Wild chimpanzees' use of single and combined vocal and gestural signals

We describe the individual and combined use of vocalizations and gestures in wild chimpanzees. The rate of gesturing peaked in infancy and, with the exception of the alpha male, decreased again in older age groups, while vocal signals showed the opposite pattern. Although gesture-vocal combinations were relatively rare they were consistently found in all age groups, especially during affiliative and agonistic interactions. Within behavioural contexts rank (excluding alpha-rank) had no effect on the rate of male chimpanzees’ use of vocal or gestural signals and only a small effect on their use of combination signals. The alpha male was an outlier, however, both as a prolific user of gestures and recipient of high levels of vocal and gesture-vocal signals. Persistence in signal use varied with signal type: chimpanzees persisted in use of gestures and gesture vocal combinations after failure, but where their vocal signals failed they tended to add gestural signals to produce gesture-vocal combinations. Overall, chimpanzees employed signals with a sensitivity to the public/private nature of information, by adjusting their use of signal types according to social context and by taking into account potential out of-sight audiences. We discuss these findings in relation to the various socio-ecological challenges that chimpanzees are exposed to in their natural forest habitats and the current discussion of multimodal communication in great apes.Publisher PDFPeer reviewe

Global COVID-19 lockdown highlights humans as both threats and custodians of the environment

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness