Researchers analyzed video from camera capture devices placed in monkeys populated throughout Africa to see how the wild monkeys would react to these unknown objects. The responses varied by species and even between individuals within the same species, but one thing was consistent throughout: the monkeys definitely noticed the cameras ̵
"Our goal was to see how chimpanzees, bonobos and gorillas react to objects unknown in the wild, mainly to determine whether the presence of research equipment, such as photographic traps, has any effect on their behavior and whether they are differences between the three great apes, "says Ammie Kalan (@ammiekalan), primatologist of the Max Planck Institute for Evolutionary Anthropology in Germany. "We were particularly surprised by the differences in the reactions we observed between chimpanzees and bonobos: since they are sister species and share much of the same genetic makeup, we expected them to react similarly to the camera, but this was not the case."
"Chimpanzees were not at all interested in camera traps – they barely seemed to notice their presence and were generally not afflicted by them," says Kalan. "Yet the bonobos seemed to be much more troubled by the photographic traps, they were hesitant in approaching and actively keeping their distance from them."
Individuals within a species also reacted differently to the cameras. For example, monkeys that live in areas with more human activities, such as near research sites, can be desensitized to unknown objects and become indifferent to such encounters in the future. However, another member of the same species that has had less exposure to strange or new objects might be more interested in them.
The age of the monkey has a similar role. "The younger monkeys would explore more camera traps by fixing them for longer periods of time," says Kalan. "Like human children, they need to get more information and learn about their environment: being curious is a way to do it."
The range of responses shown by monkeys and the complex differences between both species and individual species demonstrates the need for scientists to consider how animals will respond to the presence of unknown monitoring equipment in the their natural habitats.
"Internal and inter-species variation in behavior towards unfamiliar objects could be problematic when trying to collect accurate data monitoring," says Kalan. "To curb this effect, it would be worth having a period of familiarization, in which wild animals can get used to new objects."
Despite this potential complication, using camera traps to monitor wild animal populations is still one of the most useful options. "Our knowledge tends to be limited by the number of groups or by the number of populations we are able to study, but the use of monitoring technologies such as photographic traps is an effective way to solve this problem," he says. "I think it is really interesting from a behavioral flexibility point of view to consider how wild animals react to these new technologies: I would like more researchers to investigate the novelties during the monitoring investigations."
Study of interactions between species using remote photographic traps
Current Biology Kalan et al.: "Novelty response of African wild monkeys to photographic traps" http://www.cell.com/current-biology/fulltext/S0960-9822 (19) 30163-0, DOI: 10.1016 / j.cub.2019.02.024