different light/dark cycles than their natural habitat and most other zeitgebers are controlled by humans. The effects that modified zeitgebers have on captive animals' circadian and circannual rhythmicity is largely unknown. To explore this and potential welfare implications, we measured and analyzed observational behavioral data of zoo-housed giant pandas for one year utilizing live camera footage from six zoos across the world. The worldwide distribution of the zoos gives us the unique opportunity to investigate how housing giant pandas within and outside of their natural latitudinal range can affect circadian rhythmicity and behavior.

Methods

Focal sampling was completed for 11 giant pandas each month for 12 consecutive months to gain an estimate of one circannual cycle. Within each month, we estimated one daylight or 24 h cycle of activity/behavior by conducting 10-min observation sessions systemically each hour the pandas were visible.

Results

Zero-inflated negative binomial mixture models found that latitude is associated with activity levels, with pandas housed outside of their natural latitudinal range displaying less activity than those within their latitudinal range. Amount of daylight, temperature minimum, and temperature range were also associated with activity cycles, potentially acting as zeitgebers. An association between sexual-related and stereotypic behavioral cycles was found, with the circannual cycles fluctuating in synchrony throughout several points in a year.

Discussion

These results indicate that changes to common zeitgebers and environmental conditions can influence circadian and circannual cycles. The widespread evolution of circadian rhythms suggests an adaptive advantage to possessing one in an environment with cyclical changes, allowing species to anticipate changes in their environment and respond accordingly. Therefore, although animals are highly adaptive, creating a captive environment that mimics the environmental conditions for which the animal has evolved can encourage naturalistic cycles that ultimately aid in promoting positive welfare states and increasing chances of successful breeding and conservation.

Understanding Circadian and Circannual Behavioral Cycles of Captive Giant Pandas (Ailuropoda melanoleuca) Can Help to Promote Good Welfare

Circadian and circannual cycles of behavior regulate many aspects of welfare including metabolism, breeding, and behavioral interactions. In this study, we aim to demonstrate how systematically determining circadian and circannual cycles can provide insight into animals' needs and be part of an evidence-based approach to welfare assessment. We measured and analyzed the observational behavioral data of 13 zoo-housed giant pandas (Ailuropoda melanoleuca), across life stages and between sexes, each month for one year using live camera footage from six zoos across the world. Our results indicate that life stage was associated with changes in overall activity, feeding, locomotion, and pacing, and that sex influenced scent anointing and anogenital rubbing. Overall, the circadian rhythms showed three peaks of activity, including a nocturnal peak, as seen in wild giant pandas. We also found associations between sexual-related, stereotypical/abnormal, and feeding behavior, which are possibly linked to the timing of migration of wild pandas, and elucidated the relationship between a mother and cub, finding that they concentrate maternal behaviors to mainly after closing hours. Understanding these cycle patterns can aid animal care staff in predicting changing needs throughout the day, year, and life cycle and preemptively provide for those needs to best avoid welfare concerns.

About pace: How variations in method and definition affect quantification of pacing in bears?

Repetitive pacing behavior is exhibited by many species in zoos and is particularly prevalent in carnivores with large home ranges, such as bears. Pacing can be a behavioral indicator of poor welfare, however, understanding this behavior can be challenging. As many bears that pace are singly housed, efforts to systematically examine and ameliorate pacing may be strengthened by multi-institutional studies. However, there is currently no standardized method to quantify pacing, which makes cross-institutional analyses of causal factors and intervening measures challenging. The purpose of this study was to compare multiple sampling methods and definitions for quantifying pacing in bears to understand how they affect outcome measures. We analyzed video recordings of two grizzly and two black bears pacing, using three sampling methods (continuous, instantaneous 30-s interval, instantaneous 1-min interval), and three definitions of pacing (AB-two repetitions of the path, ABA-three repetitions, ABAB-four repetitions). A generalized linear mixed model revealed that continuous and instantaneous 30-s interval methods captured more pacing than instantaneous 1-min methods, and definitions captured a decreasing amount of pacing from AB to ABA to ABAB. AB also captured the highest number of pacing bouts. The importance of comparability across institutions is growing, and a standard methodology and definition for recording pacing would be useful. We suggest that the combination of instantaneous sampling and the ABA definition presents a good balance between capturing the right data and being flexible enough for a variety of institutions to implement.

