Impact of Different Forms of Environmental Enrichment on Foraging and Activity Levels in Gorillas (Gorilla gorilla gorilla)

The maintenance of species-specific behaviors for animals in zoological institutions is of top priority, as this can help ensure high levels of animal welfare. Strict feeding schedules within institutions can often impact natural foraging behaviors of animals, as they are no longer required to seek out or manipulate food items. In the wild, western lowland […]

Using an Ambiguous Cue Paradigm to Assess Cognitive Bias in Gorillas (Gorilla gorilla gorilla) during a Forage Manipulation

In nonhumans, ‘optimism’ is often defined as responding to an ambiguous item in the same manner as to items previously associated with reward (or lack of punishment), and “pessimism” is defined as responding to an ambiguous item in the same manner as to items previously associated with a lack of reward (or with punishment). We […]

Visual Processing of Faces in Juvenile Western Lowland Gorillas without the Use of Training or Reinforcement: A Pilot Study

Cognitive research in zoos is often limited by an inability to consistently train and reinforce subjects. This feasibility study aims to address this problem by examining visual processing of faces by Western lowland gorillas (Gorilla gorilla) at a zoo in order to identify gaze patterns without any training or reward. A Tobii Pro X2-30 eye-tracker […]

Personality in the behaviour of great apes: temporal stability, cross-situational consistency and coherence in response

Using a multidisciplinary approach, the present study complements ethological behaviour measurements with basic theoretical concepts, methods and approaches of the personality psychological trait paradigm. Its adoptability and usefulness for animal studies are tested exemplarily on a sample of 20 zoo-housed great apes (five of each of the following species): bonobos, Pan paniscus; chimpanzees, Pan troglodytes […]

The prevalence of osteoarthritis in wild versus captive great ape skeletons

This research examined whether the prevalence and skeletal distribution of osteoarthritis (OA) differed between wild and captive great ape skeletons. A secondary, but important, aspect of this research focused on the development of improved aging techniques based on methods commonly used on human osteological samples. Tests were conducted pertaining to the effect that wild versus […]

Home-range use and intergroup encounters in western gorillas (Gorilla g. gorilla) at Lossi forest, North Congo

I present data on home-range use and types of intergroup encounters for one group (Apollo) of western gorillas (Gorilla gorilla gorilla) from a new study site in the Republic of Congo. The total home-range size of the focal group, which I calculated by superimposing a 100 m 100 m grid over the mapped daily path […]

Group differences in captive gorillas’ reaction to large crowds

The impact of visitor crowd size on captive animal behaviour can be difficult to interpret in many institutions due to the lack of variation in crowd size over short periods of time. In attempts to compare greater variation in crowd size, animal behaviour is often compared over conditions that create additional confounds, such as day […]

Gorilla Behavior Index revisited: Age, housing and behavior

While personality and temperament assessments are becoming more common in animal science as a means for predicting behavior patterns, they are virtually unstudied in exotic animals outside of chimpanzees. We assessed behavioral profiles of 119 male gorillas using the Gorilla Behavior Index (GBI) and paired this assessment with behavior data on 25 male gorillas from […]

An experimental, comparative investigation of tool use in chimpanzees and gorillas

Studies of ape tool use have been conducted in captivity since the early 1900s and in the wild since the 1960s. Chimpanzees are the most prolific tool users among the apes, and are known to use more tools than any other nonhuman animal. In contrast, reports of gorilla tool use are rare both in wild […]

The Use of Psychopharmaceuticals to Control Aggressive Behaviors in Captive Gorillas

Unusually aggressive and violent behavior was seen in a captive twelve-year-old western lowland gorilla (Gorilla gorilla gorilla) during and after introduction to a group of two adult females and two juvenile male gorillas at the Franklin Park Zoo. In an attempt to control the aggression and minimize injuries, several psychopharmological drugs (drugs used to treat […]