Current Biology Dispatches Animal Behavior: Ape Curiosity on Camera Sofia Ingrid Fredrika Forss*, Alba Motes-Rodrigo, and Claudio Tennie Faculty of Science, Department for early prehistory and quaternary ecology, University of Tu¨ bingen, Germany *Correspondence: [email protected] https://doi.org/10.1016/j.cub.2019.02.055 How animals respond to novel objects may reflect their overall cognitive and behavioral disposition. A study using camera traps reveals that different species of wild ape respond to novelty differently. How animals react to novel situations, apes. Overall, immatures looked towards humans and our artefacts affect wild foods or objects reflects a balance camera traps the most and individuals in animals’ behavior. between neophobia (novelty avoidance) smaller parties looked at the camera traps The study of Kalan and colleagues [1] and neophilia — the drive to approach for a shorter time than lonely apes. Apes nicely complements previous results and explore, in other words components showed less interest in camera traps the reporting conservative behavior towards of curiosity. As such, animals behave closer they lived to long-term research novelty in wild orangutans. Like African according to the costs and benefits of sites. As such the authors suggest apes, wild orangutans mostly look at novel exploring something new, potentially environmental factors to reflect part of the objects and only touch them in rare dangerous. In a new study in this issue of site variation in responses. Moreover, the cases — after observing humans doing Current Biology, Ammie Kalan, Hjalmar authors propose that the observed so — suggesting orangutans use social Ku¨ hl and colleagues [1] report the species differences in camera trap cues to overcome neophobia [5].The behavioral responses of wild responses are due to variation in social study by Kalan and colleagues [1] also chimpanzees, bonobos and gorillas to structure, such as lack of clear leadership hints to within-species differences camera traps. in bonobo communities contributing to between captive and wild apes. Wild apes It is difficult to study reactions to novelty increased neophobia in this species. spend most of their wake time searching in the wild — usually this was thought to Studies on novelty responses in wild for food, mating partners, or shelter in demand field experiments where one primates are rare, and comparisons natural habitats beset with risks. must be careful not to habituate wild between species are so far lacking Consequently, for wild apes, curiosity can populations, e.g. through food (but, see [2]), making the contribution be much more costly than for their captive provisioning or through association with of Kalan and colleagues [1] highly conspecifics, who benefit from a safer humans. Consequently, studies aiming to valuable. habitat and have more time to invest in address curiosity should best avoid direct Using camera traps as stimuli is a exploration. This within-species human observation. The use of video useful first step to determine how discrepancy is referred to as the captivity camera traps, applied by Kalan and artefacts placed in nature affect wild ape effect [5–7] and explains the increased colleagues [1], is a relatively non-invasive, behaviors. But one could argue that curiosity observed in captive housed apes yet effective approach to obtain genuine the (camouflaged) camera trap itself [8]. The study by Kalan and colleagues [1] reactions to novel items in wild apes. represents a relatively uninteresting novel thus stresses the importance of studying Camera traps also enable researchers to object for wild apes. Accordingly, the curiosity in natural habitats, because solely address novelty responses with the great authors report no real fearful behaviors captive data can generate a biased picture unknown — wild animals that are not (except a few bonobo alarm calls). Thus, of ape curiosity. The between-species habituated to humans. Kalan and the most common recorded responses — differences found by Kalan and colleagues colleagues [1] studied an impressive 43 looking impulses — are best described as [1] in wild apes, where bonobos showed different groups of the three African ape indifference rather than truly neophobic or the highest frequency of neophobic species distributed across 14 sites neophilic. This highlights the importance responses, match with some previous (Figure 1). of what kind of stimulus is used when results from captivity, describing bonobos The authors found that the three assessing novelty response and to be more risk averse than chimpanzees species of African apes differed in their explorative behavior [3,4]. However, [9,10]. However, other studies on novel responses to a novel object: camera using camera traps as stimuli has the food response found that captive traps. Apes rarely touched the camera advantage that it provides a stimulus that chimpanzees show similar food neophobia traps, which indicates that neophilia, or is consistent across different sites. Such a as bonobos and more than gorillas [11,12]. the motivation to explore, was low in low degree of variation (in appearance) is Kalan and colleagues [1] assume both all three species. Compared to generally not possible to achieve when large dietary variation and differences in chimpanzees, bonobos and gorillas were humans (and their behavior) are the innovative abilities across the tested more likely to look at the camera traps. stimuli. Thus, while we also need to use species, as chimpanzees are the most Bonobos were also the most neophobic multiple stimuli when we aim to assess proficient African ape tool users. species, producing more alarm calls and curiosity, camera traps are still Consequently, the authors expected other fearful behaviors than the other informative on how the presence of chimpanzees to show higher neophilia Current Biology 29, R241–R264, April 1, 2019 ª 2019 Elsevier Ltd. R255 Current Biology Dispatches The study by Kalan and colleagues [1] draws attention to the fact that, so far, no single hypothesis can explain the variation in exploration tendency and neophobia in great apes. Ideally, future studies can disentangle environmental and social factors to clarify the relationship between exploration drive and neophobia and the conditions that elicit curiosity. Understanding curiosity in non-human primates will also shed light on the arguably extreme case of human exploration and innovation ability. Finally, natural habitats are fast changing due to human activity, causing wild populations to face new challenges. For species conservation purposes, it is now more urgent than ever to understand how different species react when faced with habitat modifications incorporating exposure to novelty. Figure 1. Gorilla on camera. Nkombe, an adult female from the Atananga Group in Gabon, taking a break from feeding. Photo: Martha REFERENCES Robbins/Loango Gorilla Project. 1. Kalan, A.K., Hohmann, G., Arandjelovic, M., Boesch, C., McCarthy, M.S., Agbor, A., than bonobos and gorillas, but in fact due to the limited field of view it is not Angedakin, S., Bailey, E., Balongelwa, C.W., chimpanzees showed the least interest in always clear how many others are around. Bessone, M., et al. (2019). Novelty response of the camera traps. 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