The Chemical Ecology of Elephants: 21st Century Additions to Our Understanding and Future Outlooks

Chemical signals are the oldest and most ubiquitous means of mediating intra- and interspecific interactions. The three extant species of elephants, the Asian elephant and the two African species, savanna and forest share sociobiological patterns in which chemical signals play a vital role. Elephants emit secretions and excretions and display behaviors that reveal the importance of odors in their interactions. In this review, we begin with a brief introduction of research in elephant chemical ecology leading up to the 21st century, and then we summarize the body of work that has built upon it and occurred in the last c. 20 years. The 21st century has expanded our understanding on elephant chemical ecology, revealing their use of odors to detect potential threats and make dietary choices. Furthermore, complementary in situ and ex situ studies have allowed the careful observations of captive elephants to be extended to fieldwork involving their wild counterparts. While important advances have been made in the 21st century, further work should investigate the roles of chemical signaling in elephants and how these signals interact with other sensory modalities. All three elephant species are threatened with extinction, and we suggest that chemical ecology can be applied for targeted conservation efforts.

Animal Personality and Conservation: Basics for Inspiring New Research

Simple Summary

The study of animal personality is important to conserve animals because it can help in selecting the most appropriate individuals to be released into the wild. Individuals not so bold or aggressive, less stressed, who explore their new environment with greater caution are often more likely to survive after release into the wild. In contrast, bolder and more aggressive animals reproduce more successfully and, therefore, can be released with the aim of rapid repopulation of an area. These and other aspects of how animal personality can help in conservation programs, as well as how to collect personality data are covered in this paper.

Abstract

The number of animal species threatened with extinction are increasing every year, and biologists are conducting animal translocations, as one strategy, to try to mitigate this situation. Furthermore, researchers are evaluating methods to increase translocation success, and one area that shows promise is the study of animal personality. Animal personality can be defined as behavioral and physiological differences between individuals of the same species, which are stable in time and across different contexts. In the present paper, we discuss how animal personality can increase the success of translocation, as well as in the management of animals intended for translocation by evaluating personality characteristics of the individuals. Studies of the influence of birthplace, parental behavior, stress resilience, and risk assessment can be important to select the most appropriate individuals to be released. Finally, we explain the two methods used to gather personality data.

Effects of Different Nursing Methods on the Behavioral Response of Adult Captive Giant Pandas (Ailuropoda melanoleuca)

Simple Summary

Throughout the life history of giant pandas, we have found that captive and wild giant pandas have significantly different parenting experiences. To summarize the breeding history of the Chengdu Research Base of Giant Panda Breeding over the past 30 years, we found that the parenting experience is related to the natural mating ability of captive male giant pandas. However, there are few studies on the effects of different nursing methods on the behavioral expression of captive giant pandas, mainly focusing on the behavioral development of captive giant panda cubs, but the effects on the behavioral adaptive expression and stress of adult females have not been reported. From the perspective of adult female giant pandas in the nursery period, this experiment attempts to clarify whether different nursing methods in the cub-rearing period will affect the behavioral adaptive expression of the dams. We aim to understand whether confinement mode may cause stress problems in adult captive giant pandas, and provide a scientific basis for improving the design parameters of nursery pens and improving the welfare level of captive giant pandas. Based on the current results, we find that, in the current captive environment, singleton and parent rearing are kinds of nursing methods that are in accordance with the characteristics of the natural nursing of giant pandas and have little effect on the mother–cub relationship and welfare of captive adult female giant pandas.

Abstracts

Nursing protocols in giant panda conservation breeding programs often strongly deviate from the natural cub-rearing behaviors observed in situ, potentially affecting the expression of species-typical behavior in both dams and cubs. To evaluate the effects of different nursing methods on the behavioral expression of captive adult female giant pandas, it is necessary to understand such effects due to unnatural human interference to improve the welfare of giant pandas in captive breeding conditions. In this study, we selected nine captive adult female giant pandas managed with different nursing methods as the research objects. Behavioral observations were performed during the early nursing period (1–90 d). Compared with the artificially assisted nursing method, captive adult female giant pandas who adopted the singleton and parent nursing method exhibited a significantly longer time engaged in mother–cub interaction behavior and invested a significantly smaller portion of their daily time budget on pacing and railing-directed behavior in the three months postpartum. However, no significant differences in the percentage of time exhibiting maternal behaviors were noted between the different nursing methods. In conclusion, in the current captive environment, singleton and parent rearing was a kind of nursing method that matched natural cub-rearing characteristics and was less stressful for captive adult giant pandas.