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Trace elements in aquatic environments pose a risk to biological communities; this study investigates the total concentrations of arsenic (As), silver (Ag), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), selenium (Se), lead (Pb), and zinc (Zn) within muscle, carapace, liver, and adipose tissues of diamondback terrapins and common snapping turtles in New Jersey. The effects of tissue type, sex, size, and location upon trace element accumulation were studied. The data obtained indicates that within diamondback terrapins and common snapping turtles, trace element accumulations displayed a significant difference among tissue types and sex (p

Substituted phenylamine antioxidants (SPAs) are used in Canadian industrial processes. SPAs, specifically N-phenyl-1-naphthylamine (PNA), have received very little attention despite their current use in Canada and their expected aquatic and environmental releases. There is a research gap regarding the effects of PNA in wildlife; therefore, Chelydra serpentina (common snapping turtle) was studied due to its importance as an environmental indicator species. A chronic experiment was performed using PNA spiked food (0 to 3446 ng/g) to determine its toxicity to juvenile C. serpentina. A significant increase in cyp1a mRNA level was observed in the liver of turtles exposed to 3446 ng/g PNA, suggesting that phase I detoxification is activated in the exposed animals. Additionally, a significant decrease in cyp2b transcript level was observed at the two lowest PNA doses, likely indicating another metabolic alteration for PNA. This study helped determine the molecular effects associated with a PNA exposure in reptiles.

An adult male snapping turtle with marked palpebral edema and multifocal skin ulceration was found alive in a marsh in southern Ontario in summer 2017. The turtle was transported to a rehabilitation facility and died 4 d after arrival. The carcass was submitted to the Canadian Wildlife Health Cooperative for post-mortem examination. Gross lesions included ulcerative conjunctivitis, necrotizing stomatitis, and splenomegaly. Microscopically, this corresponded to multisystemic fibrinonecrotizing vasculitis and severe fibrinous splenic necrosis. Liver tissue tested positive for frog virus 3-like ranavirus and negative for herpesvirus via polymerase chain reaction. The gross and microscopic lesions were consistent with previous reports of ranavirus infection in turtles and were severe enough to have been the cause of death in this case. This is the first report of morbidity and mortality in a common snapping turtle with a ranavirus infection, and the first reported case of ranavirus infection in a reptile in Canada. Ranaviruses are considered to be an emerging infectious disease in chelonians as they are increasing in distribution, prevalence, and host range.

A review of laboratory and field data, together with recent growth experiments, show that Chelydra serpentina, the common snapping turtle, is unable to hypoosmoregulate in salinities more concentrated than their internal osmotic concentration, about one third that of seawater (100% seawater is defined as 35 parts per thousand = 1000 milliosmoles). Circumstantial evidence suggests an understanding of the nascent stages of adaptation of freshwater vertebrates to high salinity habitats should include incidental immune system effects. Recent advances in the study of autoimmunity and ecoimmunology indicate the immune system of vertebrates plays an integrative role in maintaining homeostasis in the face of changing internal and external stimuli and may clarify why a small percentage of snapping turtle hatchlings can grow at relatively high salinities, at least up to 40% seawater.

We conducted population surveys of freshwater turtles in Diaoluoshan National Nature Reserve, Hainan Province, China, from 2012 to 2019, capturing 20 individuals belonging to 4 species, including 2 native species (big-headed turtle [Platysternon megacephalum] and Hainan four-eyed turtle [Sacalia insulensis]) and 2 alien species (red-eared slider [Trachemys scriptia elegans] and common snapping turtle [Chelydra serpentia]). We captured 12 big-headed turtles and estimated their population density (1.6514 individuals/km) and abundance (14 individuals), both of which indicate that Diaoluoshan National Nature Reserve is an important area for turtle conservation, especially for big-headed turtles.

In reptiles, exposure to hypoxia during embryonic development affects several cardiovascular parameters. These modifications may impose different mechanical stress to the arterial system, and we speculated that the arterial wall of major outflow vessels would be modified accordingly. Since non-crocodilian reptiles possess a partially divided ventricle, ensuing similar systemic and pulmonary systolic pressures, we investigated how morphological and mechanical properties of segments from the left aortic arch (LAo) and the proximal and distal segments of the left pulmonary artery (LPAp and LPAd, respectively) change as body mass (Mb) increases. Eggs from common snapping turtles, Chelydra serpentina, were incubated under normoxia (21% O2; N21) or hypoxia (10% O2; H10), hatched and maintained in normoxia thereafter. Turtles (0.11–6.85 kg) were cannulated to measure arterial pressures, and an injection of adrenaline was used to increase pressures. Portions of the LAo, LPAp and LPAd were fixed under physiological hydrostatic pressures for histology and mechanical assessment. Arterial pressures increased with Mb for N21 but not for H10. Although mechanical and functional characteristics from the LPAp and LPAd were similar between N21 and H10, wall thickness from LAo did not change with Mb in the H10 group, thus wall stress increased in larger turtles. This indicates that larger H10 turtles probably experience an elevated probability of arterial wall rupture without concomitant changes in the cardiovascular system to prevent it. Finally, collagen content of the LPAp and LAo was smaller than in LPAd, suggesting a more distensible arterial wall could attenuate higher pressures from larger turtles.

