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Role of delinquent young "orphan" male elephants in high mortality of white rhinoceros in Pilanesberg National Park, South Africa
Abstract
We describe white rhinoceros (Ceratotherium simum) mortality at Pilanesberg National Park, South Africa, focussing on mortality caused by African elephant (Loxodonta africana). We reconstructed records from a range of historical sources, and estimated that up to 49 rhino were killed by elephant. There was confirmed mortality in 1994 and 1996, and based on patterns, we suggest a set of rhino mortality from elephant in 1992. Both sexes and all age classes were victims. There was no significant bias to older animals, but given the rhino population structure, there was a significant bias towards males in adult deaths. The culprits were identified as young male elephants that entered musth about 10 years younger than expected, and maintained musth for a full term at first occurrence. We attributed this to the lack of a mature bull hierarchy in the park, because these elephants were the product of translocation of young animals(<10 years old)remaining from culls in Kruger National Park. We emphasise the need for accurate monitoring and record keeping, and a focus on individual identification of key species in small reserves.
... Breeding herds consistently preferred reservoirs throughout both seasons across all daily periods (Figs 5A and 6A). This suggests that female herd members may not tolerate bachelor groups, aligning with documented behaviour in the literature [34,51]. Bachelor groups, composed of young males testing their strength, could pose a risk of injury to young elephants within herds [32,34,51]. ...
... This suggests that female herd members may not tolerate bachelor groups, aligning with documented behaviour in the literature [34,51]. Bachelor groups, composed of young males testing their strength, could pose a risk of injury to young elephants within herds [32,34,51]. Solitary mature bachelor elephants often linger near herds, waiting for mating opportunities with herd cows [34]. ...
... Simultaneous use of waterholes by young elephant bachelor groups, black rhinos and white rhinos in areas where there are no large adult elephant bulls has been problematic in the past [51]. Several white rhino deaths were recorded in Pilanesberg National Park when young elephant bulls intimidated rhinos at waterholes in episodes of what were observed as young bachelor elephants trying to mate with rhinos [51]. ...
Artificial water provisioning is a common practice in southern African nature reserves, where different game species exhibit preferences for specific waterhole types. The movement patterns and behaviour of elephants and rhinos are closely linked to water availability, with these mega-herbivores noticeably influencing the environment and other species they interact with at waterholes. Since there is limited research on this topic, understanding preferences for different types of artificial waterholes is crucial, particularly during periods of water scarcity. This knowledge enables reserve managers to effectively manage the numbers and types of waterholes. In this study, we investigate artificial waterhole selection and preferences by elephants and rhinos in the Olifants West Nature Reserve, South Africa. The study area featured various waterhole types, including earth dams, concrete pans, reservoirs, and troughs. By employing camera traps, we analysed visitation frequency, timing of visits, and factors influencing visit frequency. Our findings revealed distinct preferences for specific waterhole types among different social groupings of the study species. Breeding herds of elephants predominantly utilized reservoirs and occasionally visited troughs, while bachelor herds favoured earth dams. Black rhinos showed a preference for earth dams, whereas white rhinos selected troughs and earth dams, with bachelor groups favouring troughs and female rhinos favouring earth dams. The outcomes of this study have significant implications for the development of comprehensive conservation plans in areas where these species reside, and for potential release sites.
... African elephants, Loxodonta africana Blumenbach, 1797, have been killing both black (n = 5) and white rhinos (n = 58), mainly through tusk wounds made to the shoulder and chest area. This abnormal behaviour has been described from a number of reserves but has mainly occurred in Pilanesberg National Park (PNP), where between 1992 and 1997 elephants killed up to 50 white rhinos (Slotow and van Dyk 2001). The culprit elephants were young males (17-25 years old) who were entering a state of musth (heightened aggression from elevated hormones associated with reproductive competition-Poole and Moss 1981) well ahead of schedule-from 18 years of age as opposed to a normal age of 28 years (Poole 1987)-and were doing so because of the absence of an older male hierarchy (Slotow et al. 2000). ...
... The rhinos being killed are predominantly adults, and slightly more males than females. A similar pattern was observed in PNP, where all ages and both sexes of rhinos were killed (Slotow and van Dyk 2001). There is no indication that deaths are related to rhino territorial behaviour. ...
Between 1991 and 2001 elephants killed 58 white and 5 black rhinos in Hluhluwe-Umfolozi. The culprits were primarily young male elephant entering musth at a younger than normal age due to the absence of older bulls. Elephant bulls (17-25 years) translocated as young animals from Kruger NP culls had no older male hierarchy, and were entering into musth as early as 18 as opposed to an average age of 28. (Poole 1987). Carcasses were often found in the vicinity of rivers, 76% being within 1 km of a river. Rhinos killed were predominately adult (86%), and slightly more males than females. This situation was similar to that in Pilanesberg NP (50 white rhinos killed 1992-1997) which was suppressed when 6 older bulls were introduced. In May 2000 10 older bulls from Kruger NP were introduced to Hluhluwe-Umfolozi. The number of rhino deaths decreased immediately, between September 2000 and October 2001 only 2 were killed (both in June 2001). Results suggest when rhino are present in an area older male elephants should be brought into a population of young introduced animals, but numbers should be on the conservative side monitored to assess vegetation/habitat utilization as well as interspecific aggression.
... Behavioral responses to traumatic events may also shed light on elephant memory. For example, groups of orphaned African savanna elephants have been reported killing rhinoceroses in displays of hyperaggression (Bradshaw et al., 2005;Slotow & van Dyk, 2001). This behavior may be consistent with behaviors related to posttraumatic stress syndrome (PTSD; Bradshaw et al., 2005), where individuals experience a traumatic event-in this case, young elephants witnessing family members being killed by humans-and then, later in life, engage in fear-related and aggressive behaviors that are not related to the cause of the traumatic event. ...
... However, these orphan elephants also experienced altered musth patterns (i.e., early onset and long durations). In addition, when older bulls were introduced into these young male elephant groups, young male musth (presumably along with associated elevated testosterone levels) was suppressed, and displays of hyperaggression ended (Bradshaw et al., 2005;Slotow & van Dyk, 2001). Therefore, it is possible that this behavior was simply due to a lack of social structure, and not necessarily due to the recollection of a traumatic event. ...
Despite popular culture’s promotion of the elephant’s ability to “never forget,” there is remarkably limited empirical research on the memory capacities of any living elephant species (Asian, Elephas maximus; African savanna, Loxodonta africana; African forest, Loxodonta cyclotis). A growing body of literature on elephant cognition and behavioral ecology has provided insight into the elephant’s ability to behave flexibly in changing physical and social environments, but little direct evidence of how memory might relate to this flexibility exists. In this paper, we review and discuss the potential relationships between what we know about elephant cognition and behavior and the elephants’ memory for the world around them as they navigate their physical, social, and spatial environments. We also discuss future directions for investigating elephant memory and implications for such research on elephant conservation and human–elephant conflict mitigation.
... Despite the persistent myth that males are solitary, a growing body of evidence shows that, like females, male elephants socialize have longstanding bonds and friendships , depend on knowledgeable others (Allen et al. 2020), and require social stability for individuals to develop successfully (Slotow and Dyk 2001). How then do males manage this transition from a matriarchal multigenerational family structure, to mature individuals balancing friendships and the intensity of male-male competition (Evans and Harris 2008;Poole et al. 2011;Murphy et al. 2019)? ...
... Pilanesberg National Park (PNP), South Africa. Between 1979 and 1998, 93 elephants, 121 mostly young orphan survivors from culling operations elsewhere in South Africa, were 122 translocated to PNP from at least six different locations (Slotow and van Dyk 2001). Over 123 the four decades that followed, the PNP elephant population has grown substantially 124 (Slotow et and especially so when surveying small populations (Barnes 2002 Goswami et al. 2007). ...
... For reviews of details, see Moss et al (2011), Bradshaw (2009), Ross (2019, and Wrage et al (2023). A widely reported instance of elephant norm enforcement, almost certainly mediated through but not reducible to hormonal regulation, was observed in several South African reserves where herds of young bulls orphaned by culls committed recurrent lethal violence against rhinoceroses, which ceased almost immediately when older bulls from elsewhere in Africa were introduced to restore normal conduct (Slotow et al 2000;Slotow and van Dyk 2001). ...
Comparative cognitive science of humans has tended to overwhelmingly emphasize similarities and differences between humans and other living hominids, particularly chimpanzees and bonobos. In thus under-emphasizing convergent evolution, this skew systematically misidentifies several crucial explanatory targets, particularly where cultural evolution is concerned. While concentration within the hominid and wider primate lines can tell us much about genetic constraints on human culture and cognition, at least as much attention should be paid to species in which patterns of evolved social cognition respond to problems faced by ancestral hominins. Elephants furnish a first and closest example.
