Host Identity and Geographic Location Significantly Affect Gastrointestinal Microbial Richness and Diversity in Western Lowland Gorillas (Gorilla gorilla gorilla) under Human Care

The last few decades have seen an outpouring of gastrointestinal (GI) microbiome studies across diverse host species. Studies have ranged from assessments of GI microbial richness and diversity to classification of novel microbial lineages. Assessments of the “normal” state of the GI microbiome composition across multiple host species has gained increasing importance for distinguishing healthy versus diseased states. This study aimed to determine baselines and trends over time to establish “typical” patterns of GI microbial richness and diversity, as well as inter-individual variation, in three populations of western lowland gorillas (Gorilla gorilla gorilla) under human care at three zoological institutions in North America. Fecal samples were collected from 19 western lowland gorillas every two weeks for seven months (n = 248). Host identity and host institution significantly affected GI microbiome community composition (p < 0.05), although host identity had the most consistent and significant effect on richness (p = 0.03) and Shannon diversity (p = 0.004) across institutions. Significant changes in microbial abundance over time were observed only at Denver Zoo (p < 0.05). Our results suggest that individuality contributes to most of the observed GI microbiome variation in the study populations. Our results also showed no significant changes in any individual’s microbial richness or Shannon diversity during the 7-month study period. While some microbial taxa (Prevotella, Prevotellaceae and Ruminococcaceae) were detected in all gorillas at varying levels, determining individual baselines for microbial composition comparisons may be the most useful diagnostic tool for optimizing non-human primate health under human care.

Playing together, laughing together: Rapid facial mimicry and social sensitivity in lowland gorillas

In non-human animals, the phenomenon of Rapid Facial Mimicry (RFM) - the automatic, involuntary and rapid (&lt; 1 sec) replication of others’ facial expressions—has been mainly investigated in the playful domain. In immature lowland gorillas Gorilla gorilla gorilla both Play Face (PF) and Full Play Face (FPF) are rapidly mimicked between the players. This makes the species suitable to test hypotheses on the factors influencing RFM during play. The observations on three captive groups of lowland gorillas (N = 27) revealed that contrary to expectations, the closeness of social bond negatively influenced the occurrence of RFM but it did not affect either RFM latency or its overlapping index. RFM was affected by the degree of symmetry of play fighting: the more balanced the session, the higher the occurrence of RFM. Players of the same sex class responded faster than players of different sex. These findings suggest that RFM may help synchronizing behaviours of playmates matching in size (same-sex) and promote symmetric playful interactions. “Laughing together” (measured by the RFM overlapping index) lasted longer when the responder perfectly mirrored the partner expression (PF→PF; FPF→FPF). If PF and FPF convey information on the different play roughness degree, through “laughing together” the players could coordinate their actions and share positive moods and playful intensity. If the perfect congruency in the motor resonance, also known as social sensitivity, can foster a possible emotional dialogue between gorillas remains to be investigated.

How OBGYNs can assist in the prenatal care and delivery of western lowland gorillas

Prenatal care and perinatal planning are paramount for successful delivery outcomes in human pregnancies and has been shown to be equally as important with non-human primates. The authors describe two pregnancies and deliveries of a 12-year-old primigravid western lowland gorilla, Macy. Macy’s first pregnancy resulted in a stillbirth and was complicated by breech positioning, while her second pregnancy resulted in a viable infant. This case report outlines the prenatal care Macy received in her pregnancies and highlights the importance of ultrasound for dating and fetal evaluation. The authors discuss options for breech positioning and considerations for cesarean section. This article showcases how obstetricians and veterinarians can implement human obstetrical recommendations with non-human primates to improve delivery outcomes.