Lycaon Pictus Research Articles

Spatial genetic patterns in African wild dogs reveal signs of effective dispersal across southern Africa

Across much of Africa, decades of civil war, land reforms, and persecution by humans have decimated wildlife populations. African wild dogs (Lycaon pictus) have declined dramatically during the past decades, but have shown recent natural recolonisation of some areas. In Angola, they were rediscovered after almost five decades when no surveys were being conducted, and they have recolonised areas in southern Zimbabwe and northern South Africa. Wild dogs were also reintroduced to Mozambique, where only few individuals remained. Against this backdrop, understanding genetic structure and effective dispersal between fragmented populations is essential to ensure the best conservation approaches for the long-term survival of the species. Our study investigated population genetic diversity, differentiation and gene flow of wild dogs across southern Africa, to include areas where they have recently been rediscovered, reestablished or reintroduced. Our results point to four weakly differentiated genetic clusters, representing the lowveld of Zimbabwe/Limpopo, Kruger NP, Angola/KAZA-TFCA, and the managed metapopulation, counterbalanced by moderate levels of effective dispersal on a southern African scale. Our results suggest that if the human footprint and impact can be significantly minimized, natural dispersal of wild dogs could lead to the demographic recovery of the species in southern Africa.

Reduced injury risk links sociality to survival in a group-living primate

Sociality has been linked to a longer lifespan in many mammals, including humans. Yet, how sociality results in survival benefits remains unclear. Using 10 years of data and over 1,000 recorded injuries in rhesus macaques (Macaca mulatta), we tested two injury-related mechanisms by which social status and affiliative partners might influence survival. Injuries increased individual risk of death by 3-fold in this dataset. We found that sociality can affect individuals' survival by reducing their risk of injury but had no effect on the probability of injured individuals dying. Both males and females of high social status (measured as female matrilineal rank and male group tenure) and females with more affiliative partners (estimated using the number of female relatives) experienced fewer injuries and thus were less likely to die. Collectively, our results offer rare insights into one mechanism that can mediate the well-known benefits of sociality on an individual's fitness.

A new offloading method in the green mobile cloud computing based on a hybrid meta-heuristic algorithm

Mobile Cloud Computing (MCC) results from the evolution of several Internet-based technologies that allow mobile consumers to gain cloud computing advantages and attain green computing by utilizing their cellphones. MCC's use may be restricted because of increasing energy utilization and restricted access to energy supplies. This challenge may be tackled using the green approach, which entails the development of several algorithms or approaches to attain the highest possible degree of service quality. Several techniques in this idea allow consumers to offload data processing and storage to cloud-based servers to reduce the energy utilization of mobile nodes. Offloading is an essential element that helps MCC reduce task load and optimize data storage utilizing a cloud resource pool. Regarding the advantages of the offloading procedure, issues such as reliability (node failure), energy efficiency (energy consumption, task processing), and time management (execution time and task deadline) must be handled. This work presents a unique offloading approach in green MCC depending on a hybrid meta-heuristic algorithm because of the NP-Hard nature of the issue. The African Wild Dog Algorithm (AWDA) and the cellular learning automata technique are merged to generate better responses. AWDA is based on the cooperative hunting behavior of African wild dogs. The quantity of cooperative hunters determines the efficacy of hunting. The optimization procedure is analogous to this collective hunting behavior. Furthermore, a learning automaton in the cellular learning automata technique describes each of these components. An element's learning automaton seeks to discover which action best complements its surrounding components. The simulation findings illustrated that the suggested hybrid technique outperforms the other algorithms regarding energy consumption, delay time, and cost. The proposed algorithm has improved the delay time, cost, and energy metric by 0.43%, 3.17%, and 8.37%, compared to other algorithms.

