Digestive physiology of captive giant anteaters (Myrmecophaga tridactyla ): determinants of faecal dry matter content

Diet composition and apparent digestibility in giant anteaters (Myrmecophaga tridactyla) kept under human care

Giant anteaters have limited biological knowledge and pose challenges in captivity, primarily due to their highly specialized feeding habits. This study aimed to evaluate the diet and its apparent digestibility in captive giant anteaters, seeking to understand the relationship between the offered diet and its utilization by animals under human care at institutions and zoos in the state of São Paulo. Seventeen adult giant anteaters (Myrmecophaga tridactyla), comprising 10 females and 7 males, were used to determine the nutritional composition of their diet, collect feces for bromatological analysis, and assess diet digestibility. The chemical composition of the offered foods and feces was evaluated, and the apparent digestibility of the diet was calculated. Analysis of the diets revealed that their nutritional composition did not differ significantly among institutions, despite variations in ingredient composition. The protein and lipid contents of the diets were as follows: 25.6% and 6.4% (diet 1), 34.7% and 10.9% (diet 2), 31.9% and 10.3% (diet 3), and 38.2% and 12.7% (diet 4), respectively. Ether extract (EE) had the highest apparent digestibility coefficient (ADC) (general mean 91 ± 4.8). The mean ADC was 68.9, 67.6, 79.6, and 89.9 for crude protein (CP); 89.8, 88.8, 92.5, and 94.2 for EE; 44.8, 64, 71.1, and 95.3 for nitrogen-free extract; and 80.5, 43.5, 43, and 87.1 for crude fiber, for diets 1, 2, 3, and 4, respectively. It is concluded that diets at São Paulo institutions showed good digestibility, especially for crude protein and ether extract. However, most animals had soft feces, indicating room for improvement. Energy intake affected body condition, emphasizing the need for tailored diets. Ether extract should not exceed 10%, and diets should provide 75-100% of maintenance energy, with regular monitoring of body condition scores.

Nutrient Digestibility in Zoo-Kept Tapirs (Tapirus spp) as Compared to Other Herbivores

Tapirs are hindgut fermenters with a natural diet dominated by browse, with a certain proportion of wild fruit. By contrast, diets fed to tapirs in zoos are often dominated by domestic fruit and other sources of easily digestible carbohydrates, which have been linked to obesity and various health problems. We aimed at better understanding the digestive physiology of tapirs, measuring the digestive efficiency of 13 lowland (Tapirus terrestris) and five Malayan (Tapirus indicus) tapirs from five zoos on various zoo diets by recording intake and total faecal excretion. Additionally, we aimed at evaluating zoo diets, by assessing relationships between dietary characteristics and data on intake and faeces consistency, and compared the data gained in the zoo study to those of faecal samples of free-ranging tapirs. Tapirs showed digestive principles reported in other herbivores, such as higher levels of metabolic faecal nitrogen and a lower intake on diets of higher digestibility, or a decrease in digestibility with increasing dietary fibre concentrations. Compared to horses or grazing rhinoceroses, organic matter digestibility in tapirs was more negatively affected by dietary fibre; additionally, tapirs had comparatively low fibre digestibility. This is possibly linked to their comparatively poor chewing efficacy. The readiness to ingest a hay-only diet was directly proportional to the amount of hay in the usual zoo diet, supporting reports that it may be difficult to achieve high hay intakes in tapirs instantaneously. Faeces consistency was closer to the natural condition with higher proportions of roughage in the diet. Compared to a set of faecal samples from the wild, zoo faeces were generally lower in fibre. This study supports previous suggestions that zoo tapirs could benefit, in terms of mimicking their digestive physiology and feeding behaviour in natural habitats, from diets based on a readily ingested roughage source, especially from browse.

The natural diet composition of young piglets suggests an overlook of fibre and food structure in farmed suckling piglets

BACKGROUND

The often disappointing intake of creep feed by suckling piglets coincides with a limited ability to cope with challenges such as weaning diarrhoea. Investigating the dietary nutrient profile of piglets (Sus scrofa) in the wild may help to improve nutrition for farmed piglets. This study was conducted to analyse the stomach content of feral piglets and their farmed counterparts, and to compare them with the composition of commercial creep feeds. Forty feral piglets (4.6 ± 1.4 kg) living in a wild herd were tracked and legally hunted in the Bahía Samborombón (Buenos Aires, Argentina). Their gastric contents were collected for analysing macronutrients. Twenty-eight farmed suckling piglets of similar ages were sourced from a Dutch research farm, and their stomach contents were collected and pooled into fourteen samples with the same procedure for comparison. Additionally, the composition data of twenty-five commercial feeds was also collected.

RESULTS

A higher dry matter content was observed in the farmed piglets' stomachs (233 vs. 148 g/kg, P < 0.05). The gastric crude protein concentration was similar between both groups but the crude fat concentration was higher in the stomach of farmed animals (525 vs. 238 g/kg DM, P < 0.05), while feral piglets consumed more ash and fibre (P < 0.05). A similar concentration of non-fibrous carbohydrates (NFC) on metabolizable energy basis was observed by calculation through the NRC's guideline (P > 0.05). Within the fibre content, significantly greater concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were observed in the stomach of feral piglets than in those of farmed piglets (282 vs. 36 g/kg, 158 vs. 9 g/kg DM, 53 vs. 3 g/kg DM, respectively, P < 0.05). Similar protein concentrations were observed between the gastric content of feral piglets and creep feed, while significantly higher crude ash and crude fat concentrations were found in feral piglets' consumption (P < 0.05).

CONCLUSION

In conclusion, piglets in natural conditions consume much more fibre-from coarse plant material-compared to farmed piglets receiving creep feed. Although technical performance is distinctly different between nature and farm, it raises the question whether suckling piglets under farming conditions would benefit from a more fibrous and coarser creep feed.

Evaluation and Ultrasonographic Validation of the Body Condition Score in Giant Anteaters (Myrmecophaga tridactyla Linnaeus, 1758)

The giant anteater (Myrmecophaga tridactyla) is a unique species in risk of extinction nationally and internationally due to ongoing environmental and anthropogenic pressures, therefore requiring continuous conservation efforts. Under human care, obesity and nutrition-related diseases are major concerns. Body condition scoring (BCS) is an important tool for assessing animal fitness in natural and ex situ environments. This study aims to evaluate the applicability and reliability of BCS and morphometric measures, associated with ultrasound measurements of subcutaneous fat thickness (SFT), as tools to estimate the body condition of giant anteaters. Twenty free-ranging and twenty-two zoo-kept giant anteaters were assessed. The animals were weighed and classified by BCS, followed by biometric measurements and calculations of two body condition indices-the ratio index (RI) and the condition index 2 (ICC2). Subcutaneous fat measurements were taken by ultrasound in the lumbar, hip and flank of the captive anteaters. Captive animals exhibited higher body mass, BCS, measures of forearm, thorax, abdomen, neck, femur, tibia, humerus, RI and ICC2 compared to their free-ranging counterparts. Body mass correlated positively with all parameters except SFT. BCS showed moderate to strong correlations with body mass, RI, ICC2, thoracic, and abdominal circumferences. SFT correlated with BCS. Free-ranging anteaters consistently showed moderate BCS, while captive ones ranged from lean to obese, with relevant subcutaneous fat accumulation in the flank and hip. The resulting BCS protocol for the species was considered adequate to evaluate nutritional status under both free-range and managed-care conditions.

Larger Than Life? Body Mass Records of Zoo-Managed Giant Anteaters (Myrmecophaga tridactyla)

It has been suggested repeatedly that zoo-kept giant anteaters (Myrmecophaga tridactyla) have higher body masses than their free-ranging conspecifics. Here, we assess this hypothesis by comparing body mass data of 184 female and 173 male individuals kept in zoos to published and unpublished data of free-ranging animals (n = 215). In zoos, the average adult body mass of all individuals was 45.9 ± 9.6 kg (range 19.2-72.6 kg), whereas body mass for free-ranging specimens was 33.0 ± 2.3 kg (21-45.5 kg). Among those zoo animals in which a sufficient number of subsequent intra-annual measures had been taken, we assessed visually whether regular, annual fluctuations in body mass were evident. We observed regular, likely seasonal, cycles in body mass, which (i) may be plausibly attributed to ambient temperature changes that affect the body temperature of anteaters, and (ii) would likely not have occurred if the animals were affected by obesity. Additionally, we explain our hypothesis that in the case of giant anteaters, the discrepancy in body mass between natural habitats and zoos most likely is not indicative of a generally obese population in zoos, as is typically concluded in the case of similar comparisons in primates, but represents an unleashing of the full growth potential of the species by conditions of optimal energy and nutrient provision. Future recording of not only body mass but also body dimensions is recommended to better compare the body condition of free-ranging and zoo-managed individuals.

Microbiome composition and presence of cultivable commensal groups of Southern Tamanduas (Tamandua tetradactyla) varies with captive conditions

Southern Tamanduas (Tamandua tetradactyla) belong to the specialized placental myrmecophages. There is not much information about their intestinal microbiome. Moreover, due to their food specialization, it is difficult to create an adequate diet under breeding conditions. Therefore, we used 16S rDNA amplicon sequencing to analyze the fecal microbiome of captive Southern Tamanduas from four locations in the Czech Republic and evaluated the impact of the incoming diet and facility conditions on microbiome composition. Together with the microbiome analysis, we also quantified and identified cultivable commensals. The anteater fecal microbiome was dominated by the phyla Bacillota and Bacteroidota, while Pseudomonadota, Spirochaetota, and Actinobacteriota were less abundant. At the taxonomic family level, Lachnospiraceae, Prevotellaceae, Bacteroidaceae, Oscillospiraceae, Erysipelotrichaceae, Spirochaetaceae, Ruminococcaceae, Leuconostocaceae, and Streptococcaceae were mainly represented in the fecal microbiome of animals from all locations. Interestingly, Lactobacillaceae dominated in the location with a zoo-made diet. These animals also had significantly lower diversity of gut microbiome in comparison with animals from other locations fed mainly with a complete commercial diet. Moreover, captive conditions of analyzed anteater included other factors such as the enrichment of the diet with insect-based products, probiotic interventions, the presence of other animals in the exposure, which can potentially affect the composition of the microbiome and cultivable microbes. In total, 63 bacterial species from beneficial commensal to opportunistic pathogen were isolated and identified using MALDI-TOF MS in the set of more than one thousand selected isolates. Half of the detected species were present in the fecal microbiota of most animals, the rest varied across animals and locations.

Survey of the feeding management of giant anteaters (Myrmecophaga tridactyla) and tamanduas (Tamandua tetradactyla) in the EAZA ex-situ programme

Feeding giant anteaters and tamanduas as insectivorous species provides a lot of challenges for zoological institutions. In the last decades an in-house mixture, called 'Dortmund mixture', was the most common feed used in giant anteaters and tamanduas in many countries within the European Association of Zoos and Aquaria ex-situ Programme (EEP). Some nutritional problems occurred due to imbalances in the diets. The more recent nutritional recommendations for both species advise an adapted and balanced complete feed formulated for insectivorous species due to different problems arising with an in-house mixed feed as Dortmund mixture. To objectify the present situation a questionnaire was designed and sent out to 78 institutions of the EEPs for giant anteater(s) and tamandua(s). The questionnaire was divided into different sections and asked for data on husbandry, health status, feeding, especially feed composition, feed supplementation and faecal consistency. It was completed by 45 institutions with data for 130 animals, 89 giant anteaters and 41 tamanduas. The data thus represent 54% and 59% of the EEP populations. For both species, a complete feed is mainly utilised. Especially institutions that have integrated anteaters and tamanduas into their facilities during the last 10 and 20 years, use a complete feed. Regarding the in-house mixtures, there are distinct differences, both in composition and amount of each ingredient used. The evaluation of the feeds used for enrichment, for example, shows a clear species difference. While in tamanduas mainly insects are used for this purpose, in giant anteaters it is mainly fruits and avocado. In contrast to the past, many anteaters today are fed an adapted complete feed. Surprisingly, concerning feeding supplements the use of fat-soluble vitamins and combined vitamin-mineral preparations is still common in both species. More effort needs to be put into enforcing current feeding recommendations, especially for the giant anteaters.

Insectivore Nutrition - A Review of Current Knowledge

Insectivores are represented in virtually all taxa, although more is known about mammalian and avian insectivore nutrition than for reptiles, amphibia and fish. Establishing nutrient requirements is challenging but recommendations should be based on data from similar taxa, similar GI tract physiology, and known nutritional concerns. In order to provide an appropriate diet for insectivores, consideration must be given to anatomy and method for procuring insects in free-ranging habitats, availability of feeder insects and the resulting dietary nutrient profiles, and complementing those profiles with appropriate diet items from various other categories including formulated feed, produce, animal matter, seeds or grains etc. Consideration of known nutritional concerns for a given species, and the variation in energy requirements in a captively managed situation are essential.

Metagenomics uncovers dietary adaptations for chitin digestion in the gut microbiota of convergent myrmecophagous mammals

IMPORTANCE

Myrmecophagous mammals are specialized in the consumption of ants and/or termites. They do not share a direct common ancestor and evolved convergently in five distinct placental orders raising questions about the underlying adaptive mechanisms involved and the relative contribution of natural selection and phylogenetic constraints. Understanding how these species digest their prey can help answer these questions. More specifically, the role of their gut microbial symbionts in the digestion of the insect chitinous exoskeleton has not been investigated in all myrmecophagous orders. We generated 29 new gut metagenomes from nine myrmecophagous species to reconstruct more than 300 bacterial genomes in which we identified chitin-degrading enzymes. Studying the distribution of these chitinolytic bacteria among hosts revealed both shared and specific bacteria between ant-eating species. Overall, our results highlight the potential role of gut symbionts in the convergent dietary adaptation of myrmecophagous mammals and the evolutionary mechanisms shaping their gut microbiota.

Assessment of Feeding Behavior of the Zoo-Housed Lesser Anteater (Tamandua tetradactyla) and Nutritional Values of Natural Prey

Very little information is available to zoo managers on the nutritional preferences of the lesser anteater, a highly specialized predator. By studying lesser anteater feeding behavior, we expect to contribute to improved management decisions and individual welfare experiences. We studied the response of zoo-housed lesser anteaters (n = 7) to feeders with live ants (Acromyrmex lundi) and termites (Cortaritermes fulviceps), and we also evaluated the nutritional values of these prey. We individually evaluated each lesser anteater (3 sessions), recording activities by camera. We ground insect samples into a coarse meal and evaluated in vitro biochemical parameters (humidity, lipids proteins, ash, and carbohydrates). Lesser anteaters spent more time with termites than with ants and consumed more termites. Ant meal presented a higher protein and lipid content than termite meal (35.28 ± 0.18% vs. 18.19 ± 0.34% and 16.95 ± 0.13% vs. 6.54 ± 0.31%, respectively), and carbohydrate digestibility was higher in termites. These findings indicate an association between the level of insect consumption and nutritional and digestibility values. This is the first exploration of lesser anteater responses to the presence of social insects in feeders and may serve to guide the study of food preferences in captivity.

Preliminary evidence for a forestomach washing mechanism in llamas (Lama glama)

Dust and grit are ingested by herbivores in their natural habitats along with the plants that represent their selected diet. Among the functions of the rumen, a washing of ingesta from adhering dust and grit has recently been demonstrated. The putative consequence is a less strenuous wear on ruminant teeth by external abrasives during rumination. The same function should theoretically apply to camelids, but has not been investigated so far. We fed six llamas (Lama glama) a diet of grass hay and a lucerne-based pelleted food in which fine sand had been included at about 8% of ingredients, for ad libitum consumption for 6 weeks. Subsequently, animals were slaughtered and content of the different sections of the gastrointestinal tract was sampled for the analysis of dry matter (DM), total ash, and acid detergent insoluble ash (ADIA, a measure for silica). Additionally, two of the animals were subjected to whole-body computer tomography (CT) after death in the natural sternal resting position. No clinical problems or macroscopic changes in the faeces were observed during the experimental period. The results indicate an accumulation of ADIA in the C3 compartment of the stomach complex, in particular in the posterior portion that is the equivalent of the abomasum in ruminants. By contrast, contents of the C1, from which material is recruited for regurgitation and rumination, were depleted of ADIA, indicating that the contents had largely been washed free of sand. The washing effect is an unavoidable side effect of the flotation- and sedimentation-based sorting mechanisms in the ruminant and the camelid forestomachs. In theory, this should allow ruminants and camelids to live in similar habitats as nonruminant herbivores at lower degrees of hypsodonty.

Biomonitoring mercury contamination using fur from roadkilled giant anteaters

The giant anteater (Myrmecophaga tridactyla) can occur in both preserved and anthropogenic environments in Brazilian biomes. The Cerrado biome, where the samples were collected, is considered one of the world's biodiversity hotspots; however, a large part of it has been converted to pasture and agricultural land. In this environment, animals may be exposed to contaminants, such as mercury (Hg). Despite its immense biodiversity, there are few studies investigating Hg contamination in terrestrial mammals in Brazil. This study aimed to create a baseline for Hg levels in giant anteater fur and establish which biotic and abiotic variables can influence its concentration. Total Hg (THg) concentrations were determined by cold vapor atomic absorption spectrometry in 141 individuals sampled on highways between January and October 2017, in the state of Mato Grosso do Sul, Brazil. THg concentrations in fur ranged from 0.27 to 4.77 μg g ^-1. The decomposition stage of the carcasses and vehicular traffic volume on highways did not influence the THg concentrations. Juveniles presented lower THg concentrations than adults. A spatial pattern of higher concentrations in the eastern-southeastern region of the state was found, which could be related to anthropogenic impacts; however, no clear links have been established. The THg concentrations in giant anteaters' fur seems higher than expected considering the trophic position of the species. Despite this, the range was in accordance with studies of other Brazilian terrestrial mammals and within safe threshold levels. This study indicates the potential of utilizing roadkilled fauna to monitor large-scale contamination in wildlife.

Effect of food limitation and reproductive activity on fecal glucocorticoid metabolite levels in banded mongooses

Background

Glucocorticoids mediate responses to perceived stressors, thereby restoring homeostasis. However, prolonged glucocorticoid elevation may cause homeostatic overload. Using extensive field investigations of banded mongoose (Mungos mungo) groups in northern Botswana, we assessed the influence of reproduction, predation risk, and food limitation on apparent homeostatic overload (n=13 groups, 1542 samples from 268 animals). We experimentally manipulated reproduction and regulated food supply in captive mongooses, and compared their glucocorticoid responses to those obtained from free-living groups.

Results

At the population level, variation in glucocorticoid levels in free-living mongooses was explained by food limitation: fecal organic matter, recent rainfall, and access to concentrated anthropogenic food resources. Soil macrofauna density and reproductive events explained less and predation risk very little variation in glucocorticoid levels. Reproduction and its associated challenges alone (under regulated feeding conditions) increased glucocorticoid levels 19-fold in a captive group. Among free-living groups, glucocorticoid elevation was seasonal (occurring in late dry season or early wet season when natural food resources were less available), but the timing of peak glucocorticoid production was moderated by access to anthropogenic resources (groups with fewer anthropogenic food sources had peaks earlier in dry seasons). Peak months represented 12- and 16-fold increases in glucocorticoids relative to nadir months with some animals exhibiting 100-fold increases. Relative to the captive group nadir, some free-living groups exhibited 60-fold increases in peak glucocorticoid levels with some animals exhibiting up to 800-fold increases. Most of these animals exhibited 1- to 10-fold increases relative to the captive animal peak.

Conclusions

Banded mongooses exhibit seasonal chronic glucocorticoid elevation, associated primarily with food limitation and secondarily with reproduction. Magnitude and duration of this elevation suggests that this may be maladaptive for some animals, with possible fitness consequences. In late dry season, this population may face a convergence of stressors (food limitation, agonistic encounters at concentrated food resources, evictions, estrus, mate competition, parturition, and predation pressure on pups), which may induce homeostatic overload.

Digesta retention time and recovery rates of ants and termites in Chinese pangolins (Manis pentadactyla)

Pangolins are myrmecophagous mammals whose biology and ecology remain poorly studied. Termite mandibles and ant head capsules are the two primary remains found in pangolin feces. Determining the retention time of insect cuticles is important for understanding the digestive physiology of pangolins, while determining the recovery rate of termites and ants in feces is required to estimate the number of these prey items that are consumed by pangolins. In this study, the authors conducted feeding trials with captive Chinese pangolins (Manis pentadactyla). Sixty grams of the fungus-growing termite Odontotermes formosanus (18,816 individuals) and 15-20 g of the yellow crazy ant Anoplolepis gracilipes (14,400-19,200 individuals) were fed to each pangolin. After feeding, pangolin feces were collected daily for 1 week. The authors also assessed the accuracy of using chromium (III) oxide powder (Cr₂ O₃ ) as a proxy for determining gut passage time, as has been done in previous studies. The results showed that remaining termite mandibles and ant head capsules in feces peaked at 66 and 90 hr after feeding and their recovery rates were 0.35 ± 0.10 and 0.65 ± 0.04, respectively. In both feeding trials, the retention time of Cr₂ O₃ was much shorter than that of the termite mandibles and ant head capsules, indicating that Cr₂ O₃ is not an appropriate indicator for estimating food retention time of myrmecophagous animals. Our results revealed that the ant head capsules were preserved better in feces compared with the termite mandibles, suggesting that termites may be considerably underestimated in the feces of wild pangolins.

Topography and syntopy of abdominopelvic viscera of the giant anteater (Myrmecophage tridactyla - Linnaeus, 1758)

ABSTRACT In view of the scarcity of data about the topography and syntopy of abdominopelvic viscera of the giant anteater (Myrmecophage tridactyla - Linnaeus, 1758), the present study aimed to elucidate these characteristics and to compare them with the other animal species, especially the domestic ones. Three specimens, two males and one female, were donated by the Environmental Military Police of Franca to the Anatomy Veterinary Laboratory of the University of Franca, after death by road killings. The animals were fixed and maintained in aqueous 10% formaldehyde solution, followed by conventional dissection of the abdominopelvic cavities for subsequent direct inspection and topographic description of the viscera, aiming at comparative analyzes with other species, whose positioning and particularities are already established in the literature. It was observed that most of the viscera of these cavities have similar location and syntopy to domestic animals, except for the kidneys and testicles. In view of the established methodology and the results obtained, it is accepted that more specimens of anteater, both genera, should be evaluated and registered scientifically to confirm the data of the current research and anatomical preconization of the abdominopelvic cavity, inasmuch anatomical individual variation are possible between animals of the same species.

The addition of soil and chitin into Sunda pangolin (Manis javanica) diets affect digestibility, faecal scoring, mean retention time and body weight

Pangolins (Manis spp.) are myrmecophagous mammals with a wild diet of termites and ants. Diets are not yet readily acceptable by all pangolins and lack soil and chitin compared to their wild diet. This study aimed to assess the usefulness of including soil and chitin in pangolin diets by measuring changes in digestibility, food mean retention time, faecal scoring and body weight changes. Two male and two female Sunda pangolins (Manis javanica) from Night Safari (Singapore) were fed their typical gruel-type diets, with soil and chitin added in various amounts throughout 10 different treatments. Diet intake was calculated daily and faecal boluses were collected for digestibility analysis. Chromium oxide was added to the diet to measure mean retention time four times per animal per treatment. Faecal consistency scores were recorded daily where 1 is firm and 5 is liquid. Every animal was weighed weekly. Adding soil or chitin to the diet had various effects on the apparent digestibility of organic matter, crude protein and fiber with little effects on crude fat or calcium. Soil had a general positive influence on organic matter and fiber digestion. The addition of chitin and soil together had the stronger effects. Only at 25% inclusion of soil did the faecal score begin to improve. The overall maintenance energy requirements for adult M. javanica was 79.28 Kcal/kg BW^0.75 /day, similar to other myrmecophagous mammals. The usage of soil and chitin in pangolin diets may be helpful in controlling weights while preventing behaviours associated with hunger.

Acidic mammalian chitinase gene is highly expressed in the special oxyntic glands of Manis javanica

The Malayan pangolin (Manis javanica) is a mammal that feeds primarily on ants and termites, which contain the energy‐rich carbohydrate chitin. Chitin is digestible by endogenous enzymes of the typical mammalian gastrointestinal tract, especially the acidic mammalian chitinase (AMCase). The objective of this research was to determine whether AMCase activity is expressed in the stomach of M. javanica. The stomach tissues were divided into three parts: the gastric sack, the oxyntic glands, and the pyloric musculature, which were assayed by conventional RT‐PCR, quantitative reverse transcriptase‐coupled PCR (qPCR) and western blot. Information regarding 3D structural models of AMCase was also obtained. In conclusion, acidic mammalian chitinase is highly expressed in the oxyntic glands of the M. javanica species.

Association with humans and seasonality interact to reverse predictions for animal space use

BACKGROUND

Variation in animal space use reflects fitness trade-offs associated with ecological constraints. Associated theories such as the metabolic theory of ecology and the resource dispersion hypothesis generate predictions about what drives variation in animal space use. But, metabolic theory is usually tested in macro-ecological studies and is seldom invoked explicitly in within-species studies. Full evaluation of the resource dispersion hypothesis requires testing in more species. Neither have been evaluated in the context of anthropogenic landscape change.

METHODS

In this study, we used data for banded mongooses (Mungos mungo) in northeastern Botswana, along a gradient of association with humans, to test for effects of space use drivers predicted by these theories. We used Bayesian parameter estimation and inference from linear models to test for seasonal differences in space use metrics and to model seasonal effects of space use drivers.

RESULTS

Results suggest that space use is strongly associated with variation in the level of overlap that mongoose groups have with humans. Seasonality influences this association, reversing seasonal space use predictions historically-accepted by ecologists. We found support for predictions of the metabolic theory when moderated by seasonality, by association with humans and by their interaction. Space use of mongooses living in association with humans was more concentrated in the dry season than the wet season, when historically-accepted ecological theory predicted more dispersed space use. Resource richness factors such as building density were associated with space use only during the dry season. We found negligible support for predictions of the resource dispersion hypothesis in general or for metabolic theory where seasonality and association with humans were not included. For mongooses living in association with humans, space use was not associated with patch dispersion or group size over both seasons.

CONCLUSIONS

In our study, living in association with humans influenced space use patterns that diverged from historically-accepted predictions. There is growing need to explicitly incorporate human-animal interactions into ecological theory and research. Our results and methodology may contribute to understanding effects of anthropogenic landscape change on wildlife populations.

Keeping and breeding the rescued Sunda pangolins (Manis javanica) in captivity

The Sunda pangolin (Manis javanica Desmarest, 1822) is a Critically Endangered species. Given that this species lacks effective policies for in situ conservation and prevention of poaching in the wild, ex situ conservation and a captive breeding program are urgently needed to save this species from extinction. However, techniques for the maintenance and captive breeding of pangolins have not been well developed. In June 2010, we established the Pangolin Research Base for Artificial Rescue and Conservation Breeding of South China Normal University (PRB-SCNU). To date, a total of 34 Sunda pangolin cubs have been born at PRB-SCNU, 26 of which were captive bred, indicating great progress in keeping and breeding the Sunda pangolin. The techniques for maintenance-including housing, transitioning to an artificial diet, husbandry, and captive breeding-are described in this paper. The purpose of this manuscript is to share our successful experiences and techniques in the maintenance, management, and captive breeding of Sunda pangolins, and to provide guidance and a reference for the captive care and management of Sunda pangolins and other pangolin species.