Research Articles (Mammal Research Institute)

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

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Whale killers on the coast of South Africa : killer whale predation on a humpback whale super-group
Seyboth, Elisa; Wilkinson, Christopher; Elwen, Simon Harvey; Barnes, A.; Vermeulen, Els (NISC (Pty) Ltd and Informa UK Limited (trading as Taylor and Francis Group), 2026-06)
In December 2023, a pod of 15–20 killer whales Orcinus orca successfully predated on a likely juvenile (∼10-m long) humpback whale Megaptera novaeangliae that was part of a super-group (defined as feeding groups of 20+ individuals close to each other) on the west coast of South Africa. The event was recorded and photographed in detail by researchers from the University of Pretoria from a 6-m-long semi-rigid research vessel. The killer whales exhibited clear predation behaviour, with females and juveniles trying to drown the humpback whale by pressing their bodies on top of it to prevent it from breathing. Roughly one hour later, two additional male killer whales, which had not been active in the predation event up to this point, joined the pod and had a role in the final killing of the humpback whale. The kill occurred underwater and was inferred to have happened as pieces of blubber floated to the surface approximately a minute after the two males joined the pod. As humpback whales recover from whaling, and because super-groups of the species seem to use the west coast of South Africa over multiple months of the year, interactions between humpback whales and killer whales are likely to become more common.
Metabolic acclimation to captivity in highveld mole-rats (Cryptomys hottentotus pretoriae) is driven by sex-specific body mass increases
Thirkell, Jack E.; Bennett, Nigel Charles; Hart, Daniel William; Faulkes, Chris G.; Daley, Monica A.; White, Craig R.; Portugal, Steven J. (Company of Biologists, 2026-05)
Captivity represents a profound environmental shift that can induce physiological acclimation, yet its effects on metabolic rate remain poorly resolved, particularly in subterranean mammals. African mole-rats (Bathyergidae) are frequently studied under captive conditions, despite wide variation in acclimation periods prior to metabolic assessment. Here, we tested whether prolonged captivity alters resting metabolic rate (RMR) and related physiological traits in the highveld mole-rat Cryptomys hottentotus pretoriae, and whether such changes are associated with body mass and sex. Using open-flow respirometry, we measured RMR, mass-specific RMR (msRMR) and respiratory quotient (RQ) in the same population of wild-caught animals assessed 7 days post-capture (wild) and again after 12 months in captivity (captive). Whole-animal RMR did not differ between wild and captive groups, nor between sexes. However, msRMR was 26.1% lower following captivity, coincident with a 28.1% increase in mean body mass. This mass gain was strongly sex specific: males increased body mass by 52.4%, whereas females showed no significant change. Despite this, sex did not independently explain variation in RMR or msRMR. Captive animals also exhibited lower RQ values than recently captured individuals, suggesting shifts in substrate utilisation or energetic state. Together, these results indicate that apparent reductions in msRMR following captivity are driven primarily by increases in metabolically inactive tissue rather than suppression of whole-animal metabolic rate. Our findings highlight the importance of accounting for captivity-induced changes in body mass and composition when interpreting metabolic data, and caution against direct comparisons between unacclimated and long-term captive animals.
Allometric scaling and social modulation of resting metabolic rate in a eusocial mammal (Heterocephalus glaber)
Thirkell, Jack E.; Faulkes, Chris G.; Merchant, Hana N.; Gilbert, James D.; Bennett, Nigel Charles; Hart, Daniel William; Daley, Monica A.; Portugal, Steven J. (Company of Biologists, 2026-06)
Resting metabolic rate (RMR) underpins energy allocation to survival, reproduction, and longevity, yet its drivers in highly structured social systems remain unclear. We measured RMR in 76 naked mole-rats (Heterocephalus glaber) from five colonies to test effects of body mass, sex, reproductive status, age, social rank, and colony stability in this eusocial mammal. Body mass was the strongest predictor of RMR. Nevertheless, absolute RMR values were far below those predicted for mammals of similar mass, confirming metabolic suppression in this strictly subterranean species. Social factors produced subtler patterns. Among non-breeders, males had slightly higher (but not significantly so) RMR than females despite similar body mass. Breeding females showed elevated RMR relative to non-breeding females, but not significantly so. Age and dominance rank did not influence RMR once body mass was controlled. Colony identity explained little variation overall, although one colony showed altered metabolic scaling after social conflict, suggesting colony-level metabolic plasticity associated with hierarchical instability.
Dominance asymmetries shape vocal exchanges in meerkats
Demartsev, Vlad; Gall, Gabriella E.C.; Strandburg-Peshkin, Ariana; Manser, Marta B. (Oxford University Press, 2026-03)
Physical grooming is often used to maintain social bonds in animal groups, but opportunities to groom every group member may be limited. Vocal exchanges may provide an alternative way to sustain social ties without physical proximity. To explore the link between vocal exchanges and social relationships, we examined how dominance and dyadic bond strength influence the intensity of vocal interaction in meerkats (Suricata suricatta). Focusing on “sunning calls”, socially facilitated vocalizations produced when meerkats warm themselves in the sun, we conducted experiments in which we played sunning calls to individuals and recorded their responses. Overall, subordinate individuals increased their call rate in response to dominant calls, whereas dominant receivers showed little or no change. The effect of tie strength was weak overall but varied across dyad types, tending to be negative in dominant–subordinate pairs and slightly positive among subordinates. These results support the notion that sunning calls serve a social regulatory function, possibly acting as bonding or appeasing signals primarily directed toward dominants. The asymmetry between dominant and subordinate responses highlights the strategic nature of social relationships within a despotic society. Engaging in continuous reciprocal interactions may promote tolerance and reduce conflict; thus, investing in such interactions with influential dominants would align with the “vocal grooming” function of these exchanges. Future studies that causally link vocal interactions to long-term relationship outcomes will be key to understanding how such vocal exchanges complement physical affiliation across species.
Translocation of livestock-raiding lions under specific conditions can mitigate conflict
Briers-Louw, Willem D.; Almeida, Joao; Pereira, Carlos Lopes; Pereira, Hugo; Chiponde, Hagnesio; Lindsey, Peter Andrew; Kendon, Tamar A.; Ngalijuane, Dario; Rosier, Holly; Taylor, Jo; Worth, Ellery; Roodbol, Marnus; Manhica, Eugenio; Gaynor, David; Leslie, Alison; Naude, Vincent N. (Wiley, 2026)
Human–wildlife conflict continues to threaten the persistence of large carnivores, with livestock depredation by lions (Panthera leo) often resulting in lethal control. Translocation is widely dismissed as ineffective, yet few empirical assessments have tested its efficacy under favorable ecological and management conditions. We report on “reactive” (n = 4) and “strategic” (n = 5) translocations of livestock-raiding lions within Mozambique between 2020 and 2024. Based on our criteria, none of the reactive translocations were confirmed as successful outcomes; 50% failed outright due to conflict lions returning to their capture sites and resuming livestock depredation, with 25% considered partially successful and 25% unknown. In contrast, four of five strategic translocations (80%) clearly met criteria for success: absence of homing, stable range establishment, survival for at least a year, and no livestock depredation. These translocated lions integrated into resident populations and, in two cases, bred successfully, producing at least 35 cubs. Our findings suggest that, under more favorable conditions—including lower livestock densities, higher prey availability, lower resident lion densities, larger area size, and appropriate release strategies—translocation may help mitigate conflict and contribute to lion recovery. We encourage a more nuanced approach toward decision-making around relocating stock-raiding large carnivores, highlighting several key conditions that may improve the practice and policy around this conservation-driven intervention.
Risks of concealing environmental degradation
Hayward, Matt W.; Klop-Toker, Kaya; Momtaz, Salim; Payne, Eliza; Rebec, Louisa; Scanlon, Robert J.; Shuttleworth, Craig M.; Valentine, Nick; Griffin, Andrea S. (Wiley, 2026)
Current practice seeks to conceal the visual impact of land-use change (i.e., development). Six percent of development impact assessments in Australia and 14% of the World Bank's assessments recommend visual impact mitigation. This mitigation results in, for example, vegetated buffer strips alongside cleared agricultural areas and earthen mounds that block environmental degradation from view. These measures make living alongside such development more palatable, but they conceal its negative effects from the general public. The scale of the problem is global with evidence of mandated regulatory drivers for concealment from around the world. These mitigation measures limit the emotional impact of development on people, reducing their likelihood of implementing pro-environmental actions. It is important for the populace to see the scale of human impacts on the environment to increase the likelihood of pro-environmental behaviors and decisions that will help ease the crises facing the environment. We recommend overtly exposing the public to environmental degradation to improve understanding of environmental impacts, increase environmental knowledge, trigger pro-environmental emotions and actions, and help recalibrate people's understanding of biodiversity loss. Policies and research into the effect of creative public imagery designed to improve communication into environmental destruction while minimizing habituation are important, and ensuring that the “greening” of gray infrastructure yields genuine biodiversity benefits is also critical.
Identifying hotspots of faunal data deficiency to direct urgent research and monitoring
Hayward, Matt W.; Verdon-Kidd, Danielle; Colyvas, K.; Saxon, Ellen; Griffin, Andrea S. (Wiley, 2026)
Data deficiency is a substantial challenge for extinction risk assessments because incomplete data means we cannot accurately identify priority protected areas for conservation. Here, we use the International Union for Conservation of Nature (IUCN) distributions of amphibians, sharks and rays, fish, mammals, birds, and reptiles to identify hotspots of data deficient species. We found that areas with high numbers of data deficient species were not randomly distributed and did not necessarily overlap with hotspots of biodiversity, particularly in the Amazon and West Africa. Data deficiency hotspots were concentrated around tropical South America, Africa, and Southeast Asia; however, this distribution varied between taxa. Hotspots of data deficient amphibians were concentrated around the tropical Andean forests of Colombia, Peru, and Ecuador; throughout Brazil; and in the New Guinea Highlands. The tropical forests of the Congo River basin, Papua New Guinea, and the Philippines were hotspots for avian data deficiency. Data deficient chondrichthyans were concentrated in the tropical seas, particularly around the western coast of Africa, East Asia, and the tropical Americas. Indochina was identified as the primary hotspot for data deficient freshwater fish, whereas the Indo-Pacific was the primary hotspot for data deficient marine fish. Data deficient marine mammals were broadly distributed around the southern oceans, South America, Southeast Asia, and Northwest Africa. Data deficient herpetofauna were concentrated around tropical Asia, whereas tropical South America, Indonesia, and central Africa were the hotspots for data deficient terrestrial mammals. Although data deficiency reflected drivers of biodiversity more broadly (e.g., latitude), other factors were also influential, including the amount of conservation funding invested by a country and population density. Increasing evidence suggests that data deficient species are disproportionately likely to be threatened with extinction. Scientists urgently need to focus their research efforts on these data deficiency hotspots and ensure protected area networks are suitably representative and include data deficient species. Furthermore, the accuracy of status assessments needs to be ascertained, and data deficient species need to be prioritized for study to ensure they are not lost before they are identified.
Trophic overlap between three semi-aquatic carnivores in the Highveld Grassland, South Africa
Somers, Michael J.; Grünschloss, Sonica; Scott, Elréze; Ganswindt, Andre; Ramahlo, Mmatsawela (IUCN Otter Specialist Group, 2026-04)
Semi-aquatic carnivores often coexist in riparian habitats despite overlapping prey preferences. We determined the diets of African clawless otters (Aonyx capensis), spotted-necked otters (Hydrictis maculicollis), and water mongooses (Atilax paludinosus) coexisting in the Bankenveld ecotone, South Africa, using scat analysis collected over a two-year period. All three species relied heavily on freshwater crabs (Potamonautes mariepskoppie), which were the most frequent and dominant prey across diets, resulting in high trophic overlap. Otters consumed predominantly aquatic prey, whereas water mongooses exhibited broader diets that included substantial terrestrial components. Crab size selection did not differ among species, indicating extensive overlap in the size spectrum exploited by each species. Seasonal summaries indicated greater winter fish use by African clawless otters, while water mongooses showed broader winter diets that included more mammals alongside continued use of insects. Despite high dietary overlap, differences in dietary breadth and seasonal flexibility likely facilitate coexistence. This study provides the first dietary assessment of these carnivores in a Highveld grassland river system. Maintaining healthy riparian prey communities, especially freshwater crabs and fish, is crucial for sustaining these carnivore groups.
Individual specialization and temporal changes in Antarctic fur seal trophic ecology from a multi-tracer approach
Friscourt, Noemie; Walters, Andrea; Wotherspoon, Simon; Wege, Mia; Chapman, Christopher C.; Brewer, Elizabeth A.; De Bruyn, P.J. Nico; Oosthuizen, W. Chris; Cherel, Yves; Arthur, Benjamin; Lea, Mary-Anne (Wiley, 2026-06)
Substantial individual variation in diet and foraging strategies can exist within populations. These differences can enhance individual foraging efficiency, reduce intraspecific competition, and provide fitness advantages that increase the resilience of a population. Understanding the extent and stability of individual variation, and its contribution to population niche dynamics, is therefore important for interpreting ecological responses, particularly under changing environmental conditions. We used bulk and compound-specific stable isotope analyses together with tracking data to assess individual- and population-level variation in the foraging strategies of adult female Antarctic fur seals (Arctocephalus gazella) from Marion Island (southern Indian Ocean), during the winter migration period, over a decade (2008–2018). We aimed to (1) determine the existence and degree of individual specialization within the population, (2) identify foraging strategies and assess potential influences of body size, and (3) evaluate the temporal stability of foraging strategies, trophic position, and the population isotopic niche, considering potential changes in isotopic baselines. Isotopic data from 129 whiskers from 80 individuals revealed four main foraging strategies, with individuals ranging from extreme specialists to generalists. Corresponding tracking data highlighted differences in the use of oceanographic features niches among these groups, notably in the time spent south or north of the Polar Front. Observed foraging patterns were not explained by body size but instead likely reflect a combination of intrinsic (e.g., energetic costs, experience, genetic legacy) and extrinsic factors (e.g., intra- and interspecific competition and environmental variability). Interannual fluctuations in the population's isotopic niche were also detected, potentially linked to changes in environmental conditions, highlighting the population's adaptability to ecosystem changes. Foraging strategies appear to be temporally stable, as 61% of the 31 females sampled over multiple years showed fidelity to foraging areas, and 74% in their resource use. This suggests that while the population exhibits adaptability to environmental variability, individual seals may consistently employ specific foraging behaviors to limit the potential costs of shifting foraging area and diet. Given the accelerating impacts of climate change on the Southern Ocean, this study underscores the value of stable isotope analysis of whiskers as a powerful, minimally invasive tool for long-term ecological monitoring.
Habitat utilization preference by small mammals is associated with geomorphic and soil properties : a case study of the plateau pika from the Eastern Qinghai-Tibet Plateau
Qin, Faming; Chen, Yingyuan; Tang, Zhongmin; Oosthuizen, Maria Kathleen; An, Shenghui; Wei, Wanrong (Wiley, 2026-06)
Amid accelerating climate change, understanding how wildlife adjusts to environmental constraints, particularly via habitat use, is essential. In high-altitude regions with extreme environmental conditions and strong ecological filtering effects, geomorphic and soil characteristics are critical factors influencing habitat utilization preferences. Previous studies of factors affecting wildlife habitat-use preferences have primarily focused on low-altitude areas. However, research remains scarce on the relationship between habitat utilization preferences of small mammals in plateau regions and geomorphic and soil characteristics. In this study, we selected 66 plots from 19 typical distribution areas of pikas in three counties of the Qinghai-Tibetan Plateau to assess the relationship between the pika's habitat-utilization preferences and geomorphic and soil characteristics at a large scale. The results revealed that the factors affecting the habitat use of pikas are potentially similar across regions. The resource selection index (Ei) showed a clear preference for specific geomorphic and soil characteristics. In addition, we found a significant correlation between PC1–PC4 and pika density, and both principal component analysis (PCA) and generalized additive models (GAM) indicated that all geomorphic and soil properties, except soil depth, affect the habitat use of pikas. Overall, pikas preferred flat terrain with a wide field of view (“beach”) and sunny, south-facing slopes; including running water sources, with the distance between the preferred habitats to water resources related to the type of water resources. In addition, pikas preferred loam (Ei = 0.258), soil depths > 40 cm (Ei = 0.214) but < 60 cm (Ei = 0.241), soil organic matter between 5% and 15% (Ei = 0.359) and soil moisture between 10% and 20% (Ei = 0.290). Our results highlight that the habitat-utilization preferences of pikas are highly dependent on geomorphic and soil characteristics. Future analyses of factors affecting habitat utilization preferences for small mammals should take geomorphic and soil characteristics into consideration.
Fence removal enhances elephant movement and promotes behavioural, physiological and ecological functioning
Friswold, Brooke; Van de Water, Antoinette; Mitchell, Brett; House, Sally; Mitchell, Jaco; Aiyanna, Harin; Delsink, Audrey K.; Garai, Marion; Ganswindt, Andre; Gale, George (Wiley, 2026-05)
Fenced reserves are widely used to conserve and manage African savanna elephants (Loxodonta africana) in South Africa. However, the effects of fencing and fence removal on elephant wellbeing, movement and ecosystem dynamics remain limited in understanding, with few studies incorporating these elements. We hypothesised that fence removal would increase elephant movement flexibility and range, reduce behavioural disturbance and increase sociality, reduce stress-related biomarkers and redistribute browsing pressure. We evaluated how a resident elephant population in a private reserve in the Eastern Cape, South Africa, responded to the removal of two internal fences by integrating focal behavioural observations, faecal glucocorticoid metabolite (fGCM) analyses, NDVI-based vegetation assessments and GPS collar data collected before and after fence removal. Fence removal increased home-range extent, seasonal mobility and inter-herd spatial overlap, with elephants incorporating newly accessible habitat at variable rates. Initial movement was towards lower density environments during the exploratory phase, with greater distribution in space utilisation over time. Behavioural responses indicated short-term increases in aggression, vigilance and disturbance-related behaviours immediately after fence removal, followed by stabilisation, reduced aggression and increased affiliative behaviour over time. Activity budgets shifted towards increased locomotion and reduced foraging, consistent with exploratory behaviour. fGCM concentrations declined significantly following fence removal and remained significant after accounting for demographic and environmental variables, suggesting reduced physiological stress. Vegetation dynamics were spatially heterogeneous yet comparable between areas of elephant presence and absence. This suggests that expanded access redistributed browsing pressure without causing disproportionate vegetation loss with vegetation change primarily driven by environmental variability and not elephant access. These findings suggest that fence removal can promote more natural movement, behavioural responses and physiological regulation, while maintaining vegetation dynamics consistent with background climatic variability. Fence removal may therefore provide an alternative or complementary approach to population management by alleviating spatial constraints and redistributing ecological pressure across the landscape.
Dynamic migratory strategies and foraging habitats of southern right whales revealed by satellite telemetry
Germishuizen, Matthew; Zerbini, Alexandre N.; Kennedy, Amy; Vichi, Marcello; Wilkinson, Christopher; Vermeulen, Els (Wiley, 2026-07)
Understanding the migratory and foraging behaviour of wide-ranging marine predators is crucial for effective conservation planning, particularly in capital breeders where foraging success directly influences reproductive success and population dynamics. For South Africa's southern right whale (SRWs), reproductive success has declined over recent decades, yet contemporary offshore migratory routes and foraging habitats remain poorly known. Here, satellite-linked tags deployed on 34 adult SRWs between 2021 and 2024 were used to investigate migratory strategies and identify environmental correlates of offshore area-restricted search (ARS) behaviour. ARS locations derived from a movement-persistence model were linked to environmental covariates using a random-forest habitat model to identify predictors of foraging behaviour, map suitable offshore foraging habitat, and predict habitat suitability across the wider Southern Ocean foraging range of the South African population. Whales ranged widely across the South Atlantic and southwest Indian Oceans, concentrating foraging effort within the Antarctic Circumpolar Current (ACC), the high-latitude seasonal ice zone, around the Crozet Islands, and within the Benguela upwelling system. Seven individuals (21%) undertook trans-Atlantic migrations to foraging grounds shared with the SRW population of the Southwest Atlantic, demonstrating basin-scale connectivity between populations. Random forest analyses identified environmental covariates associated with ARS behaviour across multiple oceanographic regions with high predictive performance (AUC = 0.90). Predicted habitat suitability highlighted suitable offshore foraging habitat associated with frontal systems, shelf-associated habitats, upwelling regions, and high-latitude seasonal ice habitats across the Southern Ocean. These findings provide the first environmentally explicit habitat-modelling assessment of contemporary offshore foraging habitat for the South African SRW population. Results show this population exhibits diverse migratory routes and foraging behaviours, relying on a wide range of oceanographic habitats that may facilitate behavioural responses and plasticity to variability in foraging conditions across the Southern Ocean.
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 Harvey; 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.

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