Fence management and time since pack formation influence African wild dog escapes from protected areas in South Africa

In human-dominated and highly fragmented landscapes, keeping wildlife within reserve boundaries is vital for conservation success. In South Africa, fences are a widely employed conservation management tool for protected areas and are successful in mitigating human-wildlife conflict. However, fences are permeable, and predators are able to cross through reserve fences. African wild dogs (Lycaon pictus) often leave fenced boundaries, resulting in high capture and translocation costs. Moreover, when wild dog packs (up to 30 individuals) leave fenced reserves they enter human-dominated landscapes where they face strong persecution and livestock predation incurs high costs. The factors driving packs to leave managed reserves are poorly understood, thus, to effectively manage wild dogs in fenced systems, it is important to understand why they leave reserve boundaries. There are several hypotheses as to why wild dogs cross through reserve fences, including inter- and intra-specific competition, social behaviour, management, prey density and environmental variability. Using a long-term dataset comprising 32 resident packs across five reserves, we investigated the relative strength of these hypotheses on the probability of wild dogs exiting a fenced reserve. During the 14-year study period, we recorded 154 exit events. We found that the interaction of fence integrity and time since pack formation were the primary factors affecting the probability of a pack leaving a reserve. When fence integrity was poor, escape probability decreased with pack age likely due to the exploratory behaviour of new packs. When fence integrity was average, escape probability increased with pack age likely due to the fitness benefits of holding larger and more exclusive territories as packs age. When fence integrity was good, the probability of a pack escaping was very low (only 1% occurrence). The implications of this research suggest that the primary management consideration for reducing wild dog escapes from fenced reserves should be maintaining adequate reserve-wide fence integrity, rather than focusing on social structure or drivers of inter- and intra-specific competition.

African wild dogs (Lycaon pictus) from the Kruger National Park, South Africa are currently not inbred but have low genomic diversity

African wild dogs (Lycaon pictus) have undergone severe population reductions and are listed as endangered on the International Union for Conservation of Nature Red List. Small, isolated populations have the potential to suffer from threats to their genetic diversity that may impact species viability and future survival. This study provides the first set of population-wide genomic data to address conservation concerns for this endangered species. Whole genome sequencing data were generated for 71 free-ranging African wild dogs from the Kruger National Park (KNP), South Africa, and used to estimate important population genomic parameters. Genomic diversity metrics revealed that variation levels were low; however, this African wild dog population showed low levels of inbreeding. Very few first- and second-order relationships were observed in this cohort, with most relationships falling into the third-order or distant category. Patterns of homozygosity could have resulted from historical inbreeding or a loss in genome variation due to a population bottleneck. Although the results suggest that this stronghold African wild dog population maintains low levels of inbreeding, likely due to their cooperative breeding system, it may lead to a continuous population decline when a reduced number of suitable mates are available. Consequently, the low genomic variation may influence species viability over time. This study highlights the importance of assessing population genomic parameters to set conservation priorities. Future studies should include the investigation of the potential of this endangered species to adapt to environmental changes considering the low genomic diversity in this population.

Not just the Big Five: African ecotourists prefer parks brimming with bird diversity

AbstractEcotourism helps sustain protected areas (PAs) that in turn conserve Africa's declining fauna. Identifying ecotourist preferences and which species and landscapes benefit from ecotourism could therefore support African biodiversity conservation efforts. Due to historic associations with trophy hunting and subsequent ecotourism marketing efforts, ecotourist preferences have been thought to traditionally center around the ‘Big Five’: elephant, lion, buffalo, leopard, and rhinoceros. But these preferences may be evolving. Here, we ask two questions, one about the drivers and one about the consequences of ecotourism: (1) Which species and landscapes do ecotourists most prefer based on realized visitation data? And (2), differently, which species and landscapes benefit most from ecotourism? We gathered data on average annual tourist visits, the occurrence of nine mammals, bird species richness, forest cover, national wealth, local human population and accessibility for 164 Sub‐Saharan African PAs. To address our first question, we used a Bayesian multivariable model to identify whether bird and megafaunal diversity explain visits to PAs while controlling for other factors. To address our second question, we used Bayesian univariate models to analyze the relationships between park visitation and each species/landscape. We found that tourist preferences extend beyond the Big Five to include bird diversity. We also observed that ecotourism may be well suited to conserve bird diversity, lion, cheetah, black and white rhinoceros, African wild dog and giraffe species. Collectively, our results may help inform how to leverage ecotourism to conserve African fauna.

