It's not easy being green: Comparing typical skin colouration among amphibians with colour abnormalities associated with chromatophore deficits.

Amphibians can obtain their colour from a combination of several different pigment and light reflecting cell types called chromatophores, with defects in one or several of the cells leading to colour abnormalities. There is a need for better recording of colour abnormalities within wild amphibian populations, as this may provide baseline data that can be used to determine changes in environmental conditions and population dynamics, such as inbreeding. In this study, we provide records of several types of chromatophore deficiencies, including those involving iridophores, xanthophores and melanophores, among two Australian tree frog species; the green and golden bell frog, Litoria aurea, and the eastern dwarf tree frog, L. fallax. We explore these colour abnormalities in terms of the chromatophores that have likely been affected and associated with their expression, in combination with typical colour phenotypes, colour variations and colour changes for these species. We intend for our photographs to be used as a visual guide that addresses the need for more accessible information regarding the physical manifestation of different chromatophore defects among amphibians.

Rapid population increase of the threatened Australian amphibian Litoria aurea in response to wetlands constructed as a refuge from chytrid-induced disease and introduced fish.

Amphibians have declined due to multiple impacts including invasive fish and the disease chytridiomycosis caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Wetland restoration can be used to increase amphibian populations. However the design of created wetlands must account for threats such as Bd and introduced fish. There have been no attempts on a landscape level to manage these threats with habitat design. Here we monitored the green and golden bell frog (Litoria aurea) in 2.6 ha of constructed wetlands designed to enhance breeding and increase survival through passive mitigation of Bd and exotic fish. We compared the fecundity, adult population sizes, introduced fish occupancy, Bd prevalence and survival rates of frogs in created wetlands (CW) to three control sites to determine if and why the habitat design was successful. Monitoring involved weekly capture-recapture during the austral spring and summer for three L. aurea breeding seasons. We hypothesised that (1) if the CWs were successful in passively limiting fish colonisation, a larger number of breeding events would be detected compared to control sites which are known to be widely colonised by introduced fish. (2) If the wetlands were successful in passively mitigating Bd, then we would observe an equal or greater survival rate and equal to or lower Bd prevalence compared to control wetlands. We observed a 3.3-fold increase in adult population size in CW from season 1 to 2, and the population increased further in season 3.We found strong support for hypothesis (1) and weak support for (2). Based on these results, we conclude that this design was beneficial shortly after their formation primarily due to fish exclusion, but further study is required to determine if these benefits extend long-term. Future amphibian restoration studies are needed to improve the design of wetlands to enhance suppression of Bd.

Novel habitat causes a shift to diurnal activity in a nocturnal species.

Plastic responses may allow individuals to survive and reproduce in novel environments, and can facilitate the establishment of viable populations. But can novel environments reveal plasticity by causing a shift in a behavior as fundamental and conspicuous as daily activity? We studied daily activity times near the invasion front of the cane toad (Rhinella marina), an invasive species that has colonized much of northern Australia. Cane toads in Australia are nocturnal, probably because diurnal activity would subject them to intolerably hot and dry conditions in the tropical savannah during the dry season. Our study can demonstrate, however, that upon reaching novel environments some toad populations became diurnal. Sandstone gorges offered cane toads novel, deeply shaded habitat. Gorges with an east-west axis (day-long northern shadow), narrow gorges and narrow sections of gorges contained toads that were primarily diurnal, while gorges with a north-south axis, wide gorges and wide sections of gorges contained mainly nocturnal toads. For example, remote camera data (1314 observations of toad activity times over 789 trap days) revealed strictly nocturnal activity at four 'exposed' sites (99% of 144 observations over 179 days), compared to mostly diurnal activity at a 'shaded' site (78% of 254 observations). Visual encounter surveys confirmed that diurnal activity occurred exclusively at shaded sites, while most nocturnal activity occurred at exposed sites. The close proximity of diurnal and nocturnal toads (4-7 km) provided compelling evidence for the abovementioned physical factors as the proximate cause of the behavioral dichotomy, and for a novel (deeply shaded gorges) environment causing the shift to diurnal activity.

Claw morphometrics in monitor lizards: Variable substrate and habitat use correlate to shape diversity within a predator guild.

Numerous studies investigate morphology in the context of habitat, and lizards have received particular attention. Substrate usage is often reflected in the morphology of characters associated with locomotion, and, as a result, claws have become well-studied ecomorphological traits linking the two. The Kimberley predator guild of Western Australia consists of 10 sympatric varanid species. The purpose of this study was to quantify claw size and shape in the guild using geometric morphometrics, and determine whether these features correlated with substrate use and habitat. Each species was assigned a Habitat/substrate group based on the substrate their claws interact with in their respective habitat. Claw morphometrics were derived for both wild caught and preserved specimens from museum collections, using a 2D semilandmark analysis. Claw shape significantly separated based on Habitat/substrate group. Varanus gouldii and Varanus panoptes claws were associated with sprinting and extensive digging. Varanus mertensi claws were for shallow excavation. The remaining species' claws reflected specialization for some form of climbing, and differed based on substrate compliance. Varanus glauerti was best adapted for climbing rough sandstone, whereas Varanus scalaris and Varanus tristis had claws ideal for puncturing wood. Phylogenetic signal also significantly influenced claw shape, with Habitat/substrate group limited to certain clades. Positive size allometry allowed for claws to cope with mass increases, and shape allometry reflected a potential size limit on climbing. Claw morphology may facilitate niche separation within this trophic guild, especially when considered with body size. As these varanids are generalist predators, morphological traits associated with locomotion may be more reliable candidates for detecting niche partitioning than those associated directly with diet.

Chronic effects of an invasive species on an animal community.

Invasive species can trigger trophic cascades in animal communities, but published cases involving their removal of top predators are extremely rare. An exception is the invasive cane toad (Rhinella marina) in Australia, which has caused severe population declines in monitor lizards, triggering trophic cascades that facilitated dramatic and sometimes unexpected increases in several prey of the predators, including smaller lizards, snakes, turtles, crocodiles, and birds. Persistence of isolated populations of these predators with a decades-long sympatry with toads suggests the possibility of recovery, but alternative explanations are possible. Confirming predator recovery requires longer-term study of populations with both baseline and immediate post-invasion densities. Previously, we quantified short-term impacts of invasive cane toads on animal communities over seven years at two sites in tropical Australia. Herein, we test the hypothesis that predators have begun to recover by repeating the study 12 yr after the initial toad invasion. The three predatory lizards that experienced 71-97% declines in the short-term study showed no sign of recovery, and indeed a worse fate: two of the three species were no longer detectable in 630 km of river surveys, suggesting local extirpation. Two mesopredators that had increased markedly in the short term due to these predator losses showed diverse responses in the medium term; a small lizard species increased by ~500%, while populations of a snake species showed little change. Our results indicate a system still in ecological turmoil, having not yet reached a "new equilibrium" more than a decade after the initial invasion; predator losses due to this toxic invasive species, and thus downstream effects, were not transient. Given that cane toads have proven too prolific to eradicate or control, we suggest that recovery of impacted predators must occur unassisted by evolutionary means: dispersal into extinction sites from surviving populations with alleles for toxin resistance or toad avoidance. Evolution and subsequent dispersal may be the only solution for a number of species or communities affected by invasive species for which control is either prohibitively expensive, or not possible.

The remarkable convergence of skull shape in crocodilians and toothed whales.

The striking resemblance of long-snouted aquatic mammals and reptiles has long been considered an example of morphological convergence, yet the true cause of this similarity remains untested. We addressed this deficit through three-dimensional morphometric analysis of the full diversity of crocodilian and toothed whale (Odontoceti) skull shapes. Our focus on biomechanically important aspects of shape allowed us to overcome difficulties involved in comparing mammals and reptiles, which have fundamental differences in the number and position of skull bones. We examined whether diet, habitat and prey size correlated with skull shape using phylogenetically informed statistical procedures. Crocodilians and toothed whales have a similar range of skull shapes, varying from extremely short and broad to extremely elongate. This spectrum of shapes represented more of the total variation in our dataset than between phylogenetic groups. The most elongate species (river dolphins and gharials) are extremely convergent in skull shape, clustering outside of the range of the other taxa. Our results suggest the remarkable convergence between long-snouted river dolphins and gharials is driven by diet rather than physical factors intrinsic to riverine environments. Despite diverging approximately 288 million years ago, crocodilians and odontocetes have evolved a remarkably similar morphological solution to feeding on similar prey.

Invasive toads shift predator-prey densities in animal communities by removing top predators.

Although invasive species can have substantial impacts on animal communities, cases of invasive species facilitating native species by removing their predators have rarely been demonstrated across vertebrate trophic linkages. The predictable spread of the invasive cane toad (Rhinella marina), however, offered a unique opportunity to quantify cascading effects. In northern Australia, three species of predatory monitor lizards suffered severe population declines due to toad-induced lethal toxic ingestion (yellow-spotted monitor (Varanus panoptes), Mertens' water monitor (V. mertensi), Mitchell's water monitor (V. mitchelli). We, thus, predicted subsequent increases in the abundance and recruitment of prey species due to the reduction of those predators. Toad-induced population-level declines in the water monitor species approached 50% over a five-year period spanning the toad invasion, apparently causing fledging success of the Crimson Finch (Neochmia.phaeton) to increase from 55% to 81%. The consensus of our original and published long-term data is that invasive cane toads are causing predators to lose a foothold on top-down regulation of their prey, triggering shifts in the relative densities of predator and prey in the Australian tropical savannah ecosystem.

The Dry Season Shuffle: Gorges Provide Refugia for Animal Communities in Tropical Savannah Ecosystems.

In the wet-dry tropics, animal species face the major challenges of acquiring food, water or shelter during an extended dry season. Although large and conspicuous animals such as ungulates and waterfowl migrate to wetter areas during this time, little is known of how smaller and more cryptic animal species with less mobility meet these challenges. We fenced off the entire entrance of a gorge in the Australian tropical savanna, offering the unique opportunity to determine the composition and seasonal movement patterns of the small vertebrate community. The 1.7 km-long fence was converted to a trapline that was deployed for 18-21 days during the early dry season in each of two years, and paired traps on both sides of the fence allowed us to detect the direction of animal movements. We predicted that semi-aquatic species (e.g., frogs and turtles) would move upstream into the wetter gorge during the dry season, while more terrestrial species (e.g., lizards, snakes, mammals) would not. The trapline captured 1590 individual vertebrates comprising 60 species. There was a significant bias for captures on the outside of the fence compared to the inside for all species combined (outside/inside = 5.2, CI = 3.7-7.2), for all vertebrate classes, and for specific taxonomic groups. The opposite bias (inside/outside = 7.3, N= 25) for turtles during the early wet season suggested return migration heading into the wet season. Our study revealed that the small vertebrate community uses the gorge as a dry season refuge. The generality of this unreplicated finding could be tested by extending this type of survey to tropical savannahs worldwide. A better understanding of how small animals use the landscape is needed to reveal the size of buffer zones around wetlands required to protect both semi-aquatic and terrestrial fauna in gorges in tropical savannah woodland, and thus in ecosystems in general.

The sensitivity of biological finite element models to the resolution of surface geometry: a case study of crocodilian crania.

The reliability of finite element analysis (FEA) in biomechanical investigations depends upon understanding the influence of model assumptions. In producing finite element models, surface mesh resolution is influenced by the resolution of input geometry, and influences the resolution of the ensuing solid mesh used for numerical analysis. Despite a large number of studies incorporating sensitivity studies of the effects of solid mesh resolution there has not yet been any investigation into the effect of surface mesh resolution upon results in a comparative context. Here we use a dataset of crocodile crania to examine the effects of surface resolution on FEA results in a comparative context. Seven high-resolution surface meshes were each down-sampled to varying degrees while keeping the resulting number of solid elements constant. These models were then subjected to bite and shake load cases using finite element analysis. The results show that incremental decreases in surface resolution can result in fluctuations in strain magnitudes, but that it is possible to obtain stable results using lower resolution surface in a comparative FEA study. As surface mesh resolution links input geometry with the resulting solid mesh, the implication of these results is that low resolution input geometry and solid meshes may provide valid results in a comparative context.

The relationship between cranial structure, biomechanical performance and ecological diversity in varanoid lizards.

Skull structure is intimately associated with feeding ability in vertebrates, both in terms of specific performance measures and general ecological characteristics. This study quantitatively assessed variation in the shape of the cranium and mandible in varanoid lizards, and its relationship to structural performance (von Mises strain) and interspecific differences in feeding ecology. Geometric morphometric and linear morphometric analyses were used to evaluate morphological differences, and finite element analysis was used to quantify variation in structural performance (strain during simulated biting, shaking and pulling). This data was then integrated with ecological classes compiled from relevant scientific literature on each species in order to establish structure-function relationships. Finite element modelling results showed that variation in cranial morphology resulted in large differences in the magnitudes and locations of strain in biting, shaking and pulling load cases. Gracile species such as Varanus salvadorii displayed high strain levels during shaking, especially in the areas between the orbits. All models exhibit less strain during pull back loading compared to shake loading, even though a larger force was applied (pull =30N, shake = 20N). Relationships were identified between the morphology, performance, and ecology. Species that did not feed on hard prey clustered in the gracile region of cranial morphospace and exhibited significantly higher levels of strain during biting (P = 0.0106). Species that fed on large prey clustered in the elongate area of mandible morphospace. This relationship differs from those that have been identified in other taxonomic groups such as crocodiles and mammals. This difference may be due to a combination of the open 'space-frame' structure of the varanoid lizard skull, and the 'pull back' behaviour that some species use for processing large prey.

Oldest pathology in a tetrapod bone illuminates the origin of terrestrial vertebrates.

The origin of terrestrial tetrapods was a key event in vertebrate evolution, yet how and when it occurred remains obscure, due to scarce fossil evidence. Here, we show that the study of palaeopathologies, such as broken and healed bones, can help elucidate poorly understood behavioural transitions such as this. Using high-resolution finite element analysis, we demonstrate that the oldest known broken tetrapod bone, a radius of the primitive stem tetrapod Ossinodus pueri from the mid-Viséan (333 million years ago) of Australia, fractured under a high-force, impact-type loading scenario. The nature of the fracture suggests that it most plausibly occurred during a fall on land. Augmenting this are new osteological observations, including a preferred directionality to the trabecular architecture of cancellous bone. Together, these results suggest that Ossinodus, one of the first large (>2m length) tetrapods, spent a significant proportion of its life on land. Our findings have important implications for understanding the temporal, biogeographical and physiological contexts under which terrestriality in vertebrates evolved. They push the date for the origin of terrestrial tetrapods further back into the Carboniferous by at least two million years. Moreover, they raise the possibility that terrestriality in vertebrates first evolved in large tetrapods in Gondwana rather than in small European forms, warranting a re-evaluation of this important evolutionary event.

The production of anatomical teaching resources using three-dimensional (3D) printing technology.

The teaching of anatomy has consistently been the subject of societal controversy, especially in the context of employing cadaveric materials in professional medical and allied health professional training. The reduction in dissection-based teaching in medical and allied health professional training programs has been in part due to the financial considerations involved in maintaining bequest programs, accessing human cadavers and concerns with health and safety considerations for students and staff exposed to formalin-containing embalming fluids. This report details how additive manufacturing or three-dimensional (3D) printing allows the creation of reproductions of prosected human cadaver and other anatomical specimens that obviates many of the above issues. These 3D prints are high resolution, accurate color reproductions of prosections based on data acquired by surface scanning or CT imaging. The application of 3D printing to produce models of negative spaces, contrast CT radiographic data using segmentation software is illustrated. The accuracy of printed specimens is compared with original specimens. This alternative approach to producing anatomically accurate reproductions offers many advantages over plastination as it allows rapid production of multiple copies of any dissected specimen, at any size scale and should be suitable for any teaching facility in any country, thereby avoiding some of the cultural and ethical issues associated with cadaver specimens either in an embalmed or plastinated form.

An interactive three dimensional approach to anatomical description-the jaw musculature of the Australian laughing kookaburra (Dacelo novaeguineae).

The investigation of form-function relationships requires a detailed understanding of anatomical systems. Here we document the 3-dimensional morphology of the cranial musculoskeletal anatomy in the Australian Laughing Kookaburra Dacelo novaeguineae, with a focus upon the geometry and attachments of the jaw muscles in this species. The head of a deceased specimen was CT scanned, and an accurate 3D representation of the skull and jaw muscles was generated through manual segmentation of the CT scan images, and augmented by dissection of the specimen. We identified 14 major jaw muscles: 6 in the temporal group (M. adductor mandibulae and M. pseudotemporalis), 7 in the pterygoid group (M. pterygoideus dorsalis and M. pterygoideus ventralis), and the single jaw abductor M. depressor mandibulae. Previous descriptions of avian jaw musculature are hindered by limited visual representation and inconsistency in the nomenclature. To address these issues, we: (1) present the 3D model produced from the segmentation process as a digital, fully interactive model in the form of an embedded 3D image, which can be viewed from any angle, and within which major components can be set as opaque, transparent, or hidden, allowing the anatomy to be visualised as required to provide a detailed understanding of the jaw anatomy; (2) provide a summary of the nomenclature used throughout the avian jaw muscle literature. The approach presented here provides considerable advantages for the documentation and communication of detailed anatomical structures in a wide range of taxa.

Beware the black box: investigating the sensitivity of FEA simulations to modelling factors in comparative biomechanics.

Finite element analysis (FEA) is a computational technique of growing popularity in the field of comparative biomechanics, and is an easily accessible platform for form-function analyses of biological structures. However, its rapid evolution in recent years from a novel approach to common practice demands some scrutiny in regards to the validity of results and the appropriateness of assumptions inherent in setting up simulations. Both validation and sensitivity analyses remain unexplored in many comparative analyses, and assumptions considered to be 'reasonable' are often assumed to have little influence on the results and their interpretation. HERE WE REPORT AN EXTENSIVE SENSITIVITY ANALYSIS WHERE HIGH RESOLUTION FINITE ELEMENT (FE) MODELS OF MANDIBLES FROM SEVEN SPECIES OF CROCODILE WERE ANALYSED UNDER LOADS TYPICAL FOR COMPARATIVE ANALYSIS: biting, shaking, and twisting. Simulations explored the effect on both the absolute response and the interspecies pattern of results to variations in commonly used input parameters. Our sensitivity analysis focuses on assumptions relating to the selection of material properties (heterogeneous or homogeneous), scaling (standardising volume, surface area, or length), tooth position (front, mid, or back tooth engagement), and linear load case (type of loading for each feeding type). Our findings show that in a comparative context, FE models are far less sensitive to the selection of material property values and scaling to either volume or surface area than they are to those assumptions relating to the functional aspects of the simulation, such as tooth position and linear load case. Results show a complex interaction between simulation assumptions, depending on the combination of assumptions and the overall shape of each specimen. Keeping assumptions consistent between models in an analysis does not ensure that results can be generalised beyond the specific set of assumptions used. Logically, different comparative datasets would also be sensitive to identical simulation assumptions; hence, modelling assumptions should undergo rigorous selection. The accuracy of input data is paramount, and simulations should focus on taking biological context into account. Ideally, validation of simulations should be addressed; however, where validation is impossible or unfeasible, sensitivity analyses should be performed to identify which assumptions have the greatest influence upon the results.

Embedding and publishing interactive, 3-dimensional, scientific figures in Portable Document Format (PDF) files.

With the latest release of the S2PLOT graphics library, embedding interactive, 3-dimensional (3-d) scientific figures in Adobe Portable Document Format (PDF) files is simple, and can be accomplished without commercial software. In this paper, we motivate the need for embedding 3-d figures in scholarly articles. We explain how 3-d figures can be created using the S2PLOT graphics library, exported to Product Representation Compact (PRC) format, and included as fully interactive, 3-d figures in PDF files using the movie15 LaTeX package. We present new examples of 3-d PDF figures, explain how they have been made, validate them, and comment on their advantages over traditional, static 2-dimensional (2-d) figures. With the judicious use of 3-d rather than 2-d figures, scientists can now publish, share and archive more useful, flexible and faithful representations of their study outcomes. The article you are reading does not have embedded 3-d figures. The full paper, with embedded 3-d figures, is recommended and is available as a supplementary download from PLoS ONE (File S2).

Why the long face? The mechanics of mandibular symphysis proportions in crocodiles.

BACKGROUND: Crocodilians exhibit a spectrum of rostral shape from long snouted (longirostrine), through to short snouted (brevirostrine) morphologies. The proportional length of the mandibular symphysis correlates consistently with rostral shape, forming as much as 50% of the mandible's length in longirostrine forms, but 10% in brevirostrine crocodilians. Here we analyse the structural consequences of an elongate mandibular symphysis in relation to feeding behaviours. METHODS/PRINCIPAL FINDINGS: Simple beam and high resolution Finite Element (FE) models of seven species of crocodile were analysed under loads simulating biting, shaking and twisting. Using beam theory, we statistically compared multiple hypotheses of which morphological variables should control the biomechanical response. Brevi- and mesorostrine morphologies were found to consistently outperform longirostrine types when subject to equivalent biting, shaking and twisting loads. The best predictors of performance for biting and twisting loads in FE models were overall length and symphyseal length respectively; for shaking loads symphyseal length and a multivariate measurement of shape (PC1- which is strongly but not exclusively correlated with symphyseal length) were equally good predictors. Linear measurements were better predictors than multivariate measurements of shape in biting and twisting loads. For both biting and shaking loads but not for twisting, simple beam models agree with best performance predictors in FE models. CONCLUSIONS/SIGNIFICANCE: Combining beam and FE modelling allows a priori hypotheses about the importance of morphological traits on biomechanics to be statistically tested. Short mandibular symphyses perform well under loads used for feeding upon large prey, but elongate symphyses incur high strains under equivalent loads, underlining the structural constraints to prey size in the longirostrine morphotype. The biomechanics of the crocodilian mandible are largely consistent with beam theory and can be predicted from simple morphological measurements, suggesting that crocodilians are a useful model for investigating the palaeobiomechanics of other aquatic tetrapods.

The effects of biting and pulling on the forces generated during feeding in the Komodo dragon (Varanus komodoensis).

In addition to biting, it has been speculated that the forces resulting from pulling on food items may also contribute to feeding success in carnivorous vertebrates. We present an in vivo analysis of both bite and pulling forces in Varanus komodoensis, the Komodo dragon, to determine how they contribute to feeding behavior. Observations of cranial modeling and behavior suggest that V. komodoensis feeds using bite force supplemented by pulling in the caudal/ventrocaudal direction. We tested these observations using force gauges/transducers to measure biting and pulling forces. Maximum bite force correlates with both body mass and total body length, likely due to increased muscle mass. Individuals showed consistent behaviors when biting, including the typical medial-caudal head rotation. Pull force correlates best with total body length, longer limbs and larger postcranial motions. None of these forces correlated well with head dimensions. When pulling, V. komodoensis use neck and limb movements that are associated with increased caudal and ventral oriented force. Measured bite force in Varanus komodoensis is similar to several previous estimations based on 3D models, but is low for its body mass relative to other vertebrates. Pull force, especially in the ventrocaudal direction, would allow individuals to hunt and deflesh with high success without the need of strong jaw adductors. In future studies, pull forces need to be considered for a complete understanding of vertebrate carnivore feeding dynamics.

The craniomandibular mechanics of being human.

Diminished bite force has been considered a defining feature of modern Homo sapiens, an interpretation inferred from the application of two-dimensional lever mechanics and the relative gracility of the human masticatory musculature and skull. This conclusion has various implications with regard to the evolution of human feeding behaviour. However, human dental anatomy suggests a capacity to withstand high loads and two-dimensional lever models greatly simplify muscle architecture, yielding less accurate results than three-dimensional modelling using multiple lines of action. Here, to our knowledge, in the most comprehensive three-dimensional finite element analysis performed to date for any taxon, we ask whether the traditional view that the bite of H. sapiens is weak and the skull too gracile to sustain high bite forces is supported. We further introduce a new method for reconstructing incomplete fossil material. Our findings show that the human masticatory apparatus is highly efficient, capable of producing a relatively powerful bite using low muscle forces. Thus, relative to other members of the superfamily Hominoidea, humans can achieve relatively high bite forces, while overall stresses are reduced. Our findings resolve apparently discordant lines of evidence, i.e. the presence of teeth well adapted to sustain high loads within a lightweight cranium and mandible.

A central role for venom in predation by Varanus komodoensis (Komodo Dragon) and the extinct giant Varanus (Megalania) priscus.

The predatory ecology of Varanus komodoensis (Komodo Dragon) has been a subject of long-standing interest and considerable conjecture. Here, we investigate the roles and potential interplay between cranial mechanics, toxic bacteria, and venom. Our analyses point to the presence of a sophisticated combined-arsenal killing apparatus. We find that the lightweight skull is relatively poorly adapted to generate high bite forces but better adapted to resist high pulling loads. We reject the popular notion regarding toxic bacteria utilization. Instead, we demonstrate that the effects of deep wounds inflicted are potentiated through venom with toxic activities including anticoagulation and shock induction. Anatomical comparisons of V. komodoensis with V. (Megalania) priscus fossils suggest that the closely related extinct giant was the largest venomous animal to have ever lived.