Does the Absence of Zoo Visitors during the COVID-19 Pandemic Impact Gorilla Behavior?
Whether or not primates are behaviorally affected by the presence of visitors in a zoo setting is a question of great relevance to zoo animal well-being. The situation imposed by the COVID-19 pandemic provided an unusual opportunity to examine how the absence of visitors impacts behavior. We took advantage of this opportunity to study the […]
Impact of alternating overnight housing conditions on welfare measures in a bachelor group of western lowland gorillas (Gorilla gorilla gorilla)
Spatial parameters and design of overnight housing spaces can have significant influences on both nocturnal and diurnal behaviors of western lowland gorillas (Gorilla gorilla gorilla) in captivity. This is especially true for bachelor groups, as adult males have demonstrated a greater tendency to separate from conspecifics overnight. Additionally, previous studies have suggested that the social […]
A food for all seasons: Stability of food preferences in gorillas across testing methods and seasons
Decisions about which foods to use during training and enrichment for captive animals may be based on invalid assumptions about individuals’ preferences. It is important to assess the stability of food preferences given that one-time preferences are often used to inform which items are offered over a longer period of time. Presenting preference assessments using […]
Who is there? Captive western gorillas distinguish human voices based on familiarity and nature of previous interactions
The ability to recognize conspecifics by their acoustic signals is of crucial importance to social animals, especially where visibility is limited, because it allows for discrimination between familiar and unfamiliar individuals and facilitates associations with and the avoidance of particular conspecifics. Animals may also benefit from an ability to recognize and use the information coded […]
Silence is Golden: Auditory Preferences in Zoo-housed Gorillas
Enrichment is presented to improve the welfare of captive animals but sound is frequently presented with the assumption that it is enriching without assessing individuals’ preferences. Typically, presented sounds are unnatural and animals are unable to choose which sounds they can listen to or escape them. We examined preferences of three zoo-housed gorillas for six […]
Behavioral Implications of the Complete Absence of Guests on a Zoo-Housed Gorilla Troop
Research conducted on the effects that zoo visitors have on primate behavior has yielded inconsistent patterns. This study aims to contribute to the growing body of literature regarding visitor effects on zoo-housed primate’s activity budgets, with the purpose of quantifying the behavioral variability under two conditions: guest presence and guest absence. Due to the COVID-19 […]
In or out: Response slowing across housing conditions as a measure of affect in three Western lowland gorillas (Gorilla gorilla gorilla)
Individuals experiencing negative affect have shown response slowing, a longer latency to respond in relation to baseline, when presented with aversive stimuli. We assessed response slowing in three male gorillas housed in a bachelor group as a function of daytime and nighttime housing arrangements.
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 […]
Impacts of dietary modifications on the behaviour of captive western lowland gorillas (Gorilla gorilla gorilla)
Behavioural profiles of captive and wild Gorilla gorilla gorilla have been shown to differ greatly, with captive gorillas moving and foraging much less than their wild counterparts and often experiencing high levels of obesity and cardiovascular disease. Captive gorillas are typically fed an energy dense diet and housed in relatively small enclosures compared to wild […]
Exploratory Investigation of Infrared Thermography for Measuring Gorilla Emotional Responses to Interactions with Familiar Humans
Interactions between zoo professionals and animals occur regularly and are believed to be enriching for animals. Little empirical information exists on how animals perceive these interactions, and particularly how the interactions affect the emotional states of animals. Infrared thermography (IRT) has shown some promise in the assessment of emotions in a variety of species, but […]