Interpack communication in African wild dogs at long-term shared marking sites

Scent marks deposited as semiochemical signals are a primary mode of communication for a broad range of mammal species. Such scent signals are often deposited at specific, frequently visited marking sites called latrines. Despite descriptions of widespread latrine use by numerous mammal species, detailed understanding of site visit rates and latrine function is lacking. Here we report for the first time a quantitative assessment of scent-marking behaviours that represent interpack olfactory communication by African wild dogs, Lycaon pictus, at latrines visited by multiple resident neighbouring packs, hereafter called a ‘shared marking site’ (SMS). We show that multiple packs visited specific SMSs frequently and regularly throughout the year, with a notable decrease in visits during the 3-month denning season coinciding with a contraction in range size. In addition to resident neighbouring packs, dispersing individuals visited and scent-marked at SMSs, suggesting that latrines function at least in part as sites communicating information about residence and possibly reproductive status. Further detailed investigation of the relevance of latrine use to territorial behaviour, ranging, habitat use and dispersal in this species is required, particularly as it may have direct applied conservation implications for this wide-ranging but territorial endangered species.

Habitat use of and threats to African large carnivores in a mixed-uselandscape.

Large carnivores increasingly inhabit human-affected landscapes, which exhibit heterogeneity in biotic resources, anthropogenic pressures, and management strategies. Understanding large carnivore habitat use in these systems is critical for their conservation, as is the evaluation of competing management approaches and the impacts of significant land-use changes. We used occupancy modeling to investigate habitat use of an intact eastern African large carnivore guild across the 45,000 km2 Ruaha-Rungwa landscape in south-central Tanzania. We determined the relative impact on five large carnivore species of biotic, anthropogenic, and management factors at the scales of home range selection and short-term use within home ranges. We also specifically tested the effect of abandonment of trophy hunting areas on large carnivore occurrence. Patterns of habitat use differed among species. Lions (Panthera leo) appeared affected by top-down limitation, as their occurrence was significantly negatively associated with illegal human activity (β = -0.63 [SE 0.28]). African wild dogs (Lycaon pictus), instead, were limited by biotic features; the species was negatively associated with riverine areas of high sympatric predator density (β = -1.00 [SE 0.43]) and used less-productive habitats. Spotted hyaena (Crocuta crocuta) and leopard (Panthera pardus) persisted in more disturbed areas and across habitat types. Large carnivore occurrence was not affected by whether an area was used for photographic or trophy hunting tourism; regular law enforcement was instead a better predictor of occurrence. All species fared better in actively managed hunting areas than those that had been abandoned by operators. Overall, our findings highlight the divergent habitat requirements within large carnivore guilds and the importance of adopting an integrated approach to large carnivore conservation planning in modern systems. We also identified a novel threat to African conservation areas in the form of decreased management investments associated with the abandonment of trophy hunting areas.

Generalization of threats attributed to large carnivores in areas of high human-wildlife conflict.

Fear-induced generalization of threats to noninimical stimuli is a behavioral tendency of humans to minimize exposure to potential threats. In human-carnivore conflict zones, people often generalize their fear of predation by obligate carnivores to nonobligate carnivores despite differences in species' predation rates. We investigated the effect of a perceived threat of large obligate carnivores to livestock on tolerance and perception of striped hyena (Hyaena hyaena) in an area of high human-carnivore conflict. We surveyed 197 households through asemistructured questionnaire to determine people's perception and tolerance of striped hyenas in Sathyamangalam and Mudumalai Tiger Reserves after identification of the current distribution range of hyena determined through camera trap and sign surveys. Through the random forest algorithm, we modeled the level of tolerance of striped hyena as a function of loss of livestock to predation and from disease, the perceived threat of predation by hyena, and other socioeconomic attributes. Animal husbandry was a major source of income but was severely affected by livestock loss due to predation and disease. Sixty-nine percent of people were uncertain about predatory behavior of hyena; out of that, 23% reported a negative conservation attitude. Only 6 instances of hyena depredation on livestock and 2 on dogs were reported. Our model confirmed that economic instability associated with increased loss to predation and disease, livestock dependency, and a decrease in family annual income negatively affected people's tolerance of hyena. Perceptual uncertainty related to predatory behavior of hyena also negatively affected people's tolerance. In our study area, economic instability and perceptual uncertainty led to generalization of fear of large carnivores to a nonobligate predator. Such generalization may affect the attitude of people toward many other species. Understanding the role of economic instability and perceptual uncertainty should facilitate conservation of species, such as the hyena, that are vulnerable to false generalization.

Special Feature: Linking capture-recapture and movement.

