scholarly journals No evidence that horn trimming affects white rhinoceros horn use during comfort behaviour and resource access

2021 ◽  
pp. 1-17
Author(s):  
Samuel G. Penny ◽  
Rachel L. White ◽  
Dawn M. Scott ◽  
Lynne MacTavish ◽  
Angelo P. Pernetta

Abstract Rhino species use their horns in social interactions but also when accessing resources, rubbing and in interspecific defence. The current poaching crisis has seen southern white rhinos (Ceratotherium simum simum) increasingly dehorned as a conservation management practise, but few studies have evaluated whether the procedure has any behavioural effects. This study sought to document and describe horn-contingent behaviours during resource access, wallowing and rubbing in freeranging white rhinos and establish whether dehorning, also known as horn trimming, impacts on their frequency or function. Data were collected through camera trapping and field observations at two sites in South Africa. The results provide no evidence that dehorning disrupts digging behaviours during mineral consumption or wallowing and suggests that dehorning is unlikely to have a strong biological impact on resource access. Furthermore, the frequency of horn-rubbing behaviours did not appear to be influenced by levels of horn growth. This suggests the procedure has a limited impact on these aspects of the species’ ecology and provides support that dehorning can be employed as a management tool to reduce poaching in freeranging populations of white rhino.

2019 ◽  
Vol 34 ◽  
pp. 36-45 ◽  
Author(s):  
D.D.G. Lagendijk ◽  
R.A. Howison ◽  
P. Esselink ◽  
C. Smit

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0200347 ◽  
Author(s):  
Emma H. Hooijberg ◽  
Michele Miller ◽  
Carolyn Cray ◽  
Peter Buss ◽  
Gerhard Steenkamp ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Julia Jenikejew ◽  
Brenda Chaignon ◽  
Sabrina Linn ◽  
Marina Scheumann

Abstract Vocal communication networks can be linked to social behaviour, allowing a deeper understanding of social relationships among individuals. For this purpose, the description of vocal dyads is fundamental. In group-living species, this identification is based on behavioural indicators which require a high level of reactivity during social interactions. In the present study, we alternatively established a proximity-based approach to investigate whether sex-specific differences in vocal communication reflect social behaviour in a species with rather loose social associations and low levels of reactivity: the Southern white rhinoceros (Ceratotherium simum simum). We performed audio- and video recordings of 30 captive animals from seven groups. Vocal networks for the four most common call types were constructed by considering conspecifics at close distance (≤ 1 body length) to the sender as potential receivers. The analysis of the resulting unidirectional structures showed that not only the sex of the sender but also the sex of the potential receiver, the quality of social interactions (affiliative or agonistic) as well as association strength predict the intensity of vocal interactions between group members. Thus, a proximity-based approach can be used to construct vocal networks providing information about the social relationships of conspecifics—even in species with loose social associations where behavioural indicators are limited.


2019 ◽  
Vol 12 (5) ◽  
Author(s):  
Wing Yan Chan ◽  
Ary A. Hoffmann ◽  
Madeleine J. H. Oppen

Endocrinology ◽  
2012 ◽  
Vol 153 (3) ◽  
pp. 1444-1452 ◽  
Author(s):  
Christopher Tubbs ◽  
Phillip Hartig ◽  
Mary Cardon ◽  
Nicole Varga ◽  
Matthew Milnes

The captive southern white rhinoceros (SWR; Ceratotherium simum simum) population serves as an important genetic reservoir critical to the conservation of this vulnerable species. Unfortunately, captive populations are declining due to the poor reproductive success of captive-born females. Captive female SWR exhibit reproductive problems suggested to result from continual ovarian follicular activity and prolonged exposure to endogenous estrogen. However, we investigated the potential role of exogenous dietary phytoestrogens in the reproductive failure of SWR by cloning and characterizing in vitro phytoestrogen binding and activation of recombinant SWR estrogen receptors (ESR). We compared those characteristics with recombinant greater one-horned rhinoceros (GOHR; Rhinoceros unicornis) ESR, a species that receives similar captive diets yet reproduces relatively well. Our results indicate that phytoestrogens bind rhino ESR in a manner similar to other vertebrate species, but there are no differences found in phytoestrogen binding affinity of SWR ESR compared with GOHR ESR. However, species-specific differences in ESR activation by phytoestrogens were detected. The phytoestrogen coumestrol stimulated greater maximal activation of SWR ESR1 than GOHR ESR1. SWR ESR2 were also more sensitive to phytoestrogens and were activated to a greater extent by both coumestrol and daidzein. The concentrations in which significant differences in ESR activation occurred (10−7 to 10−5m) are consistent with circulating concentrations measured in other vertebrate species. Taken together, these findings suggest that phytoestrogens potentially pose a risk to the reproductive health of captive SWR. However, additional studies are needed to further clarify the physiological role of dietary phytoestrogens in the reduced fertility of this species.


Oryx ◽  
1967 ◽  
Vol 9 (2) ◽  
pp. 137-150 ◽  
Author(s):  
Ian Player

The history of wildlife conservation in Africa is one of dwindling animal populations and shrinking habitats, and the southern white or square-lipped rhinoceros Ceratotherium simum simum became one of the rarest large mammals in Africa. This paper, on which the author's address at San Diego was based, describes one of the most successful operations in wildlife conservation, the build-up n i numbers of the white rhino and the re-population of some of its former range, thanks largely to the use of immobilising drugs. Ian Player, who played a major part in the operations, is Chief Conservator of Zululand.


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