Poaching fuelled by international trade in horn caused the deaths of over 1000 African rhinoceros ( Ceratotherium simum and Diceros bicornis ) per year between 2013 and 2017. Deterrents, which act to establish avoidance behaviours in animals, have the potential to aid anti-poaching efforts by moving at-risk rhinos away from areas of danger (e.g. near perimeter fences). To evaluate the efficacy of deterrents, we exposed a population of southern white rhinos ( C. simum simum ) to acoustic- (honeybee, siren, turtle dove), olfactory- (chilli, sunflower), and drone-based stimuli on a game reserve in South Africa. We exposed rhinos to each stimulus up to four times. Stimuli were considered effective deterrents if they repeatedly elicited avoidance behaviour (locomotion away from the deterrent). Rhinos travelled significantly further in response to the siren than to the honeybee or turtle dove stimulus, and to low-altitude drone flights than to higher altitude flights. We found the drone to be superior at manipulating rhino movement than the siren owing to its longer transmission range and capability of pursuit. By contrast, the scent stimuli were ineffective at inciting avoidance behaviour. Our findings indicate that deterrents are a prospective low-cost and in situ method to manage rhino movement in game reserves.

Prior herpetological surveys in 1996 and 2000 identified 14 species of amphibians and 32 species of reptiles from the Sahamalaza Peninsula. This work increases the total number of amphibian and reptile species known from this area to 20 and 43 respectively. To maximise our chances of species detection, survey effort covered the entire wet season and part of the dry season, and utilised a combination of opportunistic searching, transect searching, pitfall trapping, and acoustic recording. We identified species through an integrative taxonomic approach, combining morphological, bioacoustic and molecular taxonomy. Together, this enabled the detection of cryptic and seasonally inactive species that were missed in the shorter prior surveys that relied on morphological identification alone. The taxonomic identification of amphibians utilised a fragment of the mitochondrial 16S rRNA gene; taxonomic identification of reptiles utilised a fragment of the mitochondrial COI gene, and when necessary, also mitochondrial fragments of the 16S rRNA ND1, ND2, ND4 genes. All sequences were deposited in Genbank and COI sequences were also deposited in the BOLD database to foster taxonomic identification of malagasy reptiles. We report two new taxa: a species of Boophis, since described as B. ankarafensis, and a candidate new species of microhylid (genus: Stumpffia). We document range expansions of Boophis tsilomaro, Cophyla berara, Blaesodactylus ambonihazo beyond their type localities. Along with significant range expansions across a range of taxa, including Blommersia sp. Ca05, Boophys brachychir, Brookesia minima, Ebenavia inunguis, Geckolepis humbloti, Madascincus stumpffi, Pelomedus subrufa and Phelsuma kochi. Forest in the peninsula is under extreme pressure from human exploitation. Unless unsustainable agricultural and pastoral practices encroaching on these habitats halt immediately, both forest and the species that occur there, several of which appear to be local endemics, may be irreversibly lost.

White-handed gibbons produce loud and acoustically complex songs when interacting with their neighbours or when encountering predators. In both contexts, songs are assembled from a small number of units although their composition differs in context-specific ways. Here, we investigated whether wild gibbons could infer the ‘meaning’ when hearing exemplars recorded in both contexts (i.e. ‘duet songs’ vs. ‘predator songs’). We carried out a playback experiment by which we simulated the presence of a neighbouring group producing either its duet or a predator song in order to compare subjects’ vocal and locomotor responses. When hearing a recording of a duet song, subjects reliably responded with their own duet song, which sometimes elicited further duet songs in adjacent groups. When hearing a recording of a predator song, however, subjects typically remained silent, apart from one of six groups which replied with its own predator song. Moreover, in two of six trials, playbacks of predator songs elicited predator song replies in non-adjacent groups. Finally, all groups showed strong anti-predator behaviour to predator songs but never to duet songs. We concluded that white-handed gibbons discriminated between the two song types and were able to infer meaning from them. We discuss the implications of these findings in light of the current debate on the evolutionary origins of syntax.