Wild Lowland Gorillas Research Articles

Same Space, Different Species: The Influence of Exhibit Design on the Expression of Zoo-Housed Apes’ Species-Typical Retiring Behaviors

Wild chimpanzees frequently make arboreal nests, while wild lowland gorillas typically nest on the ground. We aimed to understand whether zoo-housed apes' use of elevated spaces for retiring similarly differed between species and across exhibits. Using a pre-planned exhibit switch at Lincoln Park Zoo (Chicago, USA), we compared where (elevated or terrestrial) two groups of apes (Pan troglodytes and Gorilla gorilla gorilla) performed retiring behaviors (inactive, sleeping, and nest-building behaviors). We studied a group of six chimpanzees and a group of four gorillas in two exhibits of similar size and configuration for two three-month periods (between 3 and 5 p.m.) before and after the groups switched exhibits. We predicted that chimpanzees would be more likely to retire in elevated locations compared to gorillas, irrespective of the exhibit. We found a significant effect of exhibit on where the apes retired but no effect of species, such that both species were more likely to retire in elevated locations in one exhibit but not the other. This suggests that the specific characteristics of the exhibits (e.g., number of visual barriers) influenced the expression of the apes' retiring behaviors. These findings offer further insight in how exhibit design can influence the expression of natural behaviors in these species.

Gut microbiome composition and metabolomic profiles of wild western lowland gorillas (Gorilla gorilla gorilla) reflect host ecology.

The metabolic activities of gut microbes significantly influence host physiology; thus, characterizing the forces that modulate this micro-ecosystem is key to understanding mammalian biology and fitness. To investigate the gut microbiome of wild primates and determine how these microbial communities respond to the host's external environment, we characterized faecal bacterial communities and, for the first time, gut metabolomes of four wild lowland gorilla groups in the Dzanga-Sangha Protected Areas, Central African Republic. Results show that geographical range may be an important modulator of the gut microbiomes and metabolomes of these gorilla groups. Distinctions seemed to relate to feeding behaviour, implying energy harvest through increased fruit consumption or fermentation of highly fibrous foods. These observations were supported by differential abundance of metabolites and bacterial taxa associated with the metabolism of cellulose, phenolics, organic acids, simple sugars, lipids and sterols between gorillas occupying different geographical ranges. Additionally, the gut microbiomes of a gorilla group under increased anthropogenic pressure could always be distinguished from that of all other groups. By characterizing the interplay between environment, behaviour, diet and symbiotic gut microbes, we present an alternative perspective on primate ecology and on the forces that shape the gut microbiomes of wild primates from an evolutionary context.

Bifidobacterium moukalabense sp. nov., isolated from the faeces of wild west lowland gorilla (Gorilla gorilla gorilla)

Gram-staining-positive anaerobic rods were isolated from the faeces of a wild lowland gorilla (Gorilla gorilla gorilla) in Moukalaba-Doudou National Park, Gabon, and strain GG01(T) was taxonomically investigated. Based on phylogenetic analyses and specific phenotypic characteristics, the strain belonged to the genus Bifidobacterium. Phylogenetic analysis of its 16S rRNA gene sequence revealed that strain GG01(T) formed a single monophyletic cluster and had a distinct line of descent. Based on 16S rRNA gene sequence similarity, the type strains of Bifidobacterium catenulatum JCM 1194(T) (98.3%) and Bifidobacterium pseudocatenulatum (98.1%) JCM 1200(T) were the most closely related to this novel strain, although it was clear that they belonged to different species. hsp60 sequences also supported these relationships. The DNA G+C content of this novel strain was 60.1 mol%. Bifidobacterium moukalabense sp. nov. (type strain GG01(T) = JCM 18751(T) = DSM 27321(T)) is proposed.

Possible osteomyelitis of skull causes death of a wild lowland gorilla in the Lopé Reserve, Gabon

The remains of a juvenile gorilla, apparently dead for 3-4 days, were found in the Lopé Reserve, Gabon. The skull was recovered and showed a chronic lesion involving the insertion of the masseter muscle, consistent with chronic osteomyelitis.

Entodiniomorphid ciliates from the wild lowland gorilla with the description of a new genus and three new species

The entodiniomorphid ciliates in gorilla in Gabon, West Africa, were surveyed and observed by light and scanning electron microscopy. As a result, 4 species belonging to the families Troglodytellidae and Cycloposthiidae were identified, and 3 of them were new to science. These species were described as Goriliophilus thoracatus n.g., n.sp., Troglodytella gabonensis n.sp., and Prototapirella gorillae n.sp. SEM observations of Goriliophilus and Troglodytella revealed in particular the surface structures of somatic ciliary bands in which the cilia extended as rectangular tufts from uniformly distributed basements, smooth-surfaced anterior cap, armature-like ridges, and the presence of a left-ventral groove. From the similarity and difference of the morphology among these species, their phylogenetical relationships were discussed.

The Intestinal Entodiniomorph Ciliates of Wild Lowland Gorillas (Gorilla gorilla gorilla) in Gabon, West Africa

Examination of 109 fecal samples from wild lowland gorillas revealed the presence of five species of entodiniomorph ciliates: Troglodytella abrassarti, Troglodytella gorillae, and three unclassified species. These latter three species were also found in the feces of a captive gorilla in Gabon and are considered to be intestinal parasites or commensals.