Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
1.
PeerJ ; 12: e17767, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39056054

RESUMEN

Group-living animals engage in coordinated vocalizations to depart from a location as a group, and often, to come to a consensus about the direction of movement. Here, we document for the first time, the use of coordinated vocalizations, the "let's go" rumble, in wild male African elephant group departures from a waterhole. We recorded vocalizations and collected behavioral data as known individuals engaged in these vocal bouts during June-July field seasons in 2005, 2007, 2011, and 2017 at Mushara waterhole within Etosha National Park, Namibia. During departure events, we documented which individuals were involved in the calls, the signature structure of each individual's calls, as well as the ordering of callers, the social status of the callers, and those who initiated departure. The "let's go" rumble was previously described in tight-knit family groups to keep the family together during coordinated departures. Male elephants are described as living in loose social groups, making this finding particularly striking. We found that this vocal coordination occurs in groups of closely associated, highly bonded individuals and rarely occurs between looser associates. The three individuals most likely to initiate the "let's go" rumble bouts were all highly socially integrated, and one of these individuals was also the most dominant overall. This finding suggests that more socially integrated individuals might be more likely to initiate, or lead, a close group of associates in the context of leaving the waterhole, just as a high-ranking female would do in a family group. The fact that many individuals were involved in the vocal bouts, and that departure periods could be shorter, longer, or the same amount of time as pre-departure periods, all suggest that there is consensus with regard to the act of leaving, even though the event was triggered by a lead individual.


Asunto(s)
Elefantes , Liderazgo , Conducta Social , Vocalización Animal , Masculino , Animales , Vocalización Animal/fisiología , Elefantes/fisiología , Namibia , Consenso
2.
PeerJ ; 12: e17535, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38854797

RESUMEN

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.


Asunto(s)
Bienestar del Animal , Elefantes , Animales , Elefantes/fisiología , Sudáfrica , Conducta Animal/fisiología , Femenino , Masculino , Animales Salvajes , Estaciones del Año , Conservación de los Recursos Naturales/métodos
3.
Ecol Evol ; 14(6): e11574, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38919648

RESUMEN

To conserve wide-ranging species in degraded landscapes, it is essential to understand how the behavior of animals changes in relation to the degree and composition of modification. Evidence suggests that large inter-individual variation exists in the propensity for use of degraded areas and may be driven by both behavioral and landscape factors. The use of cultivated lands by wildlife is of particular interest, given the importance of reducing human-wildlife conflicts and understanding how such areas can function as biodiversity buffers. African elephant space use can be highly influenced by human activity and the degree to which individuals crop-raid. We analyzed GPS data from 56 free-ranging elephants in the Serengeti-Mara Ecosystem using resource selection functions (RSFs) to assess how crop use may drive patterns of resource selection and space use within a population. We quantified drivers of similarity in resource selection across individuals using proximity analysis of individual RSF coefficients derived from random forest models. We found wide variation in RSF coefficient values between individuals indicating strongly differentiated resource selection strategies. Proximity assessment indicated the degree of crop use in the dry season, individual repeatability, and time spent in unprotected areas drove similarity in resource selection patterns. Crop selection was also spatially structured in relation to agricultural fragmentation. In areas with low fragmentation, elephants spent less time in crops and selected most strongly for crops further from protected area boundaries, but in areas of high fragmentation, elephants spent twice as much time in crops and selected most strongly for crops closer to the protected area boundary. Our results highlight how individual differences and landscape structure can shape use of agricultural landscapes. We discuss our findings in respect to the conservation challenges of human-elephant conflict and incorporating behavioral variation into human-wildlife coexistence efforts.

4.
Anim Genet ; 55(4): 621-643, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38923598

RESUMEN

The African savanna elephant (Loxodonta africana) is the largest terrestrial animal on Earth and is found primarily in Southern and Eastern Africa. It is a hindgut, colonic fermenter and subsists on a diet of raw plant materials found in its grazing area. In this study the bacterial, archaeal and fungal populations of seven African savanna elephant fecal metagenomes were first characterized using amplicon sequencing. On the genus level it was observed that the p-1088-a5 gut group in the bacteriome, Methanocorpusulum and Methanobrevibacter in the archaeome and Alternaria, Aurobasidium, Didymella and Preussia in the mycome, predominated. Subsequently, metagenomic shotgun sequencing was employed to identify possible functional pathways and carbohydrate-active enzymes (CAZymes). Carbohydrate catabolic pathways represented the main degradation pathways, and the fecal metagenome was enriched in the glycohydroside (GH) class of CAZymes. Additionally, the top GH families identified - GH43, GH2, GH13 and GH3 - are known to be associated with cellulytic, hemicellulytic and pectolytic activities. Finally, the CAZymes families identified in the African savanna elephant were compared with those found in the Asian elephant and it was demonstrated that there is a unique repository of CAZymes that could be leveraged in the biotechnological context such as the degradation of lignocellulose for the production of second-generation biofuels and energy.


Asunto(s)
Bacterias , Elefantes , Heces , Microbioma Gastrointestinal , Metagenoma , Animales , Elefantes/genética , Elefantes/microbiología , Heces/microbiología , Bacterias/genética , Bacterias/clasificación , Bacterias/aislamiento & purificación , Archaea/genética , Archaea/clasificación , Metagenómica , Hongos/genética , Hongos/clasificación
5.
Am J Vet Res ; 85(7)2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38684186

RESUMEN

OBJECTIVE: To evaluate the pharmacokinetics of famciclovir and its metabolite penciclovir following a single dose administered orally and rectally in African elephants (Loxodonta africana). ANIMALS: 15 African elephants (6 males and 9 females) of various ages. METHODS: Famciclovir (15 mg/kg) was administered orally or per rectum once, with at least a three-week washout period between administrations. Blood was collected at 13 different timepoints per administration for 6 elephants, occurring between February and March 2020. An additional 9 elephants were sampled at variable timepoints per administration utilizing a sparse sampling design between July 2020 and January 2021. Plasma famciclovir and penciclovir levels were measured via HPLC and fluorescence detection. Pharmacokinetic analysis was completed in the summer of 2021 using noncompartmental analysis and nonlinear mixed-effects modeling. RESULTS: Famciclovir was not detected in any sample, suggesting complete metabolism. Key pharmacokinetic parameters for penciclovir following oral administration were time to maximum concentration (tmax; 2.12 hours), area under the concentration-versus-time curve (AUC; 33.93 µg·h/mL), maximum observed concentration (Cmax; 3.73 µg/mL), and absorption half-life (t1/2; 0.65 hours). Following rectal administration, the values were: tmax, 0.65 hours; AUC, 15.62 µg·h/mL; Cmax, 2.52 µg/mL; and absorption t1/2, 0.13 hours. CONCLUSIONS: Famciclovir was rapidly metabolized to penciclovir. Oral administration resulted in slower absorption but higher maximum plasma concentration and higher AUC compared to rectal administration. CLINICAL RELEVANCE: African elephants administered famciclovir via oral and rectal routes resulted in measurable serum penciclovir, and these findings may be utilized by clinicians treating viral infections in this species.


Asunto(s)
Aciclovir , Administración Rectal , Antivirales , Elefantes , Famciclovir , Animales , Famciclovir/farmacocinética , Famciclovir/administración & dosificación , Elefantes/sangre , Administración Oral , Masculino , Antivirales/farmacocinética , Antivirales/administración & dosificación , Antivirales/sangre , Femenino , Aciclovir/farmacocinética , Aciclovir/administración & dosificación , Aciclovir/sangre , Aciclovir/análogos & derivados , Guanina/análogos & derivados , Guanina/farmacocinética , Guanina/administración & dosificación , Área Bajo la Curva , Semivida
6.
Forensic Sci Int Genet ; 70: 103027, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38422900

RESUMEN

Currently, the global elephant population has significantly declined due to the poaching of elephants for their ivory, and this is the reason why elephants are listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, Thailand allows the legal trade of ivory from registered, domesticated Asian elephants, leading to the smuggling of African elephant ivory, and passing them off as Asian elephant ivory. Therefore, this research aims to develop and validate a portable strip test to discriminate between Asian and African elephants DNA, using Recombinase Polymerase Amplification (RPA) and Lateral Flow Dipstick assay (LFD) according to international standards. The results showed that the strip test can be successfully developed with 100% accuracy (n = 105). This kit is specific to elephants, has a detection limit of 0.125 ng of DNA, and can effectively discriminate a variety of elephant ivory, including raw ivory, ivory products, and aged ivory over 25 years old, which had been damaged by fire, all with 100% accuracy (n = 117). Additionally, the developed strip test is designed to be portable and cost-effective. It does not require expensive laboratory equipment and provides a faster analysis process compared with conventional PCR-based methods. This will expedite the legal process and enforcement of laws related to elephant conservation, reducing the opportunities for illegal activities, and enabling timely prosecution under relevant wildlife conservation laws in Thailand and internationally.


Asunto(s)
Elefantes , Animales , Elefantes/genética , Conservación de los Recursos Naturales , Comercio , Internacionalidad , ADN/genética
7.
Vet Med Sci ; 10(1): e1331, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37990940

RESUMEN

Maternal nutrition and the uterine environment can influence placental development in mammals, leading to the birth of abnormal infants who often experience difficulties in independent standing. This article documents an adolescent female African elephant (Loxodonta africana) giving birth to an African elephant calf with a shoulder height below the mean, and its inability to stand for the first 10 h after birth, a time span that significantly exceeds the average duration for independent standing. Through the implementation of assisted feeding and assisted standing measures, the calf eventually achieved independent standing and nursing from its mother after 27 h and subsequent catch-up growth at 5 months of age. This study presents the first case report on the growth parameters during pregnancy of an adolescent African elephant, the birth and care (feeding, assisted standing) of a small African elephant calf with the inability to stand alone and nurse independently for several hours, highlighting pregnancy may influence the growth of cows during their ongoing growth and development phase, the calf's survival and subsequent catch-up growth at 5 months of age. These findings offer valuable insights into the care of abnormal African elephant calves.


Asunto(s)
Elefantes , Embarazo , Animales , Femenino , Bovinos , Placenta
8.
Animals (Basel) ; 13(14)2023 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-37508130

RESUMEN

Following population declines of the African savanna elephant (Loxodonta africana) across the African continent, the establishment of primary cell lines of endangered wildlife species is paramount for the preservation of their genetic resources. In addition, it allows molecular and functional studies on the cancer suppression mechanisms of elephants, which have previously been linked to a redundancy of tumor suppressor gene TP53. This methodology describes the establishment of primary elephant dermal fibroblast (EDF) cell lines from skin punch biopsy samples (diameter: ±4 mm) of African savanna elephants (n = 4, 14-35 years). The applied tissue collection technique is minimally invasive and paves the way for future remote biopsy darting. On average, the first explant outgrowth was observed after 15.75 ± 6.30 days. The average doubling time (Td) was 93.02 ± 16.94 h and 52.39 ± 0.46 h at passage 1 and 4, respectively. Metaphase spreads confirmed the diploid number of 56 chromosomes. The successful establishment of EDF cell lines allows for future elephant cell characterization studies and for research on the cancer resistance mechanisms of elephants, which can be harnessed for human cancer prevention and treatment and contributes to the conservation of their genetic material.

9.
Animals (Basel) ; 13(12)2023 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-37370449

RESUMEN

Cytochrome P450 is an important enzyme that metabolizes a variety of chemicals, including exogenous substances, such as drugs and environmental chemicals, and endogenous substances, such as steroids, fatty acids, and cholesterol. Some CYPs show interspecific differences in terms of genetic variation. As little is known about the mechanisms of elephant metabolism, we carried out a comparative genomic and phylogenetic analysis of CYP in elephants. Our results suggest that elephant CYP genes have undergone independent duplication, particularly in the CYP2A, CYP2C, and CYP3A genes, a unique cluster specific to elephant species. However, while CYP2E and CYP4A were conserved in other Afrotheria taxa, their decay in elephants resulted in genetic dysfunction (pseudogene). These findings outline several remarkable characteristics of elephant CYP1-4 genes and provide new insights into elephant xenobiotic metabolism. Further functional investigations are necessary to characterize elephant CYP, including expression patterns and interactions with drugs and sensitivities to other chemicals.

10.
Molecules ; 28(5)2023 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-36903269

RESUMEN

The milk of mammals is a complex fluid mixture of various proteins, minerals, lipids, and other micronutrients that play a critical role in providing nutrition and immunity to newborns. Casein proteins together with calcium phosphate form large colloidal particles, called casein micelles. Caseins and their micelles have received great scientific interest, but their versatility and role in the functional and nutritional properties of milk from different animal species are not fully understood. Caseins belong to a class of proteins that exhibit open and flexible conformations. Here, we discuss the key features that maintain the structures of the protein sequences in four selected animal species: cow, camel, human, and African elephant. The primary sequences of these proteins and their posttranslational modifications (phosphorylation and glycosylation) that determine their secondary structures have distinctively evolved in these different animal species, leading to differences in their structural, functional, and nutritional properties. The variability in the structures of milk caseins influence the properties of their dairy products, such as cheese and yogurt, as well as their digestibility and allergic properties. Such differences are beneficial to the development of different functionally improved casein molecules with variable biological and industrial utilities.


Asunto(s)
Queso , Micelas , Recién Nacido , Animales , Femenino , Bovinos , Humanos , Leche/química , Caseínas/química , Secuencia de Aminoácidos , Proteínas de la Leche/análisis , Mamíferos
11.
J Wildl Dis ; 59(1): 128-137, 2023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-36584337

RESUMEN

Elephant endotheliotropic herpesvirus (EEHV) infection can cause acute, often fatal, EEHV hemorrhagic disease in free-ranging and human-managed Asian elephants (Elephas maximus) and human-managed African elephants (Loxodonta africana). However, significant knowledge gaps exist pertaining to the presence of EEHV in free-ranging African elephant populations. We retrospectively screened 142 opportunistically collected samples (blood, n=98; bronchoalveolar lavage (BAL) fluid, n=21; trunk wash (TW) fluid, n=23) obtained between 2010 and 2020 from 98 free-ranging African elephants in the Kruger National Park, South Africa, for the presence of different EEHVs, as well as determining the real-time quantitative PCR positivity rate in this population. With the use of validated, previously published DNA extraction and real-time quantitative PCR protocols provided by the National Elephant Herpesvirus Laboratory (Washington, DC, USA), EEHV was detected in nine male African elephants from samples collected in 2011 (n=1), 2013 (n=1), 2018 (n=2), 2019 (n=4), and 2020 (n=1). Viral detection was more common in respiratory compared with blood samples. Six elephants tested positive for EEHV2 subtype (blood, n=2; BAL, n=3; TW, n=2), including one individual that tested positive on matched respiratory samples (BAL and TW). Four elephants tested positive for EEHV3-4-7 (blood, n=1; BAL, n=2; TW, n=1), whereas EEHV6 was not detected in any of the study animals. One elephant tested positive for both EEHV2 and EEHV3-4-7 in the same BAL sample. Even though the levels of viremia varied between 158 and 1,292 viral genome equivalents/mL blood and viral shedding of EEHV2 and EEHV3-4-7 was detected in respiratory samples, no clinical signs were observed in these apparently healthy elephants. These findings are consistent with reports of asymptomatic EEHV infection in human-managed African elephants.


Asunto(s)
Elefantes , Infecciones por Herpesviridae , Herpesviridae , Humanos , Masculino , Animales , Sudáfrica , Parques Recreativos , Estudios Retrospectivos , Herpesviridae/genética , Infecciones por Herpesviridae/epidemiología , Infecciones por Herpesviridae/veterinaria
12.
Conserv Physiol ; 10(1): coac053, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35919453

RESUMEN

Orphans of several species suffer social and physiological consequences such as receiving more aggression from conspecifics and lower survival. One physiological consequence of orphaning, stunted growth, has been identified in both humans and chimpanzees, but has not been assessed in a non-primate species. Here, we tested whether wild African elephant orphans show evidence of stunted growth. We measured individually known female elephants in the Samburu and Buffalo Springs National Reserves of Kenya, with a rangefinder capable of calculating height, to estimate a von Bertalanffy growth curve for female elephants of the study population. We then compared measurements of known orphans and non-orphans of various ages, using a Bayesian analysis to assess variation around the derived growth curve. We found that orphans are shorter for their age than non-orphans. However, results suggest orphans may partially compensate for stunting through later growth, as orphans who had spent a longer time without their mother had heights more similar to non-orphans. More age mates in an individual's family were associated with taller height, suggesting social support from peers may contribute to increased growth. Conversely, more adult females in an individual's family were associated with shorter height, suggesting within-group competition for resources with older individuals may reduce juvenile growth. Finally, we found a counterintuitive result that less rainfall in the first 6 years of life was correlated with taller height, potentially reflecting the unavoidable bias of measuring individuals who were fit enough to survive conditions of low rainfall as young calves. Reduced growth of individuals has been shown to reduce survival and reproduction in other species. As such, stunting in wildlife orphans may negatively affect fitness and represents an indirect effect of ivory poaching on African elephants.

13.
Animals (Basel) ; 12(9)2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35565588

RESUMEN

Driven by reproductive motives, male African elephants (Loxodonta africana) in musth often expand their home ranges to locate estrous females. This extended range, coupled with heightened aggression often observed in musth males, can be particularly problematic in regions where human-modified landscapes and elephant territories increasingly overlap. Several mitigation tools have been tested to resolve a wide range of human-elephant conflicts with varying degrees of success due to geographical disparities and habituation. We present findings on the potential application of estrous call playbacks in manipulating the behavior and movement of male elephants non-invasively, particularly mature musth adults and younger post-dispersal males, in Etosha National Park. Estrous vocalizations were presented across 26 experimental trials to mature musth adults (n = 5), mature non-musth adults (n = 6), and non-musth males belonging to younger, post-dispersal age classes (n = 8), with behavioral responses scored on a gradient scale from 0-1. Both mature musth adults and younger non-musth elephants were significantly more likely to respond with the highest intensity by approaching the acoustic source compared to mature non-musth adults that avoided the call. However, younger males tested in the presence of an older, higher-ranking male tended to react with a lower intensity than those tested alone. This result likely demonstrates the influence of social hierarchy and associations on male elephant behavior. We also observed a significant increase in physiological response, measured by defecation rate, across all male groups in response to the estrous call playbacks. Our findings suggest that using estrous calls as acoustic deterrents may effectively and non-invasively aid in reducing tension at the human-elephant interface, depending on the age, social context, and reproductive status of the male elephant.

14.
J Anim Ecol ; 91(8): 1693-1706, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35535017

RESUMEN

Individual variation in habitat selection and movement behaviour is receiving growing attention, but primarily with respect to characterizing behaviours in different contexts as opposed to decomposing structure in behaviour within populations. This focus may be limiting advances in understanding the diversity of individual behaviour and its influence on population organization. We propose a framework for characterizing variation in space-use behaviour with the aim of advancing interpretation of its form and function. Using outputs from integrated step-selection analyses of 20 years of telemetry data from African elephants Loxodonta Africana, we developed four metrics characterizing differentiation in resource selection behaviour within a population (specialization [magnitude of the response independent of direction], heterogeneity [inter-individual variation], consistency [temporal shift in response] and reversal [frequency of directional changes in the response]). We contrasted insight from the developed metrics relative to the mean population response using an example focused on two covariates. We then expanded this contrast by evaluating if the metrics identify structurally important information on seasonal shifts in resource selection behaviours in addition to that provided by mean selection coefficients through principal component analyses (PCAs) and a random forest classification. The simplified example highlighted that for some covariates focusing on the population average failed to capture complex individual variation in behaviours. The PCAs revealed that the developed metrics provided additional information in explaining the patterns in elephant selection beyond that offered by population average covariate values. For elephants, specialization and heterogeneity were informative, with specialization often being a better descriptor of differences in seasonal resource selection behaviour than population average responses. Summarizing these metrics spatially and temporally, we illustrate how these metrics can provide insights on overlooked aspects of animal behaviour. Our work offers a new approach in how we conceptualize variation in space-use behaviour (i.e. habitat selection and movement) by providing ways of encapsulating variation that enables diagnoses of the drivers of individual-level variability in a population. The developed metrics explicitly distil how variation in a behaviour is structured among individuals and over time which could facilitate comparative work across time, populations or strata within populations.


Asunto(s)
Benchmarking , Elefantes , Animales , Conducta Animal , Ecosistema , Conducta Espacial
15.
Metabolites ; 12(5)2022 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-35629905

RESUMEN

We used nuclear magnetic spectroscopy (NMR) to evaluate the metabolomics of heparinized whole blood drawn from six African savanna elephants (Loxodonta africana) maintained on a well characterized diet. Whole blood samples obtained under behavioral restraint, then quickly frozen in liquid nitrogen, were stored at -80 °C until analysis. Frozen samples were thawed under controlled conditions and extracted with methanol and chloroform to separate the polar and non-polar metabolites. We identified 18 polar metabolites and 14 non-polar lipids using one-dimensional (1D) and two-dimensional (2D) NMR spectra. Despite unexpected rouleaux formation in the thawed frozen samples, spectra were consistent among animals and did not vary dramatically with age or the sex of the animal.

16.
J Anim Ecol ; 91(1): 112-123, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34726278

RESUMEN

To conserve wide-ranging species in human-modified landscapes, it is essential to understand how animals selectively use or avoid cultivated areas. Use of agriculture leads to human-wildlife conflict, but evidence suggests that individuals may differ in their tendency to be involved in conflict. This is particularly relevant to wild elephant populations. We analysed GPS data of 66 free-ranging elephants in the Serengeti-Mara ecosystem to quantify their use of agriculture. We then examined factors influencing the level of agricultural use, individual change in use across years and differences in activity budgets associated with use. Using clustering methods, our data grouped into four agricultural use tactics: rare (<0.6% time in agriculture; 26% of population), sporadic (0.6%-3.8%; 34%), seasonal (3.9%-12.8%; 31%) and habitual (>12.8%; 9%). Sporadic and seasonal individuals represented two-thirds (67%) of recorded GPS fixes in agriculture, compared to 32% from habitual individuals. Increased agricultural use was associated with higher daily distance travelled and larger home range size, but not with age or sex. Individual tactic change was prevalent and the habitual tactic was maintained in consecutive years by only five elephants. Across tactics, individuals switched from diurnal to nocturnal activity during agricultural use, interpreted as representing similar risk perception of cultivated areas. Conversely, tactic choice appeared to be associated with differences in risk tolerance between individuals. Together, our results suggest that elephants are balancing the costs and benefits of crop usage at both fine (e.g. crop raid events) and long (e.g. yearly tactic change) temporal scales. The high proportion of sporadic and seasonal tactics also highlights the importance of mitigation strategies that address conflict arising from many animals, rather than targeted management of habitual crop raiders. Our approach can be applied to other species and systems to characterize individual variation in human resource use and inform mitigations for human-wildlife coexistence.


Asunto(s)
Elefantes , Agricultura , Animales , Animales Salvajes , Conservación de los Recursos Naturales/métodos , Ecosistema , Percepción
17.
Animals (Basel) ; 11(10)2021 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-34680009

RESUMEN

The introduction of elephants into new groups is necessary for breeding programmes. However, behavioural studies on the reactions of these animals at first encounters are missing. In the present study, female African elephants (Loxodonta africana) living in zoos were observed during unifications with unfamiliar elephants (introduction of two to one females and one to two females; n = 6) and reunifications with related elephants (two mother-daughter-pairs; n = 4) that were separated for 2 and 12 years, respectively. First encounters of the elephants were observed and recorded by scan sampling. The parameters measured were (a) signs of the characteristic Greeting Ceremony, (b) distance to the fence separating the elephants during first contact, and (c) time until trunks touched for the first time. The data were statistically analysed with SPSS. The results showed that related elephants performed a full Greeting Ceremony on reunifications. Unrelated elephants only expressed a minor greeting. During first encounters, related elephants predominantly showed affiliative behaviour (p = 0.001), whilst unrelated elephants expressed more agonistic behaviour (p = 0.001). The distance to the fence was significantly smaller for related elephants than for unrelated elephants (p = 0.038). first contact of trunks occurred on average after 3.00 s. in related elephants and 1026.25 s. in unrelated elephants. These findings indicate that related elephants recognise their kin after up to 12 years of separation, meet them with a full Greeting Ceremony during reunification, and seek contact to the related elephant, while unrelated elephants are hesitant during unifications with unfamiliar elephants and express more agonistic behaviour. The results testify that zoo elephants show the same species-specific social behaviour as their conspecifics in the wild. It also confirms the cognitive abilities of elephants and the significance of matrilines for breeding programmes.

