Research Articles (Mammal Research Institute)

Permanent URI for this collectionhttp://hdl.handle.net/2263/5233

A collection containing some of the full text peer-reviewed/ refereed articles published by researchers from the Mammal Research Institute

Browse

Now showing 1 - 20 of 1306

Wild canids and felids differ in their reliance on reused travel routeways
Fagan, William F.; Krishnana, Ananke G.; Fleminga, Christen H.; Ferreira, Elizabeth; Chia, Stephanie; Swain, Anshuman; Abrahms, Briana; Bracis, Chloe; Gurarie, Eliezer; Mueller, Thomas; Noonan, Michael J.; Oliveira-Santos, Luiz Gustavo R.; Tucker, Marlee A.; Anand, Gayatri; Liao, Qianru; Na, Sarah; Su, Steven; Liao, Daisy; Chilukuri , Varun; Ramulu, Shreyas; Diele-Viegas, Luisa Maria; Dougherty, Michael; Illingworth, David; Alexandrov, Dmitry Y.; Antunes, Pamela Castro; Azevedo , Fernanda C.; Barrett, Christina; Barroso, Matías Taborda; Behr, Dominik M.; Belant, Jerrold L.; Bellana, Steven; Berteaux, Dominique; Beyer, Dean E.; Bidner , Laura R.; Bishop, Jacqueline; Blount, J. David; Butler, Andrew; Carter, Andrew; Carvalho, Marina Motta; Chamberlain, Michael; Chistopolova, Maria D.; Clarkmm , Darren; Conner, L. Mike; Cotterill, Alayne; Cozzi, Gabriele; Cristescu, Bogdan; Cunningham, Calum X.; Çoban, Emrah; Darlington, Siobhan; Das Candeias, Ísis Zanini; DePerno, Christopher S.; Dekker, Jasja J.A.; Downs, Colleen T.; Dronova, Natalia; Drouilly, Marine; Eblate, Ernest; Ekwanga, Steve; Swingen , Morgan; Farhadinia, Mohammad; Ford, Adam T.; Frair, Jacqueline; Frank, Laurence; Fryxell, John M.; Fuller, Todd K.; Fyumagwa , Robert; Garthe, Stefan; Getz, Wayne Marcus; Palacios Gonzalez, Maria Jesus; Gooliaff, T.J.; Götz, Malte; Hamer, Rowena; Haberfeld, Mario; Hebblewhite, Mark; Hernandez-Blanco , Jose A.; Herrmann, Mathias; Heurich, Marco; Hodge, Karen E.; Houser, AnnMarie; Humphries, Bruce; López Iglesias, Miguel Ángel López; Isbell, Lynne A.; Jachowski , David; Jackson, Craig; Janssen, René; Jenks, Kate E.; Jiménez, Jaime E.; Jorge, Maria Luisa S.P.; Jorge, Rodrigo; Jubete, Fernando; Katna, Anjan; Kays, Roland; Kittle , Andrew M.; Klein, Rebecca; Kont, Raido; Kral, Michelle J.C.; Kusak, Josip; Lang, Johannes; Latham, Andrew David M.; Leimgruber, Peter; Lemos, Frederico G.; Levi, Taal; Lima , Caio F.M.; Lima, Edson; Lima, Fernando; Linnell, John D.C.; Macdonald, David W.; Mahoney, Peter; Männil, Peep; Masenga, Emmanuel; Mattisson, Jenny; May, Roel F.; McBride Jr., Roy T.; McDonald, Robbie A.; McNutt, J. Weldon; Miller, Karl; Minaev, Alexander; Miquelle, Dale G.; Moorman, Christopher E.; Morato , Ronaldo G.; Moreno, Ricardo; Mourão, Guilherme; Munkhtsog, Bariushaa; Munkhtsog, Bayaraa; Naidenko, Sergey V.; Nava, Teresa; Odden, John; Odden , Morten; Palomares, Francisco; Patterson, Brent R.; Patterson, Bruce D.; De Paula, Rogerio Cunha; Paviolo, Agustin; Petrunenko, Yury K.; Pkhitikov, Alim B.; Poyarkov, Andrey D.; Prugh, Laura R.; Rafiq, Kasim; Ramalho, Emiliano Esterci; Ramesh, Tharmalingam; Ranc, Nathan; Ranglack, Dustin H.; Ratnayaka, Anya; Roshier, David; Røskaft, Eivin; Rozhnov, Viatcheslav V.; Ruiz-Villar, Hector; Ruprecht, Joel; Samelius, Gustaf; Schwemmer, Philipp; Şekercioğlu, Çağan H.; Serieys, Laurel E.K.; Seryodkin, Ivan V.; Simon, Olaf; Songsasen, Nucharin; Sorokin, Pavel A.; Soutryina, Svetlana; Stent, Patrick; Stoner, David; Streicher, Jarryd; Tatler, Jack; Teichman, Kristine; Thaker, Maria; Thompsona , Katerina V.; Thompson, Jeffrey J.; Tortato, Marcos Adriano; Trinzen, Manfred; Van Der Weyde, Leanne; Vanak, Abi Tamim; Velilla, Marianela; Walton mmmmmm , fffff , sss , nnnnnn, , Zea; Wheeldon, Tyler J.; Tomas Willebrand; Williams, Terrie M.; Wilmers, Christopher C.; Wilson-Aggarwal , Jared; Wyson, Michael L.; Yachmennikova, Anna A.; Young, Julie K.; Calabrese, Justin M. (National Academy of Sciences, 2025-09-29)
Diverse factors, including environmental features and cognitive processes, can drive animals’ movements and space use, with far-reaching implications. For example, repeated use of individual-level travel routeways (directionally constrained but imperfectly aligned routes), which results in spatial concentration of activity, can shape encounter-based processes including predation, mate finding, and disease transmission. However, how much variation in routeway usage exists across species remains unknown. By analyzing GPS movement tracks for 1,239 range-resident mammalian carnivores—representing 16 canid and 18 felid species from six continents—we found strong evidence of a clade-level difference in species’ reliance on repeatedly used travel routeways. Across the global dataset, tracked canids had a 15% (±7 CI) greater density of routeways within their home ranges than did felids, rising to 33% (±16 CI) greater in landscapes shared with tracked felids. Moreover, comparisons within species across landscapes revealed broadly similar home range routeway densities despite habitat differences. On average, canids also reused their travel routeways more intensively than did felids, with hunting strategies and spatial contexts also contributing to the intensity of routeway usage. Collectively, our results suggest that key aspects of carnivore routeway-usage have an evolutionary component. Striking interspecific and clade-level differences in carnivores’ reliance on reused travel routeways within home ranges identify important ways in which the movement patterns of real-world predators depart from classical assumptions of predator-prey theory. Because such departures can drive key aspects of human-wildlife interactions and other encounter-based processes, continued investigations of the relationships between movement mechanisms and space use are critical.
Precocial weaning influences anxiety, social and maternal care but not cognition in African striped mice, Rhabdomys dilectus chakae
Oosthuizen, Maria Kathleen; Pillay, Neville (Wiley, 2026-03)
Weaning is a stressful stage in the lives of young mammals. Early weaning, in particular, can lead to long-lasting physiological and psychological changes. We investigated the effects of precocial weaning on anxiety, social behavior, cognition, and maternal behavior in adult African four-striped mice (Rhabdomys dilectus chakae). Mice weaned at 12 days exhibited higher anxiety levels and reduced exploratory behavior in a novel environment compared with those weaned at 16 and 20 days. Early-weaned mice also showed decreased allogrooming and body contact, and increased aggression during social interactions. Females weaned early, groomed, and huddled their pups less, although they spent more time in proximity without touching their pups. Spatial learning and memory were not affected by the age at weaning. Early weaning induces stress-related changes in anxiety, exploration, and social behaviors, all of which are of ecological relevance. Although precocious weaning did not affect cognition, R. d. chakae are likely to be anxious and poor mothers, which could also impact the fitness of their offspring. These effects manifested in behaviors of ecological significance, suggesting that early weaning may influence the fitness of the four-striped mouse
Characterising the gut microbiomes of two baleen whales with different feeding and migratory strategies
Parikh, Aashi; O’Rorke, Richard; Carroll, Emma L.; Vermeulen, Els; Harcourt, Robert; Constantine, Rochelle; Plon, Stephanie; Rayment, William J.; Chariton, Anthony (BioMed Central, 2026-03-12)
BACKGROUND: Mammalian gut microbiomes are essential for supporting digestion, nutrient absorption and overall host health. While diet and phylogeny are the two main influences on gut microbial composition, other factors, including life history and environment also contribute. Here, we characterised and compared the gut (faecal) bacterial microbiomes of two baleen whale species with contrasting life histories: the Bryde’s whale (Balaenoptera edeni brydei), a non-migratory, year-round generalist forager; and the southern right whale (Eubalaena australis; SRW), a seasonal migrating species with a specialised diet of krill and copepods. RESULTS: We found that each species harboured distinct gut microbiomes with potential links to their different feeding and migratory strategies. The Bryde’s whale gut microbiome bore a strong resemblance to that of toothed whales, with relatively lower bacterial richness and diversity and a high proportion of Proteobacteria after Firmicutes. The core microbiome of these whales included taxa supporting a protein-rich diet and year-round foraging lifestyle, e.g. Carnobacterium and Faecalitalea. In contrast, the SRW had a gut microbiome similar to other baleen whale species, with a higher richness and diversity, and dominated by Firmicutes and Bacteroidetes. The SRW core microbiome featured taxa associated with lipid metabolism, e.g. Erysipelotrichaceae and Coriobacteriia, reflecting a lipid-rich diet and reliance on blubber reserves during migration. We also found that SRWs sampled at different stages in the migratory cycle had significantly different gut microbial compositions. Functional analyses further supported these results, with Bryde’s whales being broadly enriched in enzymatic functions including protein digestion and SRWs showing more selective enrichment. CONCLUSIONS: Along with species-specific microbiomes, our findings also suggest that migratory behaviour and foraging patterns – key aspects of cetacean life history – may substantially influence gut microbiome composition. The characterisation of the gut microbiomes of the two whales provides a valuable baseline for the future monitoring of cetaceans and their environments.
Going big : home ranges of translocated leopards in the Central Bushveld of the North West Province
Venter, Leanne; Power, Richard John; De Crom, Engela P.; Reilly, Brian Kevin; Scheun, Juan (Southern African Wildlife Management Association, 2025)
Home ranges are crucial for terrestrial wildlife as they define the spatial area where individuals satisfy their ecological needs, including foraging, mating, and shelter (Powell & Mitchell, 2012). Establishing and maintaining home ranges contribute to population dynamics, resource partitioning, and overall habitat utilization, influencing the species’ reproductive success and survival (Maher & Lott, 2000). The evolution of home ranges in terrestrial species is intricately tied to ecological and environmental factors, shaped by selective pressures over generations (Mazzamuto et al., 2020); primary drivers of a home-range characteristic include factors such as resource availability, body mass and social dynamics (Campos et al., 2014; Rodríguez-Recio et al., 2022).
Ecological factors rather than tourism pressure primarily affect the stress-related endocrine response of four ubiquitous mammal species in a small South African reserve
Crossey, Bruce Gareth; Pienaar, Elizabeth Frances; Ganswindt, Andre (NISC (Pty) Ltd and Informa UK Limited (trading as Taylor and Francis Group), 2026-06)
Wildlife tourism is a growing global industry with notable economic and conservation value, yet its potential impact on animal welfare is a critical concern. Traditional behavioural studies have been used to assess these effects, but non-invasive physiological measures, such as faecal glucocorticoid metabolites (fGCMs), provide direct insight into stress-related coping mechanisms. This study presents a multispecies assessment of fGCM alterations associated with tourism and season in four ungulates—impala (Aepyceros melampus), zebra (Equus quagga), blue wildebeest (Connochaetes taurinus) and giraffe (Giraffa camelopardalis)—within a small South African nature reserve. Using established species-specific enzyme immunoassays, 533 faecal samples collected during the wet and dry seasons were analysed, considering season, sex and tourist activity levels. The results revealed species-specific endocrine responses primarily to ecological factors, but also in some cases to anthropogenic factors. Blue wildebeest showed elevated fGCMs during the wet season, likely linked to reproductive events and social changes. Zebra and impala exhibited higher fGCMs during the dry season, coinciding with resource scarcity and increased tourism, with impala fGCMs significantly higher on weekends, suggesting an interaction between ecological and tourism-related stressors. Giraffe showed no seasonal or tourism-related effects, although females had higher fGCMs, likely reflecting pregnancy-related endocrine changes. These findings underscore the value of a multispecies approach to evaluate physiological impacts of wildlife tourism. Identifying differential sensitivities among species highlights the need for tailored management strategies to minimise welfare impacts, particularly during ecologically sensitive periods. As nature-based tourism expands, evidence-based practices will be essential to balance visitor experiences with conservation and animal welfare objectives.
Unravelling taxonomic complexity in elusive cetaceans : mitogenome insights into evolutionary history and cryptic diversity of Bryde's whales
Paynee, Dominique Kelsi; Bloomer, Paulette; Penry, Gwenith S.; Elwen, Simon; Natoli, Ada; Dhanalakshmy, Vaisakh; Cardoso, Thyago; Vermeulen, Els (Wiley, 2026-05)
Cetaceans, despite their ability to cross wide distances, enabling mostly high levels of gene flow, can develop unique genetic lineages driven by variations in life-history traits, diverse migratory routes and local adaptation, complicating taxonomy and delineation of conservation units. Comprehensive genetic data are essential to overcome the challenges of obtaining suitable sample sizes from wild cetaceans while untangling cryptic species diversity. The Bryde's whale (Balaenoptera edeni) has a complicated discovery and taxonomic history that hinders accurate conservation assessments. In southern Africa, two populations are recognised: the inshore (SAi) and the offshore southeast Atlantic population (SEA). This study examines their phylogenetic relationships and evolutionary history relative to global populations and other balaenopterids. Complete mitochondrial genomes from SAi and SEA individuals were analysed alongside mitogenomes from the Arabian/Persian Gulf (United Arab Emirates, UAE, this study), North Pacific offshore ecotypes (GenBank), coastal Japan's inshore ecotype (GenBank) and five additional balaenopterid species (GenBank). Phylogenomic analyses revealed that each population forms a distinct lineage. SAi and SEA individuals grouped with the subspecies B. edeni brydei (offshore ecotype), despite the SAi occurring inshore, whereas the UAE individual was more closely related to B. edeni edeni and B. ricei. Divergence dating estimates suggest that the southern African, UAE and North Pacific populations shared a most recent common ancestor approximately 4–5 million years ago. These findings emphasise the need to reassess conservation units, population estimates and potentially reclassify new subspecies or species among Bryde's whales. This study demonstrates how mitogenome data can detect cryptic diversity in elusive cetaceans, directing more effective conservation of unique genetic lineages
DNA metabarcoding reveals unexpected predator-prey-microbial dynamics in the southern right whale (Eubalaena australis)
Parikh, Aashi; O'Rorke, Richard; Carroll, Emma L.; Vermeulen, Els; Harcourt, Robert; Plon, Stephanie; Rayment, William J.; Chariton, Anthony (Wiley, 2026-06)
Southern right whale (Eubalaena australis; SRW) populations are recovering from the impacts of commercial whaling, however, recovery has been spatially variable, with strong associations between reproduction and prey availability. The diet of SRWs has not been widely examined, and with SRW foraging shifting away from high-latitude foraging grounds dominated by krill, it is essential to understand their diet at different locations. The gut microbiome is closely linked to diet, and characterising gut bacterial composition can help evaluate long-term changes in prey and ecosystem dynamics. We used DNA metabarcoding to characterise the diet and faecal microbiome of SRWs from three calving/socialising grounds and a low-latitude foraging ground. SRW feeding was more opportunistic than previously documented. Decapoda emerged as a key component of the SRW diet, being consistently detected at higher frequency and relative read abundance than euphausiids and copepods in whales from both calving/socialising and foraging grounds. The expected prey of Calanoida were also prominent in whales from the foraging ground, as were Stomatopoda, Cumacea and Semaeostomeae. A significant correlation between diet composition and faecal bacterial composition was observed, with euphausiids being the strongest predictor of bacterial variation. Our findings provide a new understanding of the breadth and diversity of the diet of SRWs. We also provide a baseline for monitoring diet–gut microbiome interactions. Collectively, these results offer a glimpse into the trophic dynamics of a Southern Ocean predator being impacted by climate-driven changes in zooplankton distribution, with implications for long-term population recovery.
Using stable isotopes to investigate the seasonal diet of Southern African rodents across natural and peri-urban landscapes
Ramahlo, Mmatsawela; Somers, Michael J.; Ganswindt, Andre; Hall, Grant (Springer, 2026-05)
Dietary studies on wildlife using minimally invasive techniques can elucidate the impacts of anthropogenic activities on ecosystems and native species. Investigating diet-related resource partitioning of biological indicator species can improve our understanding of mechanisms employed by animals to survive in a rapidly changing world. We compared carbon (δ13C) and nitrogen (δ15N) isotope ratios from hair tissue of four dominant southern African rodent species from the Magaliesberg Biosphere, North West province, South Africa. Hair was collected over three years during both dry and wet seasons across different land-use types: natural and peri-urban. There was significant isotopic variation between the four species across land-use types and seasons. Pairwise post-hoc comparisons of within-site diet proportions showed increased homogeneity of two synanthropic species (Lemniscomys rosalia and Mastomys coucha) in the peri-urban site, suggesting exploitation of robust, low-quality grasses and grains. Niche overlap was significantly variable between seasons at the peri-urban site, with an increased intake in grasses and maize grains during the planting and growing wet season, suggesting the rodents are more selective with increased food availability. During the dry season, food sources were shared by two non-commensal species (Aethomys ineptus and Micaelamys namaquensis), and the two synanthropic species shared three food sources. Overall seasonal variation across sites may indicate variable diet plasticity in the four generalist species, but specialists in increasingly encroached upon and urbanized seasonal landscapes may struggle to adapt to available food and face extirpation.
Evaluation of mammalian endurance using accelerometry in natura : bridging exercise physiology and ecology
Rozier-Delgado, Pablo; Vonderscher, Mylene; Blervaque, Leo; Brivio, Francesca; Buuveibaatar, Bayarbaatar; Chamaillé-Jammes, Simon; Ciuti, Simone; Christe, Philippe; English, Holly M.; Eriksen, Ane; Fillon, Aurelie; Grignolio, Stefano; Jego, Florence; Kaczensky, Petra; Latini, Roberta; Libourel, Paul-Antoine; Lorand, Charlotte; Marchand, Pascal; Marques, Nathalie; Nivois, Eveline; Pisicchio, Enzo; Surer, Philippine; Valeix, Marion; Zimmermann, Fridolin; Gaillard, Jean-Michel; Garel, Mathieu; Loison, Anne; Morel, Baptiste (Company of Biologists, 2026-04)
Please read abstract in the article.
Human activity, including tourism, increases stress and influences breeding location choice in wild tigers in India
Khan, Aamer Sohel; Kumar, Vinod; Anusha, Gudimella; Ganswindt, Andre; Umapathy, Govindhaswamy (Wiley, 2026)
Wildlife tourism is increasing globally, with a growing proportion of activities occurring in protected areas that help them generate significant revenue. Consequently, management authorities must integrate tourism into conservation planning. Such rise in human activity in these areas can adversely affect wildlife behaviour, physiology, and reproduction. A better understanding of the impact of wildlife tourism on tiger wellbeing and spatial behaviour is therefore critical for the sustainable management of these populations. We studied the effects of wildlife tourism and anthropogenic activities on stress and reproductive physiology in wild tigers across five reserves in India. We quantified faecal glucocorticoid metabolites (fGCMs), a biomarker of stress, and faecal progesterone metabolites (fPMs), an indicator of breeding activity in females. We collected 728 presumptive tiger scat samples from core and buffer zones during both tourism and non-tourism seasons, which encompass breeding periods. Genetic analysis confirmed that 610 samples originated from tigers; these were sexed and analyzed for fGCM and fPM levels. Our findings indicate that tigers exhibited higher fGCM levels in areas with high anthropogenic activity. Further, we observed spatial variation in fGCM levels that correlated with patterns of human disturbance, including tourism, suggesting a heterogeneous distribution of stressors. As human disturbance intensified in core zones, tiger fGCM levels increased and were negatively correlated with proximity to tourism roads. Furthermore, among the areas surveyed, tigresses exhibited higher fPM levels in certain locations of the reserves, where they experienced lower fGCM levels compared to other locations. This may indicate that tigresses potentially choose locations with less disturbance for breeding. Based on these results, we discuss potential management strategies to mitigate the impact of human activities on tigers and support their reproduction.
Reevaluating introduced herbivores in conservation
Trepel, Jonas; Buitenwerf, Robert; Ferraro, Kristy; Le Roux, Elizabeth; Lundgren, Erick; Maitner, Brian; Strydom, Tanya; Svenning, Jens-Christian; Kerr, Matthew R. (Wiley, 2026)
The impacts of non-native species are the subject of enduring controversy in conservation research and policy. This debate has renewed relevance in light of rewilding approaches that introduce or reintroduce herbivores to restore trophic complexity. However, because large herbivores inherently have strong effects, recent work has warned that the “harms of introduced large herbivores outweigh their benefits” (Bescond-Michel et al., 2025; Nogués-Bravo et al., 2016; Nores et al., 2024). We argue that such conclusions are conceptually and methodologically flawed, particularly because they conflate the predictable consequences of herbivory with harmfulness attributed to a species' non-native status. Without assessing whether effects of non-native herbivores differ from those of native herbivores, these approaches risk depicting the fundamental process of herbivory as problematic. This can misinform conservation and restoration efforts at a time when herbivores, native or introduced, are increasingly recognized as essential for sustaining biodiversity and ecosystem function (Lundgren et al., 2018; Malhi et al., 2016; Pringle et al., 2023; Smith et al., 2016; Svenning et al., 2024; Trepel et al., 2024). ARTICLE IMPACT STATEMENT : Herbivory is a fundamental ecological process; treating it as harm misinforms conservation decisions about introduced herbivores.
Seabird assemblages, abundance, and distribution in the African sector of the southern Indian Ocean
Makhado, A.B.; Dakwa, F.E.; Ryan, P.G.; Masotla, M.J.; Dyer, B.M.; Seakamela, S.M.; Shabangu, Fannie Welcome; Somhlaba, S.; Reisinger, R.R. (Comm. for the Conserv. of Antartic Marine Living Resources, 2025)
ABSTRACT : Seabird distributions in the Southern Ocean are influenced by the location and accessibility of suitable breeding sites, but also by the environmental factors that influence the distribution and availability of their prey. For example, oceanic fronts, concentrate prey at their surface and therefore present important foraging areas for many seabirds. This study investigated the latitudinal distribution and abundance of seabirds in the African sector of the Southern Ocean. In particular, we investigated the relationship of seabird assemblages and densities to key biophysical environmental parameters (SST, sea surface height, bathymetry) and the main oceanic fronts. There was a high density of seabirds north of the Subtropical Convergence (STC), which is situated at approximately 39°S, with declining densities farther south. There was latitudinal segregation between several species, e.g. black-browed albatross (Thalassarche melanophris) occurred north of the STC, and grey-headed albatross (T. chrysostoma) occurred to south of it. The Subantarctic Front (SAF) and the Antarctic Polar Front (APF) had less influence on seabird populations than the STC. Latitude was the greatest predictor of seabird assemblages and densities, reflecting environmental gradients in physical and biological parameters and their influences on prey distributions. Of the environmental parameters, sea surface temperature and bathymetry were the most important physical features influencing seabird assemblages. In particular, the density of seabirds north of STC declined with increasing sea surface temperature and had a negative relationship with bathymetry, with most seabirds occurring in shallower waters. In contrast, seabird density had a positive linear relationship with sea surface height. Relationships with other environmental parameters, such as wind, salinity and chlorophyll concentration (as a proxy for productivity), were less well-defined.
Exploring techniques to assess stress-related physiological responses in captive African penguins
Currin, Cat; Ganswindt, Andre; Pichegru, Lorien (Elsevier, 2026-06)
As animals experience a range of stressors, monitoring their stress response is important in conservation management and animal welfare practices. This study investigated possible techniques for evaluating stress-response in captive African penguins (Spheniscus demersus), including recording heart rate (HR) with a novel recorder inside a dummy egg, quantifying glucocorticoids in serum (sGC) and feathers (fGC) and glucocorticoid metabolites (ufGCM) in urofaeces. ● The HR recorders allowed for an assessment of immediate responses to stressors, however improvements in the design are necessary to record more consistent HR data. ● SGCs provide an assessment of an immediate stress response to acute stressors, however, due to the invasive nature of sampling this technique should only be used when blood is being drawn for medical reasons. UfGCM concentrations are less sensitive to short-term perturbations due to the accumulation of GC metabolites over longer periods, and due to the minimally invasive sampling procedure, allow for resampling, providing a useful tool for assessing long-term stress-related physiological response and welfare. FGC concentrations represent an integration of hypothalamic pituitary-adrenal activity over a period of days/weeks, however, whether this reflects circulating baseline levels or significant stressful events during feather growth is unclear and further research is needed to determine this.
Tracking data reveal both indirect and direct interactions between killer whales and fisheries in subantarctic waters
Robert, Vinicius; Laurioux, Anais; Reisinger, Ryan Rudolf; Towers, Jared R.; Auguin, Erwan; Mollier, Margaux; Richard, Gaetan; De Bruyn, P.J. Nico; Guinet, Christophe; Tixier, Paul (Elsevier, 2026-05)
Conflicts between large marine predators and fisheries often involve both indirect (competition for fish stocks) and direct negative interactions (bycatch or depredation). However, the extent and the mechanisms of these conflicts are hampered by lack of data on the behavior of predators in natural situations (absence of fishing vessels) and in response to fishing activities. For killer whales Orcinus orca in the remote subantarctic waters of the southern South Atlantic and Indian Oceans, this lack of understanding is particularly problematic since negative interactions with industrial fisheries targeting toothfish affect the conservation of populations. In this study, we combined data from 36 satellite tags deployed on killer whales in these regions between 2011 and 2024 with tracking (AIS) data of toothfish fishing vessels to i) assess the overlap between killer whale offshore foraging areas and fishing areas, and ii) examine the factors influencing the decision of individuals to engage in depredation. Through kernel utilization distributions and statistical models we show that killer whales foraged in offshore areas used by fishing vessels to catch toothfish, but this overlap varied greatly across individuals within populations. We found that killer whales changed their trajectories and headed toward fishing vessels as far as > 100 km from them, possibly to engage in depredation. However, this behavior was not systematic and differed across individuals and areas. The behavior was detected only 55% of the times killer whales entered a 60 km range from a vessel. By highlighting areas of co-occurrence of killer whales and fisheries and the extent to which killer whales are able to change their behavior in response to fishing activities, our findings provide information that can be used to mitigate the negative impacts of interactions.
Evolutionary and ecological determinants of the phenology of births in wild large herbivores, a systematic review
Thel, Lucie; Bonenfant, Christophe; Chamaillé-Jammes, Simon (Wiley, 2026-06)
INTRODUCTION : Timing of birth is a major determinant of individuals' reproductive success and phenotypic performances, driven by multiple factors. However, there is currently no quantitative assessment of the support received by the drivers of the phenology of births in wild mammals. AIMS : Our objective was to identify the drivers tested for their effect on the phenology of births in large herbivores and how much empirical support they received, as well as determine thematic, taxonomic and spatial gaps in the literature. METHODS : We conducted a systematic review focusing on the drivers of the phenology of births in large herbivores. We extracted the outcomes of 124 articles and assessed the reliability of their findings using a general index based on the quality of the data and methods used. RESULTS AND DISCUSSION : We identified a major research gap in Asian and South and Central American species. The effect of population and individual characteristics remained marginally accounted for, even though there was evidence of their importance in the determination of the phenology of births. The two dominant hypotheses (seasonality and predation) received good to moderate empirical support regarding their effect on birth timing and synchrony, respectively. Given the strong geographic and methodological biases, these hypotheses should be considered as most consistently supported in the existing literature rather than definitively established across systems. CONCLUSIONS : We encourage research in these understudied domains, as well as large scale multi-species comparative analyses to fill in these gaps and improve our understanding of reproductive phenology.
Temporal change in the diet of Tyto alba (barn owl) near a Natal long-fingered bat (Miniopterus natalensis) maternity roost in Limpopo province, South Africa
Swartz, Emma; Kearney, Teresa; Seamark, E.C.J.; Keith, Mark (Ditsong National Museum of Natural History, 2025)
Regurgitated pellets of Tyto alba (barn owls) are useful in determining small mammal communities. This study examines variation in the diet of T. alba in relation to an increase in abundance of a migratory bat, Miniopterus natalensis. An estimated 150 000–200 000 Min. natalensis migrate into the study cave (Madimatle Cave) during October–November to give birth. We hypothesised that this bat would predominate in the diet of T. alba when the abundance of this bat was highest. Relative abundance for Min. natalensis, and other bats, was obtained using a bat-detector station located 600 m from the cave entrance and 70 m from an owl roost. Tyto alba pellets were collected at the roost on five sample occasions over eight months between November 2016 and May 2017.Each pellet was dissected, and its contents were recorded. Sixty-four pellets were analysed, the contents of which were 43.5% arthropods and 56.5% mammals, with no birds or herpetofauna. Fourteen mammal species were recorded. Two shrew species (Suncus lixus and Suncus varilla) were recorded for the first time in the area. A significant positive relationship (P = 0.006)was found between the abundance of Min. natalensis in the cave system and the diet of T. alba over the period sampled. This suggests that when the large numbers of Min. natalensis females and young are present at Madimatle Cave T. alba diet selection was determined more by prey abundance than preference.
Environmental education positively impacts the perceptions of learners towards bats in schools in a low socio-economic area in South Africa
Mdluli , Veli Monday; Howard, Alexandra; Bredenhand, Emile Bredenhand; Monadjem, Ara; Dube, Bekithemba; Rakotoarivelo, Adrinajoro; Taylor, Peter John (Public Library of Science, 2025-12-19)
Bats are amongst the most important ecosystem service providers in the world. This is in part due to their diversity as they are the second largest group of mammals with a widespread global distribution. Despite this, most cultures around the world have negative stereotypes towards bats, largely influenced by myths and beliefs stemming from misconceptions about them. In this study, we aimed to assess the impact of environmental education on enhancing awareness and positive perceptions towards bats and their natural ecosystem services by school learners of ages 11–18 years old in QwaQwa, in the eastern Free State Province of South Africa. Our study addressed negative stereotypes about bats through informed and interactive engagement of scientific and public communication in schools with the use of bat awareness classes, posters, a children’s book on bats, and engagement in bat research revolving around bat boxes installed at each school. We used a standardized questionnaire to assess individual attitudes towards bats pre- and post-intervention, targeting for each survey approximately 200 learners from two primary and one secondary schools in QwaQwa. The perceptions of students were divided into six categories namely scientistic, positivistic, behavioral negativistic, emotional negativistic, cognitive negativistic and myth categories. The intervention resulted in a significant change in negative perceptions of students towards bats for all categories, becoming more positive. We also found gender and age to be important influencers of perceptions for some of the categories. Considering the findings, we argued that intervention through environmental education can be a useful tool for changing negative perceptions of learners towards bats in local South African communities.
Cave dependency limits climate-driven range shifts in African cave-roosting bats
Pretorius, Mariette Estelle; Keith, Mark (Wiley, 2026-05)
Climate and land-use change threaten the persistence of Africa's cave-roosting bats, yet their future distributions remain poorly understood. We present the first continental-scale assessment of climate-driven range shifts for cave-dwelling bats in sub-Saharan Africa, using Miniopteridae as an obligate cave-dependent model taxon, by integrating species distribution models with a validated karst-based roost suitability layer and a landscape-stability index reflecting projected land-cover vulnerability. Using 551 curated occurrence records, MaxEnt models under six CMIP6 climate scenarios projected substantial range contractions of 36%–64% by 2061–2080, with future suitability restricted mainly to southern Africa, the eastern highlands, and Madagascar. Geological constraints further limited persistence: only ~5% of roost-suitable karst overlapped with future climatically suitable areas, and this overlap decreased to ~2% after weighting for land-cover vulnerability. Similarity metrics revealed extremely low spatial congruence between roost availability and stable climatic refugia. Migration ecology suggests that fragmentation of seasonal roost networks may further hinder persistence by disrupting movement corridors and increasing energetic costs. Collectively, these results show that long-term persistence of cave-dwelling species like Miniopteridae will depend on conserving climate–karst refugia and maintaining connectivity between seasonal roosts.
Maternal androgens shape vocal begging patterns in meerkats, providing competitive advantages in dominant matrilines
Walkenhorst, Britta; Goncalves, Ines Braga; Drea, Christine M.; Manser, Marta B. (Elsevier, 2026-05)
Maternal effects provide a non-genomic pathway by which individual phenotypes shape offspring traits. Consistent with this phenomenon, we previously found that socially and experimentally mediated variation in maternal androgen action in the meerkat (Suricata suricatta) – a female-dominant, cooperatively breeding mongoose – influenced the developmental pace of offspring vocalisations, with increased prenatal androgen exposure accelerating their transition between different call types. Here, we test for effects on the fine-scale, temporal structure of two types of begging vocalisations: repeat and digging calls. We measured call durations, inter-call intervals, and call rates in offspring of dominant control (DC; high-testosterone), subordinate control (SC; lower-testosterone), and dominant treated (DT; blocked-testosterone) females, that had received an antiandrogen during late gestation. DC offspring, especially daughters, displayed the most intense begging, producing calls at the highest rates and with the shortest intervals, potentially enhancing the caller's likelihood of being provisioned; DC daughters also showed the steepest decline in call intensity whilst learning to forage. Conversely, SC and DT offspring displayed less intense, potentially less effective, calls that may have delayed nutritional independence. These intergenerational effects show that maternal androgens can mediate resource acquisition strategies by modifying the temporal structure of begging vocalisations in a wild mammal. Moreover, these competitive advantages were reinforced along dominant matrilines, most notably among daughters, offering new insights into the evolutionary significance of female hormonal ‘masculinisation’. HIGHLIGHTS • Maternal androgens mediate vocal begging strategies in meerkat pups. • Offspring of high-testosterone (T) dominant mothers beg most intensely. • Pup calls from lower-T subordinate and blocked-T dominant mothers differ by sex. • Status-related variation in maternal androgens affects daughters more than sons. • High prenatal androgens confer competitive advantage for early resource acquisition.
Daily activity patterns of a near-threatened endemic wetland specialist, the Southern African vlei rat (Otomys auratus)
Webber, Joshua S.; Oosthuizen, Maria Kathleen (Elsevier, 2025-04)
The genus Otomys exhibits diverse activity patterns in the field, making them ideal subjects for studying circadian biology. The Southern African vlei rat (Otomys auratus) has previously been categorised as diurnal or crepuscular, but also displays some nocturnal activity. This study aimed to confirm the temporal niche of vlei rats in a laboratory setting and examine changes in activity when provided with a running wheel. The length of the free-running period was also calculated. In this study, 75 % of vlei rats displayed nocturnal activity rhythms when housed without a wheel. Access to a running wheel reduced individual variation and led to an increase in overall activity counts. All individuals had free running rhythms in constant darkness, with a period shorter than 24 h, which is consistent with other nocturnal rodents. This demonstrates that vlei rats are more active in darker conditions, likely as a means of avoiding diurnal avian predators in wetland habitats. With this species at risk of local extinction, this study is an important first step in understanding the behaviour of vlei rats under controlled conditions. As this species is displaced when its habitat becomes disturbed it may act as a useful bioindicator of wetland health and disturbance level.

Browse

Recent Submissions