Veit (2023) provides a framework for modelling and empirically investigating varieties of consciousness as a Darwinian phenomenon, based on abduction from life histories of animals. The alleged ‘hard problem’ is exposed as an artefact of ignoring mechanisms by which increasingly complex varieties of consciousness evolved under selection pressure over evolutionary time. I illustrate Veit’s approach through a case study of a highly complex but non-human variety, consciousness in African elephants. This is useful for specifying more exactly the kind of anthropocentrism that Veit criticises.
This handbook lays out the science behind how animals think, remember, create, calculate, and remember. It provides concise overviews on major areas of study such as animal communication and language, memory and recall, social cognition, social learning and teaching, numerical and quantitative abilities, as well as innovation and problem solving. The chapters also explore more nuanced topics in greater detail, showing how the research was conducted and how it can be used for further study. The authors range from academics working in renowned university departments to those from research institutions and practitioners in zoos. The volume encompasses a wide variety of species, ensuring the breadth of the field is explored.
With the escalating challenges in captive elephant management, the study of elephant reintegration emerges as a pivotal area of research, primarily addressing the enhancement of animal welfare. The term ‘reintegration’ refers to the process of rehabilitating captive elephants to a natural system, allowing them to roam freely without intensive human intervention. There is a relative paucity of research addressing the behavioural adaptations post-reintegration, despite reintegration of over 20 elephants across various fenced reserves in South Africa. Our study centres on two distinct herds of reintegrated African elephants, monitoring their movement patterns in two South African reserves over a 57-month period post-release. The primary goal of the study was to establish whether the flexibility and adaptability of movement behaviour of reintegrated elephants can be considered as one of the indicators of determining the success of such an operation. The second aim of our study was to investigate if the reintegrated elephants demonstrated an adaptability to their environment through their hourly, daily, and seasonal ranging patterns after a period of free roaming that exceeded 4 years. Our findings indicated that reintegrated elephants, much like their wild counterparts (movement based on literature), displayed notable seasonal and diurnal variations in key movement parameters, such as utilisation distribution areas and reserve utilization. These patterns changed over time, reflecting an adaptive shift in movement patterns after several years of free roaming. Notably, the trajectory of changes in movement parameters varied between herds, indicating unique adaptation responses, likely resulting from differences in the reintegration process (familiarity of reserve, season of release, presence of wild elephants). Although our study is constrained by the limited number of reintegrated herds available for analysis, it underscores the potential of captive elephants to successfully adapt to a free-living environment, emphasising the promising implications of reintegration initiatives.
The influence of protected areas on the growth of African savannah elephant populations is inadequately known. Across southern Africa, elephant numbers grew at 0.16% annually for the past quarter century. Locally, much depends on metapopulation dynamics—the size and connections of individual populations. Population numbers in large, connected, and strictly protected areas typically increased, were less variable from year to year, and suffered less from poaching. Conversely, populations in buffer areas that are less protected but still connected have more variation in growth from year to year. Buffer areas also differed more in their growth rates, likely due to more threats and dispersal opportunities in the face of such dangers. Isolated populations showed consistently high growth due to a lack of emigration. This suggests that “fortress” conservation generally maintains high growth, while anthropogenic-driven source-sink dynamics within connected conservation clusters drive stability in core areas and variability in buffers.
As large-bodied mammals become restricted to progressively smaller fragments of former habitat, competitive interactions and interspecies aggression are likely to intensify. Data on the outcomes of 159 encounters between endangered African pachyderms revealed that: (1) female elephants (Loxodonta africana) dominated both sexes of black rhinos (Diceros bicornis); and (2) rhino males but not females displaced elephant bulls. The results of an additional 127 interactions involving pachyderms and 12 additional mammals ranging in size from cheetahs (Acinonyx jubatus) to giraffe (Giraffa camelopardalis) indicates that females of either pachyderm deny immediate access to limited resources. Although the evolution of gender-specific asymmetries in interspecific dominance has received little formal study, it may best be explained by understanding patterns of parental investment; however, from a conservation perspective, one consequence of size-related dominance is that with continued containment of elephants and rhinos in managed reserves, the most handicapped species are likely to be the smaller ones.