Special Feature: Linking capture-recapture and movement.

The relative role of intrinsic and extrinsic drivers in regulating population change and survival of African wild dogs (Lycaon pictus)

The relative role of intrinsic and extrinsic drivers in regulating population change and survival of African wild dogs (Lycaon pictus)

Long-term, climate-driven phenological shift in a tropical large carnivore

Understanding the degree to which animals are shifting their phenology to track optimal conditions as the climate changes is essential to predicting ecological responses to global change. Species at low latitudes or high trophic levels are theoretically expected to exhibit weaker phenological responses than other species, but limited research on tropical systems or on top predators impedes insight into the contexts in which these predictions are upheld. Moreover, a lack of phenological studies on top predators limits understanding of how climate change impacts propagate through entire ecosystems. Using a 30-y dataset on endangered African wild dogs (Lycaon pictus), we examined changes in reproductive phenology and temperatures during birthing and denning over time, as well as potential fitness consequences of these changes. We hypothesized that their phenology would shift to track a stable thermal range over time. Data from 60 packs and 141 unique pack-years revealed that wild dogs have delayed parturition by 7 days per decade on average in response to long-term warming. This shift has led to temperatures on birthing dates remaining relatively stable but, contrary to expectation, has led to increased temperatures during denning periods. Increased denning temperatures were associated with reduced reproductive success, suggesting that a continued phenological shift in the species may become maladaptive. Such results indicate that climate-driven shifts could be more widespread in upper trophic levels than previously appreciated, and they extend theoretical understanding of the species traits and environmental contexts in which large phenological shifts can be expected to occur as the climate changes.

Predicting potential distributions of large carnivores in Kenya: An occupancy study to guide conservation

AbstractAimSpecies‐specific conservation strategies are frequently formulated based on species distribution maps, which are challenging to produce, especially at large spatial scales. Our aim was to use a novel empirical approach to predict the national distribution for all six large carnivore species found in Kenya to guide conservation and management decisions by identifying knowledge and conservation gaps.LocationKenya.MethodsWe collected data on carnivore presence and absence through questionnaire and sightings‐based surveys and analysed the combined data set using single‐season false‐positive occupancy models, which account for imperfect detections and false positives. To predict potential distributions and inform conservation strategies, we used the occupancy outputs to make predictions for unsampled areas and create occupancy‐based distribution maps where ψ > 0.50, to (1) quantify differences with IUCN Red List range maps, (2) quantify overlap with wildlife areas and (3) identify areas of high carnivore richness.ResultsLarge carnivore occupancy was associated with land conversion, habitat and prey availability. Our results suggest that all six species are widely distributed across Kenya and reveal substantial differences to distribution maps compiled by the IUCN Red List. More specifically, our occupancy‐based distribution maps predict much larger distribution for African wild dog (5.09X), lion (4.77X) and leopard (1.46X), similar distribution for cheetah, and smaller distribution for spotted hyaena (0.84X) and striped hyaena (0.65X). For all large carnivores, the vast majority (~80%) of their predicted distribution falls outside wildlife areas and northern Kenya is predicted to have the highest large carnivore richness.Main conclusionsOur results are encouraging as large carnivores may be widely distributed across Kenya, in some cases potentially more so than previously acknowledged. However, much of this range lies outside wildlife areas and represent areas of concern both for conservation and human livelihoods illustrating the challenges of conserving large carnivores across their range.

African Wild Dog Reproductive Capabilities Revisited: Successfully Raising Three Litters in Less than 14 Months is Possible

African wild dogs (Lycaon pictus) are obligate cooperative breeders and are generally considered mono-oestrus. As such, the birth of two litters within the same year rarely occurs, except for when pups from the initial litter are lost soon after birth. We report on a rare occurrence where a wild dog female (Vee) produced three litters of pups within a 13-month, 2-week period from March 2015 to June 2016, with surviving pups from each litter. Data on breeding females from wild dog packs in the study area (Savé Valley Conservancy, Zimbabwe) were used to identify whether any predictor variables (e.g. environmental or pack dynamics) could have influenced this unusual occurrence. The period over which the high number of litters were born had high prey densities and there was some evidence that it was associated with lower temperatures. High impala (Aepyceros melampus) densities during 2015 was likely to have been advantageous for the packs' hunting behaviours, while lower temperatures have been shown to increase the percentage of the day that is cool enough for wild dogs to hunt. Pack size during this period was higher in the pack that produced multiple litters (by the same female) than for other packs in the study site, which supports existing evidence that larger packs are able to produce more pups. Our results suggest that either 1) under ideal environmental and social conditions African wild dog females are capable of producing multiple litters throughout the year or that 2) this occurrence was an anomaly unique to Vee and her physiology.

