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Environmental contaminants endanger human health and non-target organisms such as crocodiles (Crocodylus acutus) that live in aquatic bodies surrounding agricultural areas. Due to their intrinsic characteristics, these organisms could be bioaccumulating and transmitting organochlorine pesticides (OCs) to their eggs. The objectives of this study were to determine the OCs in infertile eggs of C. acutus from Sinaloa and their correlation with the morphometric characteristics (MC), and to perform a preliminary estimate of the ecological risk due to the presence of pesticides using the PERPEST model. In June 2022, 76 infertile eggs (Ie) were collected: 57 from wild areas (Wa) and 19 from a crocodile farm (CSMf). Determination of OC in Ie was performed according to the USEPA method 8081b, modified. The observed percentages of Ie in Wa were 31.48% and 21.33% in CSMf. Twenty OCs were detected in the Ie, where dieldrin recorded the highest average concentration in Wa (6542.6 ng/g), and endosulfan-II in the CSMf (2172.8 ng/g). Bad negative and positive correlations were observed between OCs and MC, standing out the correlations between endosulfan-II and %Ie (-0.688) in the Wa, Cedritos drain, and between endrin and the weight of Ie (0.786) of the CSMf. The evaluation of the ecological risks of the aquatic environment due to the presence of OCs follow the sequence cyclodienes > aromatic > alicyclic hydrocarbons. A potential risk to the endocrine health of the species C. acutus was observed. Crocodiles are excellent biological models for monitoring the effects of OCs. [ABSTRACT FROM AUTHOR]

Dietary preferences of extant reptiles can be directly observed, whereas diet reconstruction of extinct species typically relies on morphological or dental features. More specific information about the ingested diet is contained in the chemistry of hard tissues. Stable isotopes of calcium and strontium show systematic fractionations between diet and skeletal bioapatite, which is applied for diet and trophic-level reconstructions of extant and extinct vertebrate species. Here, we present the first comprehensive analysis of stable calcium and strontium isotopes of bones and teeth from 28 extant reptiles, including lepidosaurs and archosaurs (crocodilians) with distinct herbivorous to faunivorous feeding behaviour, establishing a dietary reference frame. Both calcium and strontium isotopes exhibit systematic offsets between dietary groups, with insectivores having the highest, herbivores intermediate and carnivores the lowest calcium and strontium isotope values. Although the isotopic trophic-level effect is similar to mammals, the absolute calcium isotope values in reptiles are more positive in each diet category. Combining isotopic data with dental microwear texture analysis enables a refined understanding of reptile feeding ecology and the identification of durophagous diets. This toolbox opens new possibilities for improved dietary reconstructions of extinct taxa, such as dinosaurs and other non-mammalian species in the fossil record. [ABSTRACT FROM AUTHOR]

Crocodilians are susceptible to a range of virus infection including influenza A virus (IAV). However, little is known about the ecology and epidemiology of IAV in crocodile species. This study aimed to investigate IAV infection in farmed Siamese crocodiles in central Thailand. We collected plasma samples and pharyngeal swab samples from Siamese crocodiles residing in 13 crocodile farms in 9 provinces of central Thailand during 2019. Additional archival plasma samples of Siamese crocodiles collected in 2012 and 2018 were also included in the study. Plasma samples were screened for influenza A antibodies by a hemagglutination inhibition (HI) assay and positive were evaluated by a cytopathic effect/hemagglutination based-microneutralization (MN) assay. Swab samples were tested for influenza viral RNA by a real-time RT-PCR assay targeting the influenza matrix (M) gene. Among 246 tested plasma samples, the overall seroprevalence of antibodies against IAV in farmed Siamese crocodiles was 17.5% (43/246). The most common hemagglutinin (HA) subtype was H2 (46.5%, 20/43) followed by H9 (39.5%, 17/43), human H1 (14%, 6/43) and H1 (7%, 3/43). Multiple HA subtypes were also detected in 7% (3/43) of infected crocodiles with combination of H1 and H2 subtypes. All 126 tested swab samples were negative for influenza viral RNA. In addition, we demonstrated the ability of wild-type IAV subtypes (H1, H2, H9 and human H1) to infect primary Siamese crocodile fibroblast cells. To our knowledge, this is the first report of serological evidences of avian and human IAV infection in Siamese crocodiles. Our findings highlighted the role of crocodile species in the ecology of IAV particularly the potential to serve as the reservoir or mixing vessel for the viruses that significantly threaten both human and animal health. [ABSTRACT FROM AUTHOR]

Concerns in crocodiles sustainability have long been overlooked, due to humans fear of its ferocity and unresolved human-crocodile conflicts. The siamese crocodile (Crocodylus siamensis) and false gharial (Tomistoma schlegelii) are considered threatened by the IUCN red list because of their limited range and declining populations. In this study we developed habitat suitability model for both species and overlaid with anthropogenic factors to mitigate conflict between crocodiles and human in Mesangat-Suwi Wetland, East Kalimantan, Indonesia. We collected species presence from 2018-2023, measured environmental variables, interviewed 100 respondents, and mapped all information with Maximum Enthropy program (MaxEnt). Results showed that different factors influenced the habitat distribution for each species. Specifically, distance from swamps was affected the most for both crocodiles. Our model found that the potential habitat was much smaller than the non-potential ones due to humans' intrusion. Much of the Mesangat-Suwi area was covered in high-conflict zones between humans and crocodiles, endangering both species even more. Hence, serious actions were urgently needed to resolve the conflict, either by prevention and mitigation actions, to ensure human-crocodile coexistence in East Kalimantan. [ABSTRACT FROM AUTHOR]

The American crocodile (Crocodylus acutus) is a federally and state‐protected species classified as threatened by the United States Fish and Wildlife Service and the State of Florida; however, its population has increased since gaining legal protection in 1967. Concurrently, the number of reported human–crocodile conflicts has also increased, analogous to known conflicts surrounding other large (typically terrestrial) predators recovering from historical population declines. Although biology and ecology are the foundation of effective wildlife management strategies, human dimensions need to be considered to develop realistic and attainable conservation objectives. To better understand how South Florida residents perceive American crocodiles and their management, we used a mixed‐mode internet and mail survey. We obtained survey data from 28 May 2021 to 20 September 2021 from people living within the range of the American crocodile in Florida. There was little variation in opinions of 6 management actions presented for consideration under each of 3 different human–crocodile interaction scenarios. The strongest consensus was around euthanizing a crocodile (highly unacceptable under all 3 scenarios) with the management action of leaving the crocodile alone and monitoring the situation showing the least amount of consensus and shifting from slightly acceptable to slightly unacceptable the closer a hypothetical crocodile was in proximity to a resident's private property. Regression modeling showed respondents who were older, female, and those with children at home were less likely to prefer an increase in the crocodile population. Respondents who perceived more benefits from crocodiles and less risk from them tended to be relatively knowledgeable about crocodiles, had higher trust in the Florida Fish and Wildlife Conservation Commission (FWC), and were more likely to prefer a larger crocodile population. Further, spatial mapping revealed variation in tolerance for crocodiles and trust in FWC's ability to manage them. We reveal opportunities for targeted education and outreach efforts with the potential to affect tolerance of a large reptilian carnivore in a region experiencing rapid human development. [ABSTRACT FROM AUTHOR]

Nature-inspired bionic algorithms have become one of the most fascinating techniques in computational intelligence research, and have shown great potential in real-world challenging problems for their simplicity and flexibility. This paper proposes a novel nature-inspired algorithm, called the crocodile optimization algorithm (COA), which mimics the hunting strategies of crocodiles. In COA, the hunting behavior of crocodiles includes premeditation and waiting hunting. The premeditation behavior is an important hunting way for crocodiles to hide themselves from their prey and to explore more potential areas, and the waiting hunting behavior is another means by which crocodiles make surprise attacks on their prey that appears in their hunting range. The performance of the proposed COA is validated by comparing it with other competitor algorithms on 29 standard test functions and 5 real-world engineering optimization problems. The experimental results show that the comprehensive performance of COA outperforms both of its similar variants and most of other state-of-the-art algorithms, in terms of solution accuracy, robustness and convergence speed. Statistical tests also validate the potential applications of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) in detecting tuberculous diaphragmatic abscess (TDA) of the right diaphragm and provide a reference for its clinical diagnosis. Methods: A retrospective analysis was conducted on 33 patients with right TDA confirmed via surgery and biopsy. The diagnostic accuracy of CEUS and routine ultrasound for detecting right TDA was compared. Results: Among the 33 right TDA cases, the lesions primarily exhibited mixed and low echogenicity, with an orientation parallel to the diaphragmatic surface. Eighteen patients (54.5%) demonstrated the characteristic "crocodile mouth sign." Heterogeneous enhancement was observed in most cases (24 patients) compared to homogeneous or no enhancement. The diagnostic accuracy of routine ultrasound for right TDA was 54.50% (18/33), whereas CEUS demonstrated a significantly higher accuracy of 78.78% (26/33) (χ2 = 4.364, P = 0.037). Conclusion: CEUS provides valuable insights into the vascular characteristics of right TDA, with most cases showing mixed echogenicity and heterogeneous enhancement. The "crocodile mouth sign" was a distinctive feature, highlighting the utility of CEUS in improving diagnostic accuracy for right TDA. [ABSTRACT FROM AUTHOR]

We describe Baalemys mansillai gen. et sp. nov. a chelid turtle, based on an articulated shell from the Portezuelo Formation of the Baal locality, northern shore of Barreales lake, Neuquén Province, Argentina. Baalemys mansillai gen. et sp. nov. is distinguished from other chelids by its oval shape, moderate size, distinctive granulated ornamentation, narrow nuchal plate, first hexagonal neural with short posterolateral margins, a second neural plate that is a regular hexagon, and a posterior lobe that is longer than both the anterior lobe and the bridge. This unique combination of features supports the establishment of a new genus and species. Baalemys mansillai gen. et sp. nov was discovered in the Baal locality with sauropod dinosaurs, theropod dinosaurs, crocodiles, pelomedusoid turtles and other genera of chelids; a similar biota was identified in other localities of the Portezuelo Formation. The identification of Baalemys mansillai gen. et sp. nov. significantly adds to our knowledge of the diversity of pleurodiran turtles from the Portezuelo Formation, the Neuquén Basin, and the broader Patagonian region. [ABSTRACT FROM AUTHOR]

As big data technology has developed, so have complex applications that require increasing resources. The need for high-performance reading and writing increases the usage of NoSQL (MongoDB) databases. As the number of queries in a given amount of time negatively affects the performance of the database, an automated index selection strategy should be used to improve the database performance. This study proposes an Optimized Deep Deterministic Policy Gradient (ODDPG) to select the optimal index. The Adaptive Crocodile Optimization Algorithm (ACOA) is used to improve DDPG's decision-making performance. The ACOA algorithm is used to receive the best action sequences of a DQN. Simulation results showed that the proposed method achieved better results than the existing DDPG model by 2.3% in Average Time Of Query (ATQ) executed, 10% in Query Per Hour (QPH), and 11% in throughput. [ABSTRACT FROM AUTHOR]

This paper introduces a multi‐degree of freedom bionic crocodile robot designed to tackle the challenge of cleaning pollutants and debris from the surfaces of narrow, shallow rivers. The robot mimics the "death roll" motion of crocodiles which is a technique used for object disintegration. First, the design incorporated a swinging tail mechanism using a multi‐section oscillating guide‐bar mechanism. By analyzing three‐, four‐, and five‐section tail structures, the four‐section tail was identified as the most effective structure, offering optimal strength and swing amplitude. Each section of the tail can reach maximum swing angles of 8.05°, 20.95°, 35.09°, and 43.84°, respectively, under a single motor's drive. Next, the robotic legs were designed with a double parallelogram mechanism, facilitating both crawling and retracting movements. In addition, the mouth employed a double‐rocker mechanism for efficient closure and locking, achieving an average torque of 5.69 N m with a motor torque of 3.92 N m. Moreover, the robotic body was designed with upper and lower segment structures and waterproofing function was also considered. Besides, the kinematic mechanism and mechanical properties of the bionic crocodile structure were analyzed from the perspectives of modeling and field tests. The results demonstrated an exceptional kinematic performance of the bionic crocodile robot, effectively replicating the authentic movement characteristics of a crocodile. [ABSTRACT FROM AUTHOR]

An ectotherm's performance and physiological function are strongly tied to environmental temperature, and many ectotherms thermoregulate behaviourally to reach optimum body temperatures. Tropical ectotherms are already living in environments matching their thermal tolerance range and may be expected to conform to environmental temperatures. We tracked the body temperatures (Tb) of 163 estuarine crocodiles across 13 years and compared Tb of 39 crocodiles to water temperature gathered using fish-borne sensors (Tw) across 3 years (2015–2018). While Tb largely conformed closely to Tw, we found inter- and intra-individual differences in relative body temperature (Tb–Tw) that depended on sex and body size as well as the time of day and year. Deviations from Tw, especially during the warm parts of the year, suggest that thermoregulatory behaviour was taking place: we found patterns of warming and cooling events that seemed to mediate this variation in Tb. Thermoregulatory behaviour was observed most frequently in larger individuals, with warming events common during winter and cooling events common during summer. By observing free-ranging animals across multiple years, we found that estuarine crocodiles show yearly patterns of active cooling and warming behaviours that modify their body temperature, highlighting their resilience in the face of recent climate warming. Our work also provides the first evidence for thermal type in large-bodied reptiles. [ABSTRACT FROM AUTHOR]

Background: Crocodiles are semi-aquatic animals well adapted to hear both on land and under water. Currently, there is limited information on how their amphibious hearing is accomplished. Here, we describe, for the first time, the ear anatomy in the living crocodile using photon-counting detector computed tomography (PCD-CT) and 3D rendering. We speculate on how crocodiles, despite their closed ear canals, can use tympanic hearing in water that also provides directional hearing. Material and Methods: A Cuban crocodile (Crocodylus rhombifer) underwent photon-counting detector computed tomography (PCD-CT), under anesthesia and spontaneous respiration. In addition two seven-month-old C. rhombifer and a juvenile Morelet´s crocodile (Crocodylus moreletii) underwent micro-computed tomography (µCT) and endoscopy. One adult Cuviérs dwarf caiman (Paleosuchus palpebrosus) was micro-dissected and video-recorded. Aeration, earflap, and middle ear morphology were evaluated and compared after 3D modeling. Results and Discussion: PCD-CT and µCT with 3D rendering and segmentation demonstrated the anatomy of the external and middle ears with high resolution in both living and expired crocodiles. Based on the findings and comparative examinations, we suggest that the superior earflap, by modulating the meatal recess together with local bone conduction, may implement tympanic hearing in submerged crocodiles, including directional hearing. [ABSTRACT FROM AUTHOR]

In the current study, a new type of novel lattice structures with the concept of bio-mimicking three different nature-inspired designs from the honeycomb patterns, the overlapping phenomenon of the scales present on fish dermal layers, and scutes pattern observed from the top skin layers present on crocodile species are developed. These lattice structures are designed within a cubic volume of 30 mm. The design of lattice unit cells is made with two different geometrical sizes of 4 and 6 mm with different overlapping areas of 20, 30, 40, and 50% calculated from each cell area. All the unit cells' walls are maintained at 0.4 and 0.6 mm only. The specimens are modeled and manufactured through the VAT photopolymerization process, one of the significant additive manufacturing principles for great dimensional accuracy with negligible defects in 3D printing (3DP). The research approach used to develop lightweight bio-inspired structures has been laid out, starting with observing design that served as inspiration. The cured 3D-printed specimens are examined under quasi-static compressive loading carried out on all specimens as per ASTM 1621 standards to measure the crashworthiness response of designed specimens. The energy ingestion capacity of all the specimens is assessed. A good correlation is observed between the experimental and numerical results for better validation. The best design parameters among all 16 specimens are identified for applying energy absorption applications in the automobile and aviation fields in real-time. [ABSTRACT FROM AUTHOR]

We consider the evasion problem in the formulation by Pontryagin and Mishchenko for linear discrete games depending on a parameter. We obtain sufficient conditions and domains of parameter values that ensure the solvability of the evasion problem. The obtained results are applied to the solution of the evasion problem for the well-known problem in the theory of differential games "Isotropic Rockets"–"Boy and Crocodile" in the discrete version. [ABSTRACT FROM AUTHOR]

This paper evaluates interactions between humans, Wild Boars, and crocodiles in mangrove ecosystems of the villages of Benakanda, Bhateni, and South Jambu in Mahakalapada Block in the Kendrapada District of the Indian state of Odisha, using questionnaire surveys. This is an area where mangrove restoration is currently in progress. Using a targeted sampling procedure, 280 respondents representing 14% of the population participated in the study. The results show that negative perceptions differ throughout villages, with a majority of respondents reporting interaction between humans and animals in Bhateni (91%) and South Jambu (98%). The most frequent animal reported to cause harm to crop and livelihoods is Wild Boar (44%). Communities understand the value of mangrove restoration despite facing obstacles brought on by interactions with wildlife. The vast majority of residents (87%) believe that restoration efforts were necessary, and many had taken part in these by themselves, or in conjunction with other communities. [ABSTRACT FROM AUTHOR]

How animals move and associate with conspecifics is rarely random, with a population's spatial structure forming the foundation on which the social behaviours of individuals form. Studies examining the spatial–social interface typically measure averaged behavioural differences between individuals; however, this neglects the inherent variation present within individuals and how it may impact the spatial–social interface. Here, we investigated differences in among-individual (co)variance in sociability, activity and site fidelity in a population of wild estuarine crocodiles, Crocodylus porosus, across a 10-year period. By monitoring 118 crocodiles using coded acoustic transmitters and an array of fixed underwater receivers, we discovered that not only did individual crocodiles repeatably differ (among-individual variation) in each behaviour measured but also in how consistently they expressed these behaviours through time (within-individual variation). As expected, crocodile activity and sociability formed a behavioural syndrome, with more active individuals being less sociable. Interestingly, we also found that individuals that were either more sociable or displayed greater site fidelity were also more specialized (lower within-individual variation) in these behaviours. Together, our results provide important empirical evidence for the interplay between spatial, temporal and social individual-level behavioural variation and how these contribute to forming behavioural niches. This article is part of the theme issue 'The spatial–social interface: a theoretical and empirical integration'. [ABSTRACT FROM AUTHOR]

Summary: Deliberate and accidental adulteration or substitution of crocodile meat with other meats is possibly seen in meat products, which could be challenging to identify. This research aims to develop a new loop‐mediated isothermal amplification for accurately identifying crocodile meat in raw meat and processed food samples. Conditions for LAMP were initially optimised. The LAMP was proven for its high specificity to only crocodile DNA. The LAMP revealed a detection limit of 1 pg/μL crocodile DNA and 0.01% (w/w) crocodile meat in meat admixtures. From forty‐seven commercial processed meat samples, the LAMP detected crocodile content in ten products with the declaration of crocodile on their labels. Without the requirement of DNA purification, the direct LAMP showed its ability to detect crocodile content in both fresh meat and processed meat samples. This LAMP could become a promising alternative to support the food industry, especially for on‐site services and limited‐resource laboratories. [ABSTRACT FROM AUTHOR]

The birth of a baby or the hatching of an egg are moments when the risk of predation is particularly high. In oviparous species where clutches contain many eggs, one strategy for limiting predation is based on mechanisms that synchronise hatching, which reduces the individual risk of being targeted and may allow hatchlings to emerge under parental protection. These mechanisms involve communication signals between eggs and between eggs and parents. While previous studies in various species have shown the importance of sound and vibration signals in these exchanges, how embryos integrate this information remains poorly understood. Here we show that crocodile embryos respond differently to calls emitted by siblings (hatching calls) and to vibrations mimicking parental intervention (rubbing and scratching the shell) or the presence of a predator, suggesting that these two stimuli carry different information. Through playback experiments, we confirm that hatching calls elicit vocal responses and synchronous hatching in mature embryos, while embryos hatch earlier when they perceive vibrations. Our study underlines that the control of hatching by external factors can rely on differential apprehension of multiple sensory inputs by embryos. [ABSTRACT FROM AUTHOR]

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The text from the Oryx journal highlights various conservation efforts and discoveries related to plant and animal species worldwide. It includes findings such as the rediscovery of rare trees in Tanzania, the discovery of a new kind of wood with potential for carbon sequestration, and the successful breeding of Critically Endangered species like the Tahina spectabilis palm and the Siamese crocodile. Conservation initiatives, such as the protection of mangroves in Brazil and the use of innovative methods like frog saunas to combat disease, are also discussed. Additionally, the text addresses the challenges faced by wildlife, such as the impact of the H5N1 bird flu outbreak and the threat to species like the Bornean elephant and the painted woolly bat due to illegal trade and habitat loss. [Extracted from the article]

Simple Summary: Crocodiles are one of nature's most successful predators. Their prey varies according to their size. Adults are known to consume different types of vertebrates; juveniles have a similar diet, although their prey is smaller. However, hatchlings have a diet based mainly on insects. This study aimed to know the diet of hatchling Morelet's crocodiles (Crocodylus moreletii) at a growth stage corresponding to their transition to the juvenile stage. Therefore, it is important to know which vertebrate prey are beginning to appear during this developmental change in crocodiles. To find out, we captured and washed the stomachs of 31 hatchling crocodiles in the Laguna de las Ilusiones in Tabasco, Mexico. Our results showed that crocodiles have a generalist diet, with prey ranging from invertebrates (mainly coleoptera and hemipterans) to some vertebrates (mostly fish and birds). It is important to know these changes in the diet of crocodilians as they develop to help us better interpret their natural history and propose better strategies for their study. The relationship between diet and behavior is essential to understanding an animal's strategies to obtain food, considering ontogenical changes. In reptiles, there is a relationship between the length of the individual and the size of the prey it consumes. Studies have focused on the ontogenetic changes in reptile diets from hatchling to adult, but only a few studies have focused on the transition from hatchling to juvenile. We aimed to describe and analyze the composition, variation, diversity, and overlap in the diet of hatchling Morelet's crocodiles (Crocodylus moreletii) for three size intervals during the hatchling–juvenile transition. We captured 31 hatchling Morelet's crocodiles in an urbanized lagoon in Tabasco. We performed stomach-flushing to determine the diet. Additionally, we estimated the volume, frequency of occurrence, and relative importance of diet items and analyzed the relationship between prey type and the total length of the individuals. The diversity of the hatchling prey suggests a generalist diet. We observed two items not previously described in the diet of hatchling crocodiles. In addition, we found differences in diet between the initial and final size intervals, as increases in the length of prey appeared that they did not consume when they were hatchlings. Our results contribute new information to the dietary changes that occur during the hatchling–juvenile transition. [ABSTRACT FROM AUTHOR]

Apex predators play critical ecological roles, making their conservation a high priority. In tropical Australia, some populations of freshwater crocodiles (Crocodylus johnstoni) have plummeted by greater than 70% due to lethal ingestion of toxic invasive cane toads (Rhinella marina). Laboratory-based research has identified conditioned taste aversion (CTA) as a way to discourage consumption of toads. To translate those ideas into landscape-scale management, we deployed 2395 baits (toad carcasses with toxin removed and containing a nausea-inducing chemical) across four gorge systems in north-western Australia and monitored bait uptake with remote cameras. Crocodile abundance was quantified with surveys. Free-ranging crocodiles rapidly learned to avoid toad baits but continued to consume control (chicken) baits. Toad invasion at our sites was followed by high rates of crocodile mortality (especially for small individuals) at a control site but not at nearby treatment sites. In areas with high connectivity to other waterbodies, repeated baiting over successive years had continuing positive impacts on crocodile survival. In summary, we succeeded in buffering the often-catastrophic impact of invasive cane toads on apex predators. [ABSTRACT FROM AUTHOR]

Araripesuchus is a genus of medium-sized (approximately 1 m long) terrestrial uruguaysuchid crocodyliforms that lived during the Cretaceous in Gondwana. There is limited information about juvenile notosuchian specimens due to the scarcity of well-preserved fossils from ontogenetic series. This study presents a comprehensive morphological description of three juvenile specimens of Araripesuchus (MPCA PV 259, 624, and 1193) from the La Buitrera Paleontological Area, Patagonia, Argentina. These early developmental-stage specimens were identified at a generic level due to the absence of mature anatomical characters for precise classification. Variations were observed between these juveniles and the previously examined adult specimens from the same region. As a result, a list of characters indicating ontogenetic variants was provided. These characters represent discrete traits that vary throughout the life of the individuals and could serve as ontogenetic indicators. This study offers a deeper understanding of the skeletal anatomy of Araripesuchus and its range of morphological variation, providing new data for the characterisation of the genus and potential new taxa of uruguaysuchids. [ABSTRACT FROM AUTHOR]

The mangrove forest in Palawan has the most extensive distribution in the Philippines. The fisher community's perception of the mangrove forest as a known habitat for saltwater crocodiles (Crocodylus porosus) and its fishery benefits in Bugsuk Island were gathered using a participatory systems mental modeling framework for the coastal social-ecological system. From the causal loop diagram, six reinforcing and one balancing feedback loop were derived. The respondents observed a positive growth in the interaction between mangroves and crocodiles in Bugsuk Island, with both populations expanding and providing support to fishery resources. Bugsuk Island represents a unique diversity with great potential for resource conservation and economic benefit. [ABSTRACT FROM AUTHOR]

Human-wildlife conflict is among the major constraint for wildlife management. It often can result in biodiversity decline and jeopardize the delicate balance of ecosystems. The human-saltwater crocodile conflict (hereafter referred to as HCC) is a major wildlife management issue in the Andaman and Nicobar Islands (ANI). Analyzing the long-term trends is vital for better understanding and management of HCC. We used diverse approaches like interviews with local community and victims, HCC register maintained by the Department of Environment and Forest (DoEF), and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to understand the patterns in the reported HCC events in ANI. During the past four decades (1983–2023), 36 fatal and non-fatal HCC were documented in the Andaman Islands. The HCC in ANI exhibited 75% increase after the catastrophic 2004 Indian Ocean tsunami. A comparison of gender involved in HCC indicates that men are often (56%) become victim of HCC owing to their frequent involvement in outdoor activities like fishing, swimming, farming, cattle rearing, etc. The highest number (79%) of HCC and crocodile sightings were documented during the wet season (June-December). The majority of HCC (53%) were reported in the creeks. South Andaman accounts for the highest number of HCC (53%) compared to the rest of the Andaman Islands. High relative frequency of sightings of saltwater crocodile in the creeks of South Andaman like Manglutan nallah (21.47), Dhanikhari nallah (16.56), Collinpur nallah (14.72), and Guptapara nallah (11.04) were recorded between 2016 to 2023. The current scenario demands an urgent need for more fundamental research focusing on the changes in Saltwater crocodile habitats post 2004 tsunami, factors driving the HCC, and development and implementation of an updated management plan to ensure the co-existence of humans and crocodiles in the ANI. [ABSTRACT FROM AUTHOR]

A pervasive maxim in herpetology is that alligators (Alligatoridae) are poor salinity regulators relative to their taxonomic kin, crocodiles (Crocodylidae), evidenced by the purported lack of osmoregulatory abilities of modern Alligator and caimans, which has led to the assumption that freshwater obligation is synapomorphic across the clade, to include extinct members of Alligatoridae, or even Alligatoroidea. Presented here is a brief review of osmoregulation and the fossil record of alligatoroids and a suggestion that salt-tolerance may have been more widespread in the group than is widely assumed, based upon the observations that 1) modern alligatorids are increasingly reported from brackish and marine environs and possess osmoregulatory abilities attained through different regulatory pathways than their crocodile counterparts, and 2) fossil members of the group are routinely (or exclusively) found in or near marine depositional settings, suggesting plausibility that earlier members of the clade were more ocean-going than their extant descendants. Starting with fewer assumptions about the osmoregulatory abilities of extinct taxa may help solve continuing problems in eusuchian biogeography, namely, the dispersals of alligatoroids into Europe and Asia, and multiple dispersal events to and from pre-Interchange South America. Secondary loss of salinity tolerance in Alligator may be adaptive in continental habitats. [ABSTRACT FROM AUTHOR]

Saltwater crocodiles (Crocodylus porosus) are farmed in Australia primarily for their skins and meat. Commercially, they are raised in group pens as hatchlings and grower crocodiles and then moved to unitised (individual) pens for the final finishing stage when they are several years old. They will exhibit aggressive behaviour towards each other in captivity. Unitised pens can prevent animal injury and teeth marks on the skins but may result in other social restrictions. Research into behavioural housing preferences could assist the industry and inform the process of guideline development for optimal crocodile management and welfare. This study assessed the impacts of two housing systems, unitised or group pens, in 20 commercial finishing crocodiles through measuring behavioural profiles of individuals from video recordings, including housing preference when given a choice. Both pens included water and an abovewater shelf, but the crocodiles in unitised pens could also access underneath the shelf. A threat perception test was applied to assess anxiety when housed individually or in groups. However, it was difficult to apply a standardised stimulus to all animals that reliably elicited a behavioural response. Further work would be needed to validate this test for commercial reptiles as the outcomes were not robust. The behavioural observation results showed clear differences in where the crocodiles spent their time across the day and in their activity levels between the pen types. However, interpretation of this variation was confounded by the physical and social differences between the pen types given the inconsistency in shelf access. Behaviours exhibited also differed given there were social opportunities in the group pens where individuals were observed engaged in both aggressive and non-aggressive contact interactions. In the free choice environment, crocodiles spent similar amounts of time in both unitised and group pens, suggesting there were features of both pen types that were attractive to the animals. However, skins were damaged from teeth marks highlighting the physical and economical risks of group housing. Further work could validate behavioural tests to quantify affective state impacts in different housing environments and whether social interactions do provide benefits for improving crocodile welfare. [ABSTRACT FROM AUTHOR]

Social interactions are inevitable in the lives of most animals, since most essential behaviours require interaction with conspecifics, such as mating and competing for resources. Non-avian reptiles are typically viewed as solitary animals that predominantly use their vision and olfaction to communicate with conspecifics. Nevertheless, in recent years, evidence is mounting that some reptiles can produce sounds and have the potential for acoustic communication. Reptiles that can produce sound have an additional communicative channel (in addition to visual/olfactory channels), which could suggest they have a higher communicative complexity, the evolution of which is assumed to be driven by the need of social interactions. Thus, acoustic reptiles may provide an opportunity to unveil the true social complexity of reptiles that are usually thought of as solitary. This review aims to reveal the hidden social interactions behind the use of sounds in non-avian reptiles. Our review suggests that the potential of vocal and acoustic communication and the complexity of social interactions may be underestimated in non-avian reptiles, and that acoustic reptiles may provide a great opportunity to uncover the coevolution between sociality and communication in non-avian reptiles. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics'. [ABSTRACT FROM AUTHOR]

This study assessed the nature and local people's perceptions of human-crocodile (Crocodylus niloticus) conflicts (HCCs) for the period 2007 to 2016 in Kariba town, northern Zimbabwe. A mixed-method approach was used with 150 local fish folks interviewed between July and October 2017 through face-to-face interviews and secondary data on HCC were retrieved from the wildlife authority's records. In contrast to the general perception from fish folks that there was an increase in HCC, secondary data analysis showed no significant trends of crocodile attacks on people for the period under study. HCC was mainly driven by fishing activities which exposed people to crocodile attacks. The study concludes that despite the recorded non-increasing trend in HCCs, HCC is a major conservation issue in Kariba town given enhanced human–wildlife interactions due to the economic needs for local livelihoods. Community educational programs are recommended as a way to manage HCC and close gaps between the conventional scientific and local knowledge. [ABSTRACT FROM AUTHOR]

Simple Summary: Congenital defects have been described in almost every vertebrate group. In crocodiles, teratology alterations have been described in captive animals (pets, zoos, farms) such as Crocodylus niloticus and Gavialis gangeticus. The present study aimed to characterize congenital malformations of C. acutus from a farm in Lomas de Matunilla, Ballestas, Bolívar, Colombia. The analyzed eggs presented macroscopic malformations, with 42 different types of anomalies observed. Limb and tail malformations (29%) were the most common changes observed. The American crocodile (Crocodylus acutus, Cuvier, 1807) (Class Reptilia, Family Crocodylidae) is a crocodile species inhabiting the Neotropics. Congenital defects have been described in almost every vertebrate group. In crocodiles, teratology alterations have been described in captive animals (pets, zoos, farms) such as Crocodylus niloticus or Gavialis gangeticus. The present study aimed to characterize congenital malformations of C. acutus from a farm in Lomas de Matunilla, Ballestas, Bolívar, Colombia. A total of 550 unhatched eggs were examined after embryo death. A total of 61 embryos presented malformations, with 42 different types of anomalies observed. Limb and tail malformations (29%) were the most common malformations observed. Several malformations, such as cephalothoracopagus, thoracopagus, sternopagus, xiphopagus twins, campylorrachis scoliosa, and acrania, were documented in crocodiles for the first time. Research in teratology enhances our understanding of crocodile biology. It plays a role in their conservation and management, thus helping to ensure the long-term viability of these species in their natural habitats. [ABSTRACT FROM AUTHOR]

Simple Summary: South Sudan's recent recovery from armed conflict presents an opportunity to address critical conservation issues affecting the country's biodiversity. The protection of the vast Sudd wetlands is vital for the conservation of many different species and habitats and to ensure the continuity and improvement of the lives of human communities living in it. Animal–human conflict, particularly from crocodiles, poses a significant threat to the adequate protection of the Sudd wetlands. Crocodile attacks have resulted in mortality rates ranging from 50% to 100%. To mitigate these conflicts, changing human behaviour through environmental education is key. This can also improve attitudes towards biodiversity conservation, aligning future development with conservation needs. We conducted interviews with fishers to understand resident people's perception of crocodiles. Crocodiles are seen as a threat because they restrict movement along water bodies, attack livestock and humans, and damage fishing equipment. Attitudes are complex, nuanced, and sometimes polarised within communities. They are feared and hated but also valued for their meat and skin. Some interviewees believe that consuming crocodile meat can improve longevity, sexual potency, and protect against witchcraft. While there is a consensus on the need to destroy crocodile breeding habitats, there is also support for establishing protected areas in the Sudd wetlands. Crocodile sanctuaries would help reduce illegal hunting and protect the species, especially with the growing human population and economic development after the civil war. The nuanced attitudes revealed in certain questions provide a valuable foundation for raising awareness and designing more targeted promotional campaigns. Conflicts between human populations and Nile crocodiles are widespread with crocodiles posing significant threats to fisherfolk and riverine communities across r-Saharan Africa. Hundreds of deadly attacks take place annually, and mortality rates may range from 50% to 100%. Attitudes and perceptions towards crocodiles were studied using structured questionnaires among fisherfolk along the River Nile and the Sudd wetlands in South Sudan. Local communities used crocodiles for their meat and skin/leather trades. The meat is regarded to enhance longevity, sexual potency, and protection against witchcraft. Crocodiles are perceived as a main threat to lives and livelihoods as they restrict people's freedom of movement along water bodies, attack livestock and humans, and devastate fishing equipment. To assess whether responses were influenced by the intensity of crocodile threats, published data on fatal crocodile attacks on humans and livestock were analysed using Generalised Linear Models (GLMs). This analysis indicated a direct link between the number of crocodile attacks and human attitudes. Crocodiles were generally feared and hated, and there was the agreement of the need to destroy breeding habitats. However, some attitudes were complex and nuanced as highlighted by the agreement of local communities on the need to destroy Nile Crocodile breeding habitats on the one hand and the need to establish crocodile sanctuaries as the the preferred strategy to mitigate risks and conflict on the other hand. There is a need for the creation of a crocodile sanctuary in the Sudd wetlands to minimise the risks of illegal hunting and to buffer the increasing pressure on crocodiles due to human population growth and economic upturn after the civil war. [ABSTRACT FROM AUTHOR]

Objectives: The new data provide an important genomic resource for the Critically Endangered Cuban crocodile (Crocodylus rhombifer). Cuban crocodiles are restricted to the Zapata Swamp in southern Matanzas Province, Cuba, and readily hybridize with the widespread American crocodile (Crocodylus acutus) in areas of sympatry. The reported de novo assembly will contribute to studies of crocodylian evolutionary history and provide a resource for informing Cuban crocodile conservation. Data description: The final 2.2 Gb draft genome for C. rhombifer consists of 41,387 scaffolds (contigs: N50 = 104.67 Kb; scaffold: N50-518.55 Kb). Benchmarking Universal Single-Copy Orthologs (BUSCO) identified 92.3% of the 3,354 genes in the vertebrata_odb10 database. Approximately 42% of the genome (960Mbp) comprises repeat elements. We predicted 30,138 unique protein-coding sequences (17,737 unique genes) in the genome assembly. Functional annotation found the top Gene Ontology annotations for Biological Processes, Molecular Function, and Cellular Component were regulation, protein, and intracellular, respectively. This assembly will support future macroevolutionary, conservation, and molecular studies of the Cuban crocodile. [ABSTRACT FROM AUTHOR]

The Corubal (Guinea-Bissau) is a wild but underexplored river in West Africa. This study underscores the potential of environmental DNA (eDNA) surveys to fill biodiversity knowledge gaps in the region. We filtered large water volumes at 11 sites along the watershed, amplified multiple molecular markers, and performed high PCR (polymerase chain reaction) replication and in-depth sequencing. We recorded 2589 amplicon sequence variants, with accumulation curves indicating the need for additional sampling to achieve a thorough survey. The taxonomic assignments were constrained by the scarcity of genomic resources. We recorded 125 species of aquatic and terrestrial vertebrates, including 21 new to the country, predominantly fish (61.9%). Surprisingly, crocodiles were not detected, despite their known presence. There were 11 imperiled species, two of which are Critically Endangered (Western chimpanzee and the mussel Pleiodon ovatus). Our findings support the conservation importance of the Corubal, provide a baseline for future monitoring, and highlight the challenges and opportunities of eDNA surveys in remote tropical rivers. [ABSTRACT FROM AUTHOR]

BackgroundCrocodiles are semi-aquatic animals well adapted to hear both on land and under water. Currently, there is limited information on how their amphibious hearing is accomplished. Here, we describe, for the first time, the ear anatomy in the living crocodile using photon-counting detector computed tomography (PCD-CT) and 3D rendering. We speculate on how crocodiles, despite their closed ear canals, can use tympanic hearing in water that also provides directional hearing.Material and MethodsA Cuban crocodile (Crocodylus rhombifer) underwent photon-counting detector computed tomography (PCD-CT), under anesthesia and spontaneous respiration. In addition two seven-month-old C. rhombifer and a juvenile Morelet´s crocodile (Crocodylus moreletii) underwent micro-computed tomography (µCT) and endoscopy. One adult Cuviérs dwarf caiman (Paleosuchus palpebrosus) was micro-dissected and video-recorded. Aeration, earflap, and middle ear morphology were evaluated and compared after 3D modeling.Results and DiscussionPCD-CT and µCT with 3D rendering and segmentation demonstrated the anatomy of the external and middle ears with high resolution in both living and expired crocodiles. Based on the findings and comparative examinations, we suggest that the superior earflap, by modulating the meatal recess together with local bone conduction, may implement tympanic hearing in submerged crocodiles, including directional hearing.

Cover image: A large estuarine crocodile (Crocodylus porosus) approaching a boat. Photo credit: Cameron J. Baker.. [Extracted from the article]