Orangutans (Pongo spp.) may prefer tools with rigid properties to flimsy tools

Preference for tools with either rigid or flexible properties was explored in orangutans (Pongo spp.) through an extension of D. J. Povinelli, J. E. Reaux, and L. A. Theall’s (2000) flimsy-tool problem. Three captive orangutans were presented with three unfamiliar pairs of tools to solve a novel problem. Although each orangutan has spontaneously used tools […]

Individual Response Strategies in List Learning by Orangutans

Two orangutans learned eight lists of items in a recognition memory procedure that allowed the list items to be reported in any order. In a previous study using this same procedure, the orangutans developed a spatial response strategy that was applied to acquisition of novel lists. The purpose of the present study was to determine […]

Response strategies inlist learning by orangutans (Pongo pygmaeus × P. abelii)

Rhesus monkeys (Macaca mulatta) develop strategies to acquire and execute serial lists (K. B. Swartz & S. A. Himmanen, 2001). Serial probe recognition studies of list memory have demonstrated similarities across monkeys and humans (S. F. Sands & A. A. Wright, 1980). The present study extended the investigation of list learning and memory to determine […]

What do bonobos (Pan paniscus) understand about physical contact?

The present study aimed to test what bonobos ( Pan paniscus ) understand about contact. The task consisted of a clear horizontal tube containing a piece of food and a stick with a disk attached. The bonobos chose which side to push or pull the stick for the disk to contact the food and make […]

Are great apes tested with an abject object-choice task?

A surprising finding in comparative social cognition is that great apes seem to have difficulties understanding others’ communicative behaviour. In no other paradigm is this more evident than in the object-choice task in which subjects use a human cue, such as pointing, to infer the correct choice of a reward hidden in one of a […]

Ape consciousness-human consciousness- a perspective informed by language and culture

Animal consciousness has long been assumed to be a nonviable arena of investigation. At best, it was thought that any indications of such consciousness, should it exist, would not be interpretable by our species. Recent work in the field of language competencies with bonobos has laid this conception open to serious challenge. This paper reviews […]

Decision making across social contexts: competition increases preferences for risk in chimpanzees and bonobos

Context can have a powerful influence on decision-making strategies in humans. In particular, people sometimes shift their economic preferences depending on the broader social context, such as the presence of potential competitors or mating partners. Despite the important role of competition in primate conspecific interactions, as well as evidence that competitive social contexts impact primates’ […]

Pseudoreplication: a widespread problem in primate communication research

Pseudoreplication (the pooling fallacy) is a widely acknowledged statistical error in the behavioural sciences. Taking a large number of data points from a small number of animals creates a false impression of a better representation of the population. Studies of communication may be particularly prone to artificially inflating the data set in this way, as […]

Evaluating the physiological and behavioral response of a male and female gorilla (Gorilla gorilla gorilla) during an introduction

Prolonged stress responses can lead to infertility and death; therefore monitoring respective indicators like stress-related hormones and behaviors is an important tool in ensuring the health and well-being among zoo-housed animal populations. Changes in social structure, such as the introduction of a new conspecific, can be a source of stress. In April 2010, a sexually […]

Personality and social dynamics of zoo-housed western lowland gorillas (Gorilla gorilla gorilla)

Western lowland gorillas are among the most studied non-human primates. However, managing them in captivity is not without its challenges. Understanding individual differences between gorillas, as well as differences in group dynamics may be of high value in these apes’ more efficient captive management. Predicting behaviour may be especially useful, particularly in terms of affiliative […]