Method development to characterise elephant tail hairs by LA-ICP-MS to reflect changes in elemental chemistry.

This paper evaluated analytical methods used to generate time-series data from elephant tail hairs, which can be used to reflect changing exposure to environmental geochemistry. Elephant tail hairs were analysed by three methods sequentially, each providing data to inform subsequent analysis. Scanning Electron Microscopy (SEM) and X-ray Microanalysis visually showed the structure of the hair, specific structures such as tubules, and the mineral crusting around the edge of the hair, informing targeting of subsequent analysis by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). LA-ICP-MS generated time-series data which informed sectioning of the tail hairs for subsequent quantitative analysis for potentially toxic elements and micronutrients using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) of dissolved tail hairs. This novel approach to characterise the tail hair enabled time-series analysis to reflect changes in environmental exposure which may result from seasonal or geochemical spatial variation and could inform elephant movement patterns. The seasonal change between wet and dry seasons was reflected down the length of the hair. Correlations were seen between LA-ICP-MS data and ICP-MS data in several elements including Mg, P, Ca, Fe, Na, Mn and U. This study provided time-series data for the analysis of elephant tail hairs by evaluating analytical challenges to obtaining quantitative data, such as improving protocols to ensure removal of extraneous material, determining where to section the tail hairs to best reflect environmental changes/exposure and ensuring representative analyses. A protocol was established to determine mineral status across a 12-18 month time period utilizing single elephant tail hairs.

Cryo-scanning electron microscopy demonstrates that ice morphology is not associated with the post-thaw survival of domestic boar (Sus domesticus) spermatozoa: A comparison of directional and conventional freezing methods.

Directional freezing (in 2 or 10 ml hollow glass tubes) has been reported to improve post-thaw sperm survival parameters compared to conventional methods (in 0.5 ml straws). However, the biophysical properties that increase post-thaw survival are poorly understood. Therefore, the aim for the current study was to investigate the effect of ice morphology on the post-thaw survival of domestic boar spermatozoa directionally and conventionally cryopreserved in 0.5 ml straws. Ice morphology was quantitatively analyzed using a combination of cryo-scanning electron microscopy and Fiji Shape Descriptors. Multivariate analysis found a significant, non-linear effect (p < 0.05) of interface velocity on ice morphology, with an increase in both ice-lake size, as indicated by area and in aspect ratio, at an interface velocity of 0.2 mm/s. By contrast, post-thaw sperm survival (defined as spermatozoa with both intact plasma membranes and acrosomes) was biphasic, with peaks of survival at interface velocities of 0.2 mm/s (54.2 ± 1.9%), and 1.0 or 1.5 mm/s (56.5 ± 1.5%, 56.7 ± 1.7% respectively), and lowest survival at 0.5 (52.1 ± 1.6%) and 3.0 mm/s (51.4 ± 1.9%). Despite numerical differences in Shape Descriptors, there was no difference (p > 0.05) in the post-thaw survival between conventionally and directionally cryopreserved samples at optimal interface velocities of 1.0 or 1.5 mm/s. These findings suggest that: 1) ice morphology has little impact on post-thaw survival of boar spermatozoa, and 2) directional freezing in 0.5 ml straws (rather than 2 or 10 ml hollow glass tubes) may attenuate benefits of directional freezing.

Outcomes of Conservatively Managed Coracoid Fractures in Wild Birds in the United Kingdom.

Coracoid fractures are a frequent presentation in wild birds, commonly caused by collisions with motor vehicles, windows, or other obstacles such as pylons. Despite this, there are few reports of outcomes, and those published consist of small numbers of birds with conflicting results when comparing conservative management with surgical intervention. To determine outcome success of conservative management in a larger population of wild birds, records of 232 adult wild birds in the United Kingdom (UK) with closed unilateral coracoid fractures confirmed on radiography and surviving more than 48 hours after admission were retrospectively analyzed. Conservative management had a high success rate, with 75% (n = 174/232; 95% confidence limits [CL]: 69%, 80%) of all birds successfully released back to the wild. The proportion of raptors successfully returned to the wild was even higher at 97% (n = 34/35; 95% CL: 85%, 99%). A significant difference of 26% (95% CL: 18%, 34%, Fisher exact test, P < .001) was demonstrated when comparing the outcome success of raptors (97%, n = 34/35) to nonraptors (71%, n = 140/198). The median time in captive care until released back to the wild was 30 days (95% CL: 27, 33). Conservative management of coracoid fractures in wild birds in the UK, and in particular in raptors, appears to result in good outcomes. The approach is low cost and noninvasive, in contrast to surgery, and is recommended as the first-line approach of choice in these cases.

The impact of competition on elephant musth strategies: A game-theoretic model.

Mature male African Savannah elephants are known to periodically enter a temporary state of heightened aggression called "musth", often linked with increased androgens, particularly testosterone. Sexually mature males are capable of entering musth at any time of year, and will often travel long distances to find estrous females. When two musth bulls or two non-musth bulls encounter one another, the agonistic interaction is usually won by the larger male. However, when a smaller musth bull encounters a larger non-musth bull, the smaller musth male can win. The relative mating success of musth males is due partly to this fighting advantage, and partly to estrous females' general preference for musth males. Though musth behavior has long been observed and documented, the evolutionary advantages of musth remain poorly understood. Here we develop a game-theoretic model of male musth behavior which assumes musth duration as a parameter, and distributions of small, medium and large musth males are predicted in both time and space. The predicted results are similar to the musth timing behavior observed in the Amboseli National Park elephant population, and further results are generated with relevance to Samburu National Park. We discuss small male musth behavior, the effects of estrous female spatial heterogeneity on musth timing, conservation applications, and the assumptions underpinning the model.

Global population divergence and admixture of the brown rat (Rattus norvegicus).

Native to China and Mongolia, the brown rat (Rattus norvegicus) now enjoys a worldwide distribution. While black rats and the house mouse tracked the regional development of human agricultural settlements, brown rats did not appear in Europe until the 1500s, suggesting their range expansion was a response to relatively recent increases in global trade. We inferred the global phylogeography of brown rats using 32 k SNPs, and detected 13 evolutionary clusters within five expansion routes. One cluster arose following a southward expansion into Southeast Asia. Three additional clusters arose from two independent eastward expansions: one expansion from Russia to the Aleutian Archipelago, and a second to western North America. Westward expansion resulted in the colonization of Europe from which subsequent rapid colonization of Africa, the Americas and Australasia occurred, and multiple evolutionary clusters were detected. An astonishing degree of fine-grained clustering between and within sampling sites underscored the extent to which urban heterogeneity shaped genetic structure of commensal rodents. Surprisingly, few individuals were recent migrants, suggesting that recruitment into established populations is limited. Understanding the global population structure of R. norvegicus offers novel perspectives on the forces driving the spread of zoonotic disease, and aids in development of rat eradication programmes.

Development of a DNA-based microarray for the detection of zoonotic pathogens in rodent species.

The demand for diagnostic tools that allow simultaneous screening of samples for multiple pathogens is increasing because they overcome the limitations of other methods, which can only screen for a single or a few pathogens at a time. Microarrays offer the advantages of being capable to test a large number of samples simultaneously, screening for multiple pathogen types per sample and having comparable sensitivity to existing methods such as PCR. Array design is often considered the most important process in any microarray experiment and can be the deciding factor in the success of a study. There are currently no microarrays for simultaneous detection of rodent-borne pathogens. The aim of this report is to explicate the design, development and evaluation of a microarray platform for use as a screening tool that combines ease of use and rapid identification of a number of rodent-borne pathogens of zoonotic importance. Nucleic acid was amplified by multiplex biotinylation PCR prior to hybridisation onto microarrays. The array sensitivity was comparable to standard PCR, though less sensitive than real-time PCR. The array presented here is a prototype microarray identification system for zoonotic pathogens that can infect rodent species.