Despite the North American production ban of polychlorinated biphenyls (PCBs), PCBs are ubiquitous in the environment and in wildlife tissues. Chelydra serpentina serpentina (common snapping turtle) have been used as environmental indicators of PCB pollution upwards of 40 years given their high site fidelity and high trophic position. Despite their long use as indicators of PCB contamination, the effects of PCBs in reptiles remain largely unknown. In this study, we performed two experiments to assess i) bioaccumulation and ii) toxicity of PCBs to 1-month-old C. s. serpentina, to aid in interpretation of PCB burdens. Food pellets were spiked at an environmentally relevant concentration (0.45 μg/g) of the PCB mixture Aroclor 1254 to model hepatic bioaccumulation and depuration, through feeding, for 31 days and clean food for 50 days, respectively. No significant differences in PCB concentrations were observed in liver tissue over the course of the experiment, suggesting that juvenile turtles can likely metabolize low environmentally occurring concentrations of PCBs. Additionally, a dose-response experiment, performed to determine hepatic toxicity and bioaccumulation in juvenile C. s. serpentina, showed a 1.8-fold increase in hepatic expression of cyp1a when fed A1254-spiked pellets (12.7 μg/g; range 0–12.7 μg/g). This gene induction correlates with the significant increase of group 3 PCB congeners measured in the turtle liver, which are known to be metabolized by CYP1A. This study indicates that C. s. serpentina may be a good environmental indicator for PCBs, while more research is needed to assess the effects of body burdens in wild C. s. serpentina.

Temperature during embryogenesis determines sex and has been shown to influence other physiological traits in reptiles. The common snapping turtle (Chelydra serpentina) is an ideal model for testing how temperature impacts behavior in species that display temperature-dependent sex determination. Behavioral assays are crucial to understanding how a changing climate may affect whole organism function in the snapping turtle. Currently, there are few behavioral assays for semi-aquatic vertebrates like turtles. In this study, we used digital cameras to record behavior of fed and fasted hatchling turtles from different incubation temperatures in an open field setting for 20 min in 2018 and repeated the experiment in 2019. Open fields were circular tanks filled with water to a depth of 3.5 cm. Each field was split into four quadrants and two zones (inner and outer). The amount of time turtles spent actively moving, total distance travelled, and several other measures were collected and summarized automatically from videos with open source image analysis software (ImageJ). Satiety and incubation temperature had significant effects on total distance moved, time spent moving, and time moving in the outer zone. These findings indicate that temperature during embryogenesis has a long-lasting effect on neural mechanisms underlying exploratory or general locomotor behavior in turtles.

The common snapping turtle (Chelydra serpentina) is a well studied and broadly distributed member of Testudines; however, very little is known concerning developmental anomalies and soft tissue pathologies of turtles and other reptiles. Here, we present an unusual case of unilateral pulmonary aplasia, asymmetrical carapacial kyphosis, and mild scoliosis in a live adult C. serpentina. The detailed three-dimensional (3D) anatomy of the respiratory system in both the pathological and normal adult C. serpentina, and a hatchling are visualized using computed tomography (CT), microCT, and 3D digital anatomical models. In the pathological turtle, the right lung consists of an extrapulmonary bronchus that terminates in a blind stump with no lung present. The left lung is hyperinflated relative to the normal adult, occupying the extra coelomic space facilitated by the unusual mid-carapacial kyphotic bulge. The bronchial tree of the left lung retains the overall bauplan of the normal specimens, with some minor downstream variation in the number of secondary airways. The primary difference between the internal pulmonary structure of the pathological individual and that of a normal adult is a marked increase in the surface area and density of the parenchymal tissue originating from the secondary airways, a 14.3% increase in the surface area to volume ratio. Despite this, the aplasia has not had an impact upon the ability of the turtle to survive; however, it did interfere with aquatic locomotion and buoyancy control under water. This turtle represents a striking example of a non-fatal congenital defect and compensatory visceral hypertrophy.

Our understanding of reptilian cardiovascular development and regulation has increased substantially for two species the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina) during the past two decades. However, what we know about cardiovascular maturation in many other species remains poorly understood or unknown. Embryonic sea turtles have been studied to understand the maturation of metabolic function, but these studies have not addressed the cardiovascular system. Although prior studies have been pivotal in characterizing development, and factors that influence it, the development of cardiovascular function, which supplies metabolic function, is unknown in sea turtles. During our investigation we focused on quantifying how cardiovascular morphological and functional parameters change, to provide basic knowledge of development in the olive ridley sea turtle (Lepidochelys olivacea). Embryonic mass, as well as mass of the heart, lungs, liver, kidney, and brain increased during turtle embryo development. Although heart rate was constant during this developmental period, arterial pressure approximately doubled. Further, while embryonic olive ridley sea turtles lacked cholinergic tone on heart rate, there was a pronounced beta adrenergic tone on heart rate that decreased in strength at 90% of incubation. This beta adrenergic tone may be partially originating from the sympathetic nervous system at 90% of incubation, with the majority originating from circulating catecholamines. Data indicates that olive ridley sea turtles share traits of embryonic functional cardiovascular maturation with the American alligator (Alligator mississippiensis) but not the common snapping turtle (Chelydra serpentina).

Blood flow patterns and heart rate have rarely been investigated in freely swimming turtles and their regulation during swimming is unknown. In this study we investigated the blood flow patterns and heart rate in surfacing and during graded, submerged swimming activity in common snapping turtles. We further investigated the effects of beta-adrenergic and cholinergic receptor blockade on blood flow and heart rate during these activities. Our findings illustrate that surfacing is accompanied by an increase in heart rate that is primarily due to beta adrenergic stimulation. During swimming this mechanism also increases heart rate while vagal withdrawal facilitates a systemic to pulmonary (left to right) shunt. The results indicate there may be important taxonomic effects on the responses of cardiac function to activity in turtle species.

Historically, egg-bound reptile embryos were thought to passively thermoconform to the nest environment. However, recent observations of thermal taxis by embryos of multiple reptile species have led to the widely discussed hypothesis that embryos behaviorally thermoregulate. Because temperature affects development, such thermoregulation could allow embryos to control their fate far more than historically assumed. We assessed the opportunity for embryos to behaviorally thermoregulate in nature by examining thermal gradients within natural nests and eggs of the common snapping turtle (Chelydra serpentina; which displays embryonic thermal taxis) and by simulating thermal gradients within nests across a range of nest depths, egg sizes, and soil types. We observed little spatial thermal variation within nests, and thermal gradients were poorly transferred to eggs. Furthermore, thermal gradients sufficiently large and constant for behavioral thermoregulation were not predicted to occur in our simulations. Gradients of biologically relevant magnitude have limited global occurrence and reverse direction twice daily when they do exist, which is substantially faster than embryos can shift position within the egg. Our results imply that reptile embryos will rarely, if ever, have the opportunity to behaviorally thermoregulate by moving within the egg. We suggest that embryonic thermal taxis instead represents a play behavior, which may be adaptive or selectively neutral, and results from the mechanisms for behavioral thermoregulation in free-living stages coming online prior to hatching.

Turtles face unique conservation challenges in modern modified river systems. Despite their ecological importance, gaps in knowledge still exist that may hinder their conservation. Turtle by-catch data from the US Army Corps of Engineers' Long-Term Resource Monitoring Program were analyzed for 5 turtle species (false map turtle, Graptemys pseudogeographica; red-eared slider, Trachemys scripta; common snapping turtle, Chelydra serpentina; smooth softshell turtle, Apalone mutica; and spiny softshell turtle, Apalone spinifera) to better understand macrohabitat and mesohabitat use. These species demonstrated differences in habitat use between various macrohabitats, substrata, velocity classes, and depth classes. Common snapping turtles and spiny softshell turtles were captured most often in tributaries, whereas red-eared sliders were captured most often in tributaries and closed side channels. Smooth softshell turtles used open side channels and unstructured main-channel borders most often. False map...

Studies of embryonic and hatchling reptiles have revealed marked plasticity in morphology, metabolism, and cardiovascular function following chronic hypoxic incubation. However, the long-term effects of chronic hypoxia have not yet been investigated in these animals. The aim of this study was to determine growth and postprandial O2consumption (V̇o2), heart rate ( fH), and mean arterial pressure ( Pm, in kPa) of common snapping turtles ( Chelydra serpentina) that were incubated as embryos in chronic hypoxia (10% O2, H10) or normoxia (21% O2, N21). We hypothesized that hypoxic development would modify posthatching body mass, metabolic rate, and cardiovascular physiology in juvenile snapping turtles. Yearling H10 turtles were significantly smaller than yearling N21 turtles, both of which were raised posthatching in normoxic, common garden conditions. Measurement of postprandial cardiovascular parameters and O2consumption were conducted in size-matched three-year-old H10 and N21 turtles. Both before and 12 h after feeding, H10 turtles had a significantly lower fHcompared with N21 turtles. In addition, V̇o2was significantly elevated in H10 animals compared with N21 animals 12 h after feeding, and peak postprandial V̇o2occurred earlier in H10 animals. Pmