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 […]

Evaluating mood changes in response to anthropogenic noise with a response-slowing task in three species of zoo-housed primates

In the zoo environment, anthropogenic noise is common as sound levels fluctuate due to visitors, construction, habitat design, and special events. In this study, changes in the mood of three species of zoo-housed primates in response to a loud annual event were evaluated with the response-slowing paradigm. In this paradigm, animals experiencing anxiety slow responses […]

Male chimpanzees form enduring and equitable social bonds

Controversy exists regarding the nature of primate social relationships. While individual primates are frequently hypothesized to form enduring social bonds with conspecifics, recent studies suggest that relationships are labile, with animals interacting only over short periods to satisfy their immediate needs. Here I use data collected over 10 years on a community of chimpanzees, Pan […]

Variables Influencing the Origins of Diverse Abnormal Behaviors in a Large Sample of Captive Chimpanzees (Pan troglodytes)

The developmental origin of abnormal behaviors is generally associated with early rearing environments that lack sufficient physical and sensory stimulation. However, other factors should also be considered. A large sample of captive chimpanzees (128 males and 140 females) was surveyed for the presence or absence of 18 abnormal behaviors. Origin variables included the subject’s source […]

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 Poor Contribution of Chimpanzee Experiments to Biomedical Progress

Biomedical research on captive chimpanzees incurs substantial nonhuman animal welfare, ethical, and financial costs that advocates claim result in substantial advancements in biomedical knowledge. However, demonstrating minimal contribution toward the advancement of biomedical knowledge generally, subsequent papers did not cite 49.5% (47/95), of 95 experiments randomly selected from a population of 749 published worldwide between […]

Positive reinforcement training as a technique to alter nonhuman primate behavior: Quantitative assessments of effectiveness

Many suggest that operant conditioning techniques can be applied successfully to improve the behavioral management of nonhuman primates in research settings. However, relatively little empirical data exist to support this claim. This article is a review of several studies that discussed applied positive reinforcement training techniques (PRT) on breeding/research colonies of rhesus macaques (Macaca mulatta) […]

Controllability in Environmental Enrichment for Captive Chimpanzees (Pan troglodytes)

This study considers the use of nonsocial environmental enrichment by captive chimpanzees at the Primate Foundation of Arizona. The goal was to determine whether a relationship existed between controllability of enrichment items by captive chimpanzees and frequency of use. The study measured controllability, the ability of nonhuman animals to alter aspects of their environment by […]

Successful formation of a large chimpanzee group out of two preexisting subgroups

Abstract 10.1002/zoo.10003.abs Descriptions of the formation of relatively large groups of unfamiliar chimpanzees (Pan troglodytes) in captivity are scarce in the literature. Nineteen chimpanzees from preexisting subgroups were introduced into a social group at the Yerkes Regional Primate Research Center. The group included two adult males, six adult females along with six dependent infants, and […]

Birth of a chimpanzee (Pan troglodytes) after artificial insemination with cryopreserved epididymal spermatozoa collected postmortem

Abstract A male chimpanzee (Pan troglodytes) suddenly died of acute hemorrhagic enteritis at the age of 18 years. Within 24 hours after its death, a large quantity of spermatozoa of excellent quality was recovered from the distal cauda epididymides and was subsequently cryopreserved. After storage for 67 days, the frozen spermatozoa were thawed and inseminated […]