18.
Curr Biol ; 31(18): 4156-4162.e5, 2021 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-34343478

RESUMEN

Prolonged maternal care is vital to the well-being of many long-lived mammals.1 The premature loss of maternal care, i.e., orphaning, can reduce offspring survival even after weaning is complete.2-5 However, ecologists have not explicitly assessed how orphaning impacts population growth. We examined the impact of orphaning on population growth in a free-ranging African elephant population, using 19 years of individual-based demographic monitoring data. We compared orphan and nonorphan survival, performed a sensitivity analysis to understand how population growth responds to the probability of being orphaned and orphan survival, and investigated how sensitivity to these orphan parameters changed with level of poaching. Orphans were found to have lower survival compared to nonorphaned age mates, and population growth rate was negatively correlated with orphaning probability and positively correlated with orphan survival. This demonstrates that, in addition to its direct effects, adult elephant death indirectly decreases population growth through orphaning. Population growth rate's sensitivity to orphan survival increased for the analysis parameterized using only data from years of more poaching, indicating orphan survival is more important for population growth as orphaning increases. We conclude that orphaning substantively decreases population growth for elephants and should not be overlooked when quantifying the impacts of poaching. Moreover, we conclude that population models characterizing systems with extensive parental care benefit from explicitly incorporating orphan stages and encourage research into quantifying effects of orphaning in other social mammals of conservation concern.


Asunto(s)
Elefantes , Animales , Conservación de los Recursos Naturales , Crimen , Dinámica Poblacional , Crecimiento Demográfico
19.
Animals (Basel) ; 11(3)2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33804098

RESUMEN

This study aimed to investigate how three groups of people of differing ages, and with differing knowledge of the species, perceived the emotional state of African elephants (Loxodonta africana) managed in captive and semi-captive environments. Fifteen video-clips of 18 elephants, observed during three different daily routines (release from and return to the night boma; interactions with visitors), were used for a free choice profiling assessment (FCP) and then analyzed with quantitative methods. A general Procrustes analysis identified two main descriptive dimensions of elephant behavioral expression explaining 27% and 19% of the variability in the children group, 19% and 23.7% in adults, and 21.8% and 17% in the expert group. All the descriptors the observers came up with showed a low level of correlation on the identified dimensions. All three observers' groups showed a degree of separation between captive and semi-captive management. Spearman analyses showed that stereotypic "trunk swirling" behavior correlated negatively with first dimension (free/friendly versus sad/bored) in the children's group; second dimension (agitated/confident versus angry/bored) amongst the adults; and first dimension (active/excited versus agitated/bored) amongst the experts. More studies are needed to investigate other potential differences in assessing elephants' emotional states by visitors of different ages and backgrounds.

20.
Front Vet Sci ; 8: 599387, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33732737

RESUMEN

The African elephant (Loxodonta africana) is listed as vulnerable, with wild populations threatened by habitat loss and poaching. Clinical pathology is used to detect and monitor disease and injury, however existing reference interval (RI) studies for this species have been performed with outdated analytical methods, small sample sizes or using only managed animals. The aim of this study was to generate hematology and clinical chemistry RIs, using samples from the free-ranging elephant population in the Kruger National Park, South Africa. Hematology RIs were derived from EDTA whole blood samples automatically analyzed (n = 23); manual PCV measured from 48 samples; and differential cell count results (n = 51) were included. Clinical chemistry RIs were generated from the results of automated analyzers on stored serum samples (n = 50). Reference intervals were generated according to American Society for Veterinary Clinical Pathology guidelines with a strict exclusion of outliers. Hematology RIs were: PCV 34-49%, RBC 2.80-3.96 × 1012/L, HGB 116-163 g/L, MCV 112-134 fL, MCH 35.5-45.2 pg, MCHC 314-364 g/L, PLT 182-386 × 109/L, WBC 7.5-15.2 × 109/L, segmented heterophils 1.5-4.0 × 109/L, band heterophils 0.0-0.2 × 109/L, total monocytes 3.6-7.6 × 109/L (means for "regular" were 35.2%, bilobed 8.6%, round 3.9% of total leukocytes), lymphocytes 1.1-5.5 × 109/L, eosinophils 0.0-0.9 × 109/L, basophils 0.0-0.1 × 109/L. Clinical chemistry RIs were: albumin 41-55 g/L, ALP 30-122 U/L, AST 9-34 U/L, calcium 2.56-3.02 mmol/L, CK 85-322 U/L, GGT 7-16 U/L, globulin 30-59 g/L, magnesium 1.15-1.70 mmol/L, phosphorus 1.28-2.31 mmol/L, total protein 77-109 g/L, urea 1.2-4.6 mmol/L. Reference intervals were narrower than those reported in other studies. These RI will be helpful in the future management of injured or diseased elephants in national parks and zoological settings.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA