National Zoological Park

Per- and polyfluoroalkyl substances (PFAS) continue to increase in concentration and prevalence in the environment due to the creation of emerging PFAS and the lack of breakdown of legacy compounds. PFAS are known to both bioaccumulate and biomagnify; therefore, species higher on the food chain, such as marine mammals, are highly exposed to these chemicals. Although studies suggest that considerable maternal transfer of persistent organic pollutants occurs via lactation, data are still lacking on the temporal trends associated with PFAS exposure. In this study, we first optimized the extraction for PFAS from 5 and 1mL of goat's milk using a QuEChERS extraction method to account for precious breast milk samples that are often only available in small volumes. We then utilized a set of dolphin breastmilk samples from an individual mother across a 2-year lactation period to evaluate longitudinal trends in PFAS concentrations and profiles. Thirty PFAS were detected using a multidimensional platform combining liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS), and of these, 20 PFAS were detected continuously across the nursing window of 103-706days. Quantitative analysis using LC-IMS-MS specifically showed concentrations of perfluorooctanesulfonic acid (PFOS) alone surpass weekly intake recommendations, allometrically scaled to dolphins, from the European Food Safety Authority and Food Standards Australia New Zealand by more than 25-fold. PFOS, however, decreased slightly over time, possibly due to transfer from feedings. Suspect screening and non-targeted analysis also identified 12 compounds including 2 long-chained perfluorosulfonic acids not traditionally evaluated in targeted analyses, as well as the PFOS precursors, perfluoroethylcyclohexane sulfonate (PFECHS) and 2-(N-ethylperfluorooctanesulfonamido) ethyl phosphate (SAmPAP). This study therefore suggests that breastmilk is a major contributor to early-life PFAS exposure for mammals, particularly to long-chained PFAS.

Understanding animal space use is central to ecology and conservation, and movement-based habitat selection models provide powerful tools for identifying preferred environments. However, in heterogeneous landscapes, movement constraints limit habitat accessibility, decoupling realised space use from underlying preferences and complicating efforts to scale individual-level movement processes to landscape distributions. We present a steady-state distribution (SSD) framework that integrates locally estimated habitat selection and movement into sparse Markovian transition matrices to predict emergent space use. Across simulations and empirical case studies, SSD consistently outperformed occurrence-based models in predicting space use from individual- to population-level scales. Moreover, SSD proved to be more efficient-and sometimes even more accurate-than more assumptive agent-based model simulations (ABMs). Our approach bridges a key gap between mechanistic movement models and spatial prediction, providing a scalable and computationally efficient approach for translating individual movement behaviour into landscape-scale distribution patterns relevant for ecological inference and conservation planning.

Objective: Maximizing preconception health is an important strategy to prevent preeclampsia in pregnancy. Preeclampsia remains a significant cause of maternal and fetal morbidity and mortality. We examined the associations between preconception maternal body weight, body mass index (BMI), and blood pressure with preeclampsia and its related outcomes. Materials and Methods: We performed a retrospective review of 11,214 live births from 6 months preconception during 2009-2018 in the University of Washington medical system. Outcomes were analyzed using chi-square, analysis of variance, and t-tests. Binary logistic regression was performed to examine associations. Results: Of 11,214 births, 1,539 (13.7%) were complicated by preeclampsia. Individuals with preeclampsia weighed more and had higher blood pressure from 6 months preconception to at least 6 months of pregnancy compared with those without preeclampsia (p < 0.001). Persons with prepregnancy systolic blood pressure (SBP) ≥130 mmHg were 3.2 times more likely to develop preeclampsia than those with SBP <130 mmHg (adjusted odds ratio [aOR] = 3.24, 95% confidence interval [CI] = 2.37-4.43). Women with prepregnancy BMI ≥30 kg/m2 were 2.3 times more likely to develop preeclampsia (aOR = 2.31, 95% CI = 1.72-3.10) than those with BMI <30 kg/m2. Mothers with preeclampsia were more likely to deliver preterm (29% vs. 13.8%, p < 0.001) and have neonates with 5-minute Apgar scores <8 (22.1% vs. 12.1%, p = 0.02) and lower preterm birthweights (1,909 g, 95% CI = 1,813-2,004 g vs. 2,057 g, 95% CI = 1,989-2,123 g). Conclusions: Maternal obesity and elevated blood pressure from 6 months preconception to 6 months of pregnancy were associated with preeclampsia, resulting in maternal and fetal complications.

The return of large carnivores to human-dominated landscapes complicates predator–prey dynamics. While predator and anthropogenic effects are well-documented in intact systems, their interplay in fragmented landscapes remains understudied. We examined whether apex predators still regulate prey and mesopredators in the large mammal community of the Golan Heights—a mosaic of nature reserves, farmland and military zones—where wolves (Canis lupus), golden jackals (Canis aureus) and wild boar (Sus scrofa) are culled to mitigate agricultural losses and human-wildlife conflict. Using 60 camera traps and high-resolution culling data, we quantified predator–prey and intraguild relationships, identifying land protection thresholds at which they shifted. We found that endangered mountain gazelles (Gazella gazella) were most active in protected areas (top 50% of sites) with higher wolf activity and consistently avoided jackals. Species-specific culling increased jackal activity but decreased boar activity in nonprotected areas (lower 65% and 62% of sites, respectively), outweighing the suppressive effects of wolves. While jackal culling modestly benefited gazelles in protected areas, the positive association between wolves and gazelles was sevenfold stronger. These findings suggest that apex predators may maintain their ecological roles in fragmented landscapes up to a threshold of human disturbance, beyond which top-down regulation weakens and ecosystem function deteriorates.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-21402-x.

ABSTRACT Animal welfare is a priority for modern zoos, with environmental enrichment playing a key role in promoting natural behaviors. We studied a captive flock of Chilean flamingos (Phoenicopterus chilensis) at the Chilean National Zoo, which was normally fed in a concrete pool. We evaluated the effects of introducing mud-based enrichment to stimulate natural foraging behavior. We also analyzed the flock’s social dynamics, including dominance hierarchies and interaction networks, to assess their influence on resource access. Social network analysis revealed a highly cohesive group with strong clustering, high transitivity, and a semi-linear dominance structure, indicating stable and frequent agonistic interactions. However, neither dominance rank nor sex significantly influenced foraging behavior. The enrichment intervention led to a 12% increase in overall foraging time, a 23% reduction in pool foraging, and a shift toward using the mud puddles. These changes aligned with the species’ natural foraging strategies. Our findings demonstrate that enrichment can promote species-natural behaviors and highlight its importance in improving the welfare of captive flamingos in zoological settings

Abstract Species distributions depend on fine‐scale ecological processes and population growth trajectories and are influenced by climate and weather changes. However, the characterization of inter‐population dynamics underlying the geographic distributions of migratory organisms remains challenging. We adopted a stable isotope approach to investigate the dynamic population geography of a terrestrial migratory bird across multiple generations. We found that the age‐specific geographic source of Mountain Plovers sampled during winter shifted over four years across a latitudinal gradient. Moreover, our results show that differential effects of climate on the probability of occurrence at the wintering ground could be a driver of population turnover in a migratory species adapted to extreme environmental stochasticity (i.e., drought occurrence). We propose a framework for the identification of spatial and temporal climate and weather components and respective effects on population composition and recruitment into migratory wintering populations. Our approach is useful to reveal population compositional shifts through hydrogen stable isotope analysis while accounting for cumulative drought effects.

Leptospirosis (caused by pathogenic bacteria in the genus Leptospira) is prevalent worldwide but more common in tropical and subtropical regions. Transmission can occur following direct exposure to infected urine from reservoir hosts, or a urine-contaminated environment, which then can serve as an infection source for additional rats and other mammals, including humans. The brown rat, Rattus norvegicus, is an important reservoir of Leptospira spp. in urban settings. We investigated the presence of Leptospira spp. among brown rats in Boston, Massachusetts and hypothesized that rat population dynamics in this urban setting influence the transportation, persistence, and diversity of Leptospira spp. We analyzed DNA from 328 rat kidney samples collected from 17 sites in Boston over a seven-year period (2016-2022); 59 rats representing 12 of 17 sites were positive for Leptospira spp. We used 21 neutral microsatellite loci to genotype 311 rats and utilized the resulting data to investigate genetic connectivity among sampling sites. We generated whole genome sequences for 28 Leptospira spp. isolates obtained from frozen and fresh tissue from some of the 59 positive rat kidneys. When isolates were not obtained, we attempted genomic DNA capture and enrichment, which yielded 14 additional Leptospira spp. genomes from rats. We also generated an enriched Leptospira spp. genome from a 2018 human case in Boston. We found evidence of high genetic structure among rat populations that is likely influenced by major roads and/or other dispersal barriers, resulting in distinct rat population groups within the city; at certain sites these groups persisted for multiple years. We identified multiple distinct phylogenetic clades of L. interrogans among rats that were tightly linked to distinct rat populations. This pattern suggests L. interrogans persists in local rat populations and its transportation is influenced by rat population dynamics. Finally, our genomic analyses of the Leptospira spp. detected in the 2018 human leptospirosis case in Boston suggests a link to rats as the source. These findings will be useful for guiding rat control and human leptospirosis mitigation efforts in this and other similar urban settings.

Abstract Conservation easements—voluntary legal agreements in which a landowner forfeits some development rights in exchange for tax incentives—have become a central part of efforts to limit development in the US. Given the importance of biodiversity conservation on private lands and the rapid growth in conservation easements, they are often celebrated as a win‐win scenario. However, there are also increasing questions about the ecological benefits of conservation easements. The kinds of studies necessary to better understand this issue are challenging for several reasons, and there is a special need for more field studies. We draw on a unique cooperative study of bird biodiversity on private lands conducted by Virginia Working Landscapes, a program of the Smithsonian Institution. We compared bird species abundance on private farmland protected by a conservation easement to private farmland not protected by a conservation easement. We estimated a probability of 0.90 that there was a weak positive effect of conservation easements on bird species abundance at the full community level but found no effect on a smaller subset of grassland‐obligate birds. However, this relationship varied highly across bird species, with some individual species showing positive or negative associations with easements. We argue that (a) these results support recent calls to promote or mandate specific conservation practices on eased properties; (b) the limitations of publicly available data present significant challenges to assessing the ecological impacts of conservation easements; and (c) given these limitations, researchers should exercise caution when making generalized claims about the effects of conservation easements on biodiversity.

The spatial distribution of food shapes animal movement patterns, enabling them to optimize search behaviour and establish efficient routes for resource exploitation. Anthropogenic alteration of primate habitats, fragments available resources, and increases dependency on human food. The rhesus macaque (Macaca mulatta) exhibits a broad spectrum of habitat preferences, encompassing both natural and human-altered landscapes. We studied how these preferences influence ranging behaviour in synanthropic macaques. We studied two similar-sized synanthropic rhesus macaque groups in a 16 km2 suburban area in Dehradun, India. We tagged an adult female from each group with a GPS-GSM logger, recording fixes at 15-min intervals during the summer (April–June) and monsoon (July–August) of 2022. We investigated ranging patterns, habitat selection (via integrated step selection analysis, which models animal movement and habitat preference by analysing step choices based on current location and habitat characteristics), site fidelity, and movement strategy (via evaluation of consecutive step lengths) of the macaques during these two seasons based on the logged GPS coordinates during this period. Overall, the home and core ranges were small. The mean total distance covered diurnally was ~5–8 times the mean of the shortest distance between the first and last location diurnally. The macaques showed a strong preference for roadside and human habitation. Both individuals showed high site fidelity. Both individuals used a strategy of short intensive searches followed by long directed movements. The preference for anthropogenic sites and site fidelity along habitat edges shows recurrent movement to human dumpsites and houses, followed by return trips to preferred refuges. The overall movement strategy of these macaques in human-modified landscapes involved travel between clustered foraging and resting sites, reflecting an adaptive response to spatially fragmented resources and highlighting how resource distribution influences search efficiency and route optimization. This movement pattern may reinforce perceptions of heightened agonistic interactions among humans and influence the long-term dynamics of human-macaque coexistence.

Cloning from historically cryopreserved cells offers a potential means to restore lost genetic variation or increase the representation of particular lineages within bottlenecked species, provided such biobanked materials are archived for such genetic rescue applications. One species for which cloning can provide genetic management benefits is Przewalski’s horse, Equus przewalskii. All ~1800 living Przewalski’s horses, distributed across ex situ breeding facilities and in situ reintroduction sites, are descended from one or more of the five founder lineages established by the 12 horses captured from the wild between 1898 and 1947. Since the 1970s, the San Diego Zoo Wildlife Alliance Biodiversity Bank’s Frozen Zoo® (Escondido, CA, USA) has biobanked cells or tissues of 575 individuals spanning many generations. A pedigree analysis of a subset of deceased individuals represented in the San Diego Zoo Wildlife Alliance Biodiversity Bank’s Frozen Zoo® revealed an underrepresented male that lived from 1975 to 1998, Studbook Number 615 (also known as Kuporovitch), who would be of high value for breeding if cloned. Here, we report that two healthy clones were produced from this cell line using cross-species somatic cell nuclear transfer from 2020 to 2023. Their identification as clones was verified by a standard horse-pedigree genotyping panel, and, for one clone, a whole genome sequencing comparison to the original donor was performed. This is the first time that multiple healthy clones surviving the perinatal period have been produced for an endangered species.