Hierarchy of fear: experimentally testing ungulate reactions to lion, African wild dog and cheetah

AbstractExperiments have begun demonstrating that the fear (antipredator behavioral responses) large carnivores inspire in ungulates can shape ecosystem structure and function. Most such experiments have focused on the impacts of either just one large carnivore, or all as a whole, rather than the different impacts different large carnivores may have in intact multi-predator-prey systems. Experimentally testing the relative fearfulness ungulates demonstrate toward different large carnivores is a necessary first step in addressing these likely differing impacts. We tested the fearfulness ungulates demonstrated to playbacks of lion (Panthera leo), African wild dog (Lycaon pictus), cheetah (Acinonyx jubatus) or non-predator control (bird) vocalizations, in Greater Kruger National Park, South Africa. Ungulates ran most to lions, then wild dogs, and then cheetahs, demonstrating a very clear hierarchy of fear. Those that did not run looked toward the sound more on hearing large carnivores than controls, looking most on hearing lions. Notably, prey species-specific population level kill rates by each predator did not predict the patterns observed. Our results demonstrate that different large carnivores inspire different levels of fear in their ungulate prey, pointing to differing community-level impacts, which we discuss in relation to the ongoing worldwide decline and loss of large carnivores.

African Wild Dogs (Lycaon pictus) Show Adaptations to Sociality and Hypercarnivory in Their Cranial Musculature

African wild dogs (Lycaon pictus) are highly social canids that live in large, hierarchical packs and engage in coordinated hunts. Recent research has suggested that enlarged muscles associated with expressive movement of the eyes and eyebrows may have evolved in domestic dogs (Canis familiaris) to facilitate interspecies communication with their human owners. In L. pictus, communication is reported to occur predominantly through vocalization with reduced reliance on facial expressions; however, the mimic muscles in L. pictus have never been described and evaluated. L. pictus is also hypercarnivorous with the highest documented bite force quotient of any mammalian carnivore. It has large, mobile ears, which enhance its auditory capabilities while hunting and assist with thermoregulation.We performed detailed dissections of the muscles of facial expression, mastication, and auricular movement in an adult male L. pictus,and conducted diffusible iodine‐based contrast‐enhanced computed tomographic (diceCT) scans of the head. Musculus levator anguli oculi medialis (LAOM) and retractor anguli oculi lateralis (RAOL), muscles of hypothesized importance in domestic dog‐human non‐verbal communication, are enlarged in L. pictus, suggesting that ocular expressions represent a significant component of communication. LAOM exhibits an intricate relationship with adjacent orbital musculature including partial fusion along its borders with mm. orbicularis oculi and frontalis. Muscles that draw the angles of the mouth caudally (e.g., m. zygomaticus major) are expanded. Numerous ramifying branches of CN VII and CN V2 course across the face to provide extensive sensory and motor innervation. These findings indicate that facial expression musculature of African wild dogs is well‐equipped for non‐verbal communication and that the same adaptations argued to facilitate communication between domestic dogs and humans may also facilitate intraspecific communication in L. pictus.Muscles of mastication are especially enlarged in L. pictus, with multiple bellies of mm. masseter and temporalis separated by deep layers of thick intermuscular fascia and with expanded insertions onto the mandible. Musculus digastricus is composed of a single, large belly without intervening tendon, and it receives its innervation exclusively from CN V3. These enlargements reflect increased masticatory capabilities in L. pictus, which enable its powerful bite force and hypercarnivorous diet. Auricular muscles are also well‐developed, supporting greater leverage and fine manipulation of its large, mobile ears. Musculus frontoscutularis is well‐developed and distinctly separable from m. frontalis, suggesting greater leverage of the auricle via attachments to the scutiform cartilage. The intrinsic ear muscles differ in pattern and orientation from all other published canids, demonstrating unique muscular control over rotation and fine manipulation of the auricle. Taken together, these morphological patterns illustrate that specific adaptations in the cranial musculature of L. pictus facilitate its ecological habits.

Genome-wide investigations reveal the population structure and selection signatures of Nigerian cattle adaptation in the sub-Saharan tropics

BackgroundCattle are considered to be the most desirable livestock by small scale farmers. In Africa, although comprehensive genomic studies have been carried out on cattle, the genetic variations in indigenous cattle from Nigeria have not been fully explored. In this study, genome-wide analysis based on genotyping-by-sequencing (GBS) of 193 Nigerian cattle was used to reveal new insights on the history of West African cattle and their adaptation to the tropical African environment, particularly in sub-Saharan region. ResultsThe GBS data were evaluated against whole-genome sequencing (WGS) data and high rate of variant concordance between the two platforms was evident with high correlated genetic distance matrices genotyped by both methods suggestive of the reliability of GBS applicability in population genetics. The genetic structure of Nigerian cattle was observed to be homogenous and unique from other African cattle populations. Selection analysis for the genomic regions harboring imprints of adaptation revealed genes associated with immune responses, growth and reproduction, efficiency of feeds utilization, and heat tolerance. Our findings depict potential convergent adaptation between African cattle, dogs and humans with adaptive genes SPRY2 and ITGB1BP1 possibly involved in common physiological activities.ConclusionThe study presents unique genetic patterns of Nigerian cattle which provide new insights on the history of cattle in West Africa based on their population structure and the possibility of parallel adaptation between African cattle, dogs and humans in Africa which require further investigations.

Lycaon pictus (Carnivora: Canidae)

Abstract Lycaon pictus (Temminck, 1820), the African wild dog, is a moderately sized carnivore with dog-like appearance and irregularly mottled black, yellow-brown, and white pelage. It has a head–body length of 76–112 cm, tail length of 30–41 cm, shoulder height of 61–78 cm, and body weight of 17–36 kg. Lycaon pictus has four toes on each foot, differentiating it from other canids; is the only extant species within the genus with no subspecies; and is unlikely to be confused with any other canid. Lycaon pictus was once widespread throughout sub-Saharan Africa inhabiting nearly all environments and now inhabits grasslands, montane savanna, and open woodlands. Lycaon pictus is recognized as “Endangered” (EN) by the U.S. Fish and Wildlife Service and the International Union for Conservation of Nature.

African wild dog movements show contrasting responses to long and short term risk of encountering lions: analysis using dynamic Brownian bridge movement models

BackgroundPrey depletion is a threat to the world’s large carnivores, and is likely to affect subordinate competitors within the large carnivore guild disproportionately. African lions limit African wild dog populations through interference competition and intraguild predation. When lion density is reduced as a result of prey depletion, wild dogs are not competitively released, and their population density remains low. Research examining distributions has demonstrated spatial avoidance of lions by wild dogs, but the effects of lions on patterns of movement have not been tested. Movement is one of the most energetically costly activities for many species and is particularly costly for cursorial hunters like wild dogs. Therefore, testing how top-down, bottom-up, and anthropogenic variables affect movement patterns can provide insight into mechanisms that limit wild dogs (and other subordinate competitors) in resource-depleted ecosystems.MethodsWe measured movement rates using the motion variance from dynamic Brownian Bridge Movement Models (dBBMMs) fit to data from GPS-collared wild dogs, then used a generalized linear model to test for effects on movement of predation risk from lions, predictors of prey density, and anthropogenic and seasonal variables.ResultsWild dogs proactively reduced movement in areas with high lion density, but reactively increased movement when lions were immediately nearby. Predictors of prey density had consistently weaker effects on movement than lions did, but movements were reduced in the wet season and when dependent offspring were present.ConclusionWild dogs alter their patterns of movement in response to lions in ways that are likely to have important energetic consequences. Our results support the recent suggestion that competitive limitation of wild dogs by lions remains strong in ecosystems where lion and wild dog densities are both low as a result of anthropogenic prey depletion. Our results reinforce an emerging pattern that movements often show contrasting responses to long-term and short-term variation in predation risk.

A description of a new discovery: African wild dog packs communicate with other packs by posting scent-mark messages at a shared marking site

A description of a new discovery: African wild dog packs communicate with other packs by posting scent-mark messages at a shared marking site