An investigation into resting behavior in Asian elephants in UK zoos.

Maintaining adequate welfare in captive elephants is challenging. Few studies have investigated overnight rest behavior in zoo elephants, yet time spent resting has been identified as a welfare indicator in some species. We investigated resting behavior in Asian elephants (Elephas maximus) in UK zoos, with the aim of identifying patterns or preferences in lying rest. Details of standing (SR) and lying (LR) rest behavior were identified by observing video footage of inside enclosures collected for 14 elephants (2 male, 12 female) housed at three UK zoos (Zoo A: 18 nights; Zoo B: 27 nights; Zoo C: 46 nights) from 16:00 to 08:30 (approximately). Elephants engaged in a mean of 58-337 min rest per night. Time of night affected mean duration of LR bouts (P < 0.001); longest bouts were observed between 22:01 and 06:00. Elephants showed a substrate preference when lying to rest; LR was not observed on concrete or tiled flooring. Where sand was available (to 11/14 elephants), all elephants engaged in LR on sand flooring. Only two elephants engaged in LR on rubber flooring (available to 7/14 elephants). Mean duration of rest bouts was greater when a conspecific was within two body lengths than when conspecifics were not (P < 0.01). Our study indicated that elephants show substrate preferences when choosing an area for rest and engage in more rest when conspecifics are in close proximity. The results of this study could be used as a basis for future studies investigating the link between rest and welfare in captive elephants.

Dolphin-WET-Development of a Welfare Evaluation Tool for Bottlenose Dolphins (Tursiops truncatus) under Human Care.

Ensuring high standards of animal welfare is not only an ethical duty for zoos and aquariums, but it is also essential to achieve their conservation, education, and research goals. While for some species, animal welfare assessment frameworks are already in place, little has been done for marine animals under human care. Responding to this demand, the welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe. Their objective was to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus), named Dolphin-WET. The tool encompasses 49 indicators that were either validated through peer review or management-based expertise. The first of its kind, the Dolphin-WET is a species-specific welfare assessment tool that provides a holistic approach to evaluating dolphin welfare. Inspired by Mellor's Five Domains Model and the Welfare Quality®, its hierarchical structure allows for detailed assessments from overall welfare down to specific indicators. Through combining 37 animal-based and 12 resource-based indicators that are evaluated based on a two- or three-level scoring, the protocol offers a detailed evaluation of individual dolphins. This approach allows for regular internal monitoring and targeted welfare management, enabling caretakers to address specific welfare concerns effectively.

Relationships between soil and badger elemental concentrations across a heterogeneously contaminated landscape.

Understanding the links between environmental and wildlife elemental concentrations is key to help assess ecosystem functions and the potential effects of legacy pollutants. In this study, livers from 448 European badgers (Meles meles) collected across the English Midlands were used to investigate the relationship between elemental concentrations in topsoils and wildlife. Mean soil sample concentrations within 2 km of each badger, determined using data from the British Geological Survey's 'Geochemical Baseline Survey of the Environment', were compared to badger liver elemental concentrations, focusing primarily on Ag, As, Cd, Cr, Cu, K, Mn, Pb, Se, Zn. Generally, the badgers appeared to have elemental concentrations comparable with those published for other related animals, though Cu concentrations tended to be lower than expected. While there was no relationship between soil and badger liver concentrations for most biologically essential elements, biologically non-essential elements, specifically Pb, Cd, As, and Ag, were positively correlated between soil and badger livers. Lead and Cd, the elements with the strongest relationships between soils and badger livers, were primarily elevated in badgers collected in Derbyshire, a county with a millennia-long history of Pb mining and significant Pb and Cd soil pollution. Cadmium concentrations in badgers were also, on average, almost nine times higher than the local soil concentrations, likely due to Cd biomagnification in earthworms, a dietary staple of badgers. While badgers are good models for studying associations between soil and wildlife elemental concentrations, due to their diet, burrowing behaviours, and site fidelity, all flora and fauna local to human-modified environments could be exposed to and impacted by legacy pollutants.

Incorporating biodiversity responses to land use change scenarios for preventing emerging zoonotic diseases in areas of unknown host-pathogen interactions.

The need to reconcile food production, the safeguarding of nature, and the protection of public health is imperative in a world of continuing global change, particularly in the context of risks of emerging zoonotic disease (EZD). In this paper, we explored potential land use strategies to reduce EZD risks using a landscape approach. We focused on strategies for cases where the dynamics of pathogen transmission among species were poorly known and the ideas of "land-use induced spillover" and "landscape immunity" could be used very broadly. We first modeled three different land-use change scenarios in a region of transition between the Cerrado and the Atlantic Forest biodiversity hotspots. The land-use strategies used to build our scenarios reflected different proportions of native vegetation cover, as a proxy of habitat availability. We then evaluated the effects of the proportion of native vegetation cover on the occupancy probability of a group of mammal species and analyzed how the different land-use scenarios might affect the distribution of species in the landscape and thus the risk of EZD. We demonstrate that these approaches can help identify potential future EZD risks, and can thus be used as decision-making tools by stakeholders, with direct implications for improving both environmental and socio-economic outcomes.

Behaviour and Welfare Impacts of Releasing Elephants from Overnight Tethers: A Zimbabwean Case Study.

Within the southern African elephant tourism industry, chaining or tethering elephants is still a relatively routine practice, despite the known negative impacts. Cited reasons for chaining include fear of aggressive interactions between elephants when handlers are absent, or a general increase in expression of aggressive behaviours (both to other elephants and to their human handlers). In Zimbabwe, concerns expressed include the danger of elephants escaping and entering human-inhabited areas. Four male semi-captive elephants at a Zimbabwe tourist facility were taken off overnight (~12 h) tethers and were placed in small pens ('bomas'), approximate sizes from 110 m2 to 310 m2), as part of a strategy to improve elephant welfare. Behavioural data were collected from overnight videos from December 2019 to March 2020, between 18:00 to 06:00, using focal, instantaneous sampling (5-min interval). Data were collected for three nights at three time periods: (i) Tethered; (ii) approximately four weeks post-release; (iii) approximately eight weeks post-release. Behavioural change over these time points was analysed using general linear models with quasibinomial error structures. Behavioural changes indicative of improved welfare were observed following these management changes, and no significant increases in aggression were observed either between elephants, or towards their human handlers. Proportion of time engaging in lying rest was higher in the first month after release from tethering (mean ± SD, 50 ± 14%) than when elephants were tethered (20 ± 18%) (p < 0.05). Additionally, although not statistically significant, stereotypies were reduced when elephants were no longer tethered (4 ± 6% observations tethered compared to 2 ± 2% off tethers), and positive social behaviour also increased (1 ± 1% on tethers, 2 ± 2% off tethers), with the greatest improvements seen in the pair-housed elephants. To improve elephant welfare in southern African tourism facilities we strongly advocate that less restrictive management practices which enable greater choice and freedom of movement overnight are implemented.

Human health implications from consuming eggs produced near a derelict metalliferous mine: a case study.

Lead pollution from metalliferous mines can have major environmental and health effects long after the mines have closed. Animals living near derelict mine sites can inadvertently ingest lead-contaminated soils, causing them to accumulate lead and potentially experience significant adverse health effects. Human food products, such as eggs, produced near metalliferous mines may also be contaminated with lead. The focus of this case study was to determine whether free-range chickens living near a derelict lead mine had high lead body burdens, whether they were producing eggs with elevated lead concentrations, and whether these eggs could be hazardous to human health. Soil samples and chicken egg, feather, blood, and bone samples were collected from a small farm near an abandoned metalliferous mine. The soil in and around the chicken pens contained lead concentrations that were elevated above established soil lead baseline concentrations. The lead concentrations in the chicken feather, blood, and bone samples were consistent with lead toxicity and indicated long-term, continuous exposure. Finally, the lead concentrations in the eggs were significantly greater than those found in commercial eggs. Based on previously established lead benchmark dose levels, humans, and in particular, children, could experience adverse health impacts if they routinely consumed these eggs. Environmental lead contamination continues to pose a major health risk for humans, and further research, understanding, and awareness are required to safeguard the public from the risks of consuming food produced near derelict mines.

How can mating systems inform future biobanking strategies? An illustration using two Indonesian bovids, banteng (Bos javanicus) and lowland anoa (Bubalus depressicornis).

Storing cryopreserved spermatozoa in a genome resource bank safeguards against the loss of heterozygosity in endangered species and provides opportunities to reincorporate genes into populations through the application of assisted reproductive technologies. The aim of this study was to demonstrate the effect of breeding strategy on ejaculate characteristics to illustrate how this information may be used to select appropriate methods for the storage and use of cryopreserved sperm. In the present study, ejaculates from a polygynous bovid, banteng (Bos javanicus), were characterized (motility 72.7 ± 4.3%; total sperm count 2,702 ± 764 ×106 sperm; morphologically normal sperm 87.9 ± 3.0%), as well as ejaculates from a monogamous bovid, lowland anoa (Bubalus depressicornis; motility 47.5 ± 5.4%; total sperm count 279 ± 84 ×106 sperm; morphologically normal sperm 69.0 ± 6.1%). As banteng produce an ejaculate with characteristics similar to domestic cattle, translating assisted reproductive technologies from domestic cattle is feasible. By contrast, lowland anoa produce smaller quantities of sperm with a higher prevalence of morphologically abnormal sperm; thus, alternative protocols, optimized for the storage and use of ejaculates containing lower quantities of sperm, is necessary. Sperm tail length was more conserved in banteng (CV 2.7%) than lowland anoa (CV 6.4%) and could be due to differences in levels of sperm competition between species. Additionally, the use of three different diluents (Biladyl, TES-Tris yolk buffer, and whole milk) were investigated for banteng sperm cryopreservation. Sperm cryopreserved in Biladyl and whole milk diluents produced significantly higher post-thaw survival parameters then TES-Tris yolk buffer.

Confidence as a barrier to the use of problem-based learning in veterinary undergraduate students.

Problem-based or case-based learning is a popular method of instruction in clinical degrees such as veterinary science, nursing, and medicine. It is difficult, however, for students to adapt to this learning method, and this difficulty has been well described. The present study surveyed first-year undergraduate veterinary students at the University of Nottingham about the challenges they faced upon beginning problem-based learning sessions. A surprisingly large percentage of students (36% of females and 38% of males) reported a lack of confidence in speaking in front of the other students as a concern they experienced during their first term. Conversely, only 10% of the female students (and none of the male students) reported overconfidence as a problem. This is in contrast to the perceptions of the staff members who facilitated the sessions who reported that 14% of the students exhibited underconfidence and 14% exhibited overconfidence. The difference between the female and male students' responses as well as the difference between the perceptions of students and those of facilitators is statistically significant (G-test p<.05).

A safer method for studying hormone metabolism in an Asian elephant (Elephas maximus): accelerator mass spectrometry.

Noninvasive hormone assays provide a way to determine an animal's health or reproductive status without the need for physical or chemical restraint, both of which create unnecessary stress for the animal, and can potentially alter the hormones being measured. Because hormone metabolism is highly species-specific, each assay must be validated for use in the species of interest. Validation of noninvasive steroid hormone assays has traditionally required the administration of relatively high doses of radiolabelled compounds (100 µCi or more of (14)C labeled hormone) to permit subsequent detection of the excreted metabolites in the urine and feces. Accelerator mass spectrometry (AMS) is sensitive to extremely low levels of rare isotopes such as (14)C, and provides a way to validate hormone assays using much lower levels of radioactivity than those traditionally employed. A captive Asian bull elephant was given 1 µCi of (14)C-testosterone intravenously, and an opportunistic urine sample was collected 2 hr after the injection. The sample was separated by HPLC and the (14)C in the fractions was detected by AMS to characterize the metabolites present in the urine. A previously established HPLC protocol was used, which permitted the identification of fractions into which testosterone sulfate, testosterone glucuronide, and the parent compound testosterone elute. Results from this study indicate that the majority of testosterone excreted in the urine of the Asian bull elephant is in the form of testosterone sulfate. A small amount of testosterone glucuronide is also excreted, but there is no parent compound present in the urine at all. These results underscore the need for enzymatic hydrolysis to prepare urine samples for hormone assay measurement. Furthermore, they highlight the importance of proper hormone assay validation in order to ensure accurate measurement of the desired hormone. Although this study demonstrated the utility of AMS for safer validation of noninvasive hormone assays in nondomestic species, this methodology could also be applied to studies of nutrient metabolism and drug pharmakokinetics, both areas in great need of further study in wildlife species.

Potential bio-indicators for assessment of mineral status in elephants.

The aim of this study was two-fold: (1) identify suitable bio-indicators to assess elemental status in elephants using captive elephant samples, and (2) understand how geochemistry influences mineral intake. Tail hair, toenail, faeces, plasma and urine were collected quarterly from 21 elephants at five UK zoos. All elephant food, soil from enclosure(s), and drinking water were also sampled. Elemental analysis was conducted on all samples, using inductively coupled plasma mass spectrometry, focusing on biologically functional minerals (Ca, Cu, Fe, K, Mg, Mn, Na, P, Se and Zn) and trace metals (As, Cd, Pb, U and V). Linear mixed modelling was used to identify how keeper-fed diet, water and soil were reflected in sample bio-indicators. No sample matrix reflected the status of all assessed elements. Toenail was the best bio-indicator of intake for the most elements reviewed in this study, with keeper-fed diet being the strongest predictor. Calcium status was reflected in faeces, (p 0.019, R2 between elephant within zoo - 0.608). In this study urine was of no value in determining mineral status here and plasma was of limited value. Results aimed to define the most suitable bio-indicators to assess captive animal health and encourage onward application to wildlife management.

Spatial geochemistry influences the home range of elephants.

The unique geochemistry surrounding the Palabora Mining Company (PMC) land may act as a micronutrient hotspot, attracting elephants to the area. The PMC produces refined copper and extracts phosphates and other minerals. Understanding the spatial influence of geochemistry on the home range size of African elephants is important for elephant population management and conservation. The home ranges of collared elephants surrounding the PMC were significantly smaller (P = 0.001) than conspecifics in surrounding reserves, suggesting that their resource needs were met within these smaller areas. Environmental samples (soil, water and plants) were analysed from the mine area and along six transects radiating from the mine centre. Tail hair and faecal samples from elephants at the PMC, and conspecifics within the surrounding area were analysed. All samples were analysed for minerals essential to health and potentially toxic elements (PTEs; As, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, Pb, Se, U, V and Zn). Results show that the geochemistry at the PMC is different compared to surrounding areas, with significant elevations seen in all analysed minerals and PTEs in soil closer to the mine, thereby drawing the elephants to the area. Additionally significant elevations were seen in elements analysed in water and vegetation samples. Elephant tail hair from elephants at the mine was significantly greater in Cd, whilst Mg, P, Cu, As, Cd, Pb and U concentrations were significantly greater in elephant faecal samples at the mine compared to the non-mine samples. When micronutrient hotspots overlap with human activity (such as mining), this can lead to poor human-elephant coexistence and thus conflict. When managing elephant populations, the influence of mineral provision on elephant movement must be considered. Such detailed resource information can inform conservation efforts for coordinated programmes (UN SDGs 15 and 17) and underpin sustainable economic activity (UN SDG 8, 11 and 12).

Development of a behavioural welfare assessment tool for routine use with captive elephants.

There has been much concern in recent years about the welfare of elephants in zoos across North America and Europe. While some previous studies have assessed captive elephant welfare at a particular point in time, there has been little work to develop methods which could be used for regular, routine welfare assessment. Such assessment is important in order to track changes in welfare over time. A welfare assessment tool should be rapid, reliable, and simple to complete, without requiring specialist training and facilities; welfare assessments based on behavioural observations are well suited to this purpose. This report describes the development of a new elephant behavioural welfare assessment tool designed for routine use by elephant keepers. Tool development involved: (i) identification of behavioural indicators of welfare from the literature and from focus groups with relevant stakeholders; (ii) development of a prototype tool; (iii) testing of the tool at five UK zoological institutions, involving 29 elephants (representing 46% of the total UK captive elephant population of 63 animals); (iv) assessment of feasibility and reliability of aspects of the prototype tool; (v) assessment of the validity of each element of the tool to reflect the relevant behaviour by comparing detailed behavioural observations with data from the prototype tool; (vi) assessment of known-groups criterion validity by comparing prototype tool scores in individuals with demographics associated with better or worse welfare; (vii) development of a finalised tool which incorporated all elements of the tool which met the criteria set for validity and reliability. Elements of the tool requiring further consideration are discussed, as are considerations for appropriate application and interpretation of scores. This novel behavioural welfare assessment tool can be used by elephant-holding facilities for routine behavioural welfare monitoring, which can inform adjustments to individual welfare plans for each elephant in their collection, to help facilities further assess and improve captive elephant welfare. This study provides an example of how an evidence-based behavioural welfare assessment tool for use by animal caretakers can be developed within the constraints of zoo-based research, which could be applied to a range of captive species.

African savanna elephants (Loxodonta africana) as an example of a herbivore making movement choices based on nutritional needs.

BACKGROUND: The increasing human population and global intensification of agriculture have had a major impact on the world's natural ecosystems and caused devastating effects on populations of mega-herbivores such as the African savanna elephants, through habitat reduction and fragmentation and increased human-animal conflict. Animals with vast home ranges are forced into increasingly smaller geographical areas, often restricted by fencing or encroaching anthropogenic activities, resulting in huge pressures on these areas to meet the animals' resource needs. This can present a nutritional challenge and cause animals to adapt their movement patterns to meet their dietary needs for specific minerals, potentially causing human-animal conflict. The aim of this review is to consolidate understanding of nutritional drivers for animal movement, especially that of African savanna elephants and focus the direction of future research. Peer reviewed literature available was generally geographically specific and studies conducted on isolated populations of individual species. African savanna elephants have the capacity to extensively alter the landscape and have been more greatly studied than other herbivores, making them a good example species to use for this review. Alongside this, their movement choices, potentially linked with nutritional drivers could be applicable to a range of other species. Relevant case study examples of other herbivores moving based on nutritional needs are discussed. METHODS: Three databases were searched in this review: Scopus, Web of Science and Google Scholar, using identified search terms. Inclusion and exclusion criteria were determined and applied as required. Additional grey literature was reviewed as appropriate. RESULTS: Initial searches yielded 1,870 records prior to application of inclusion and exclusion criteria. A less detailed review of grey literature, and additional peer-reviewed literature which did not meet the inclusion criteria but was deemed relevant by the authors was also conducted to ensure thorough coverage of the subject. DISCUSSION: A review of peer reviewed literature was undertaken to examine nutritional drivers for African elephant movement, exploring documented examples from free-ranging African savanna elephants and, where relevant, other herbivore species. This could help inform prediction or mitigation of human-elephant conflict, potentially when animals move according to nutritional needs, and related drivers for this movement. In addition, appropriate grey literature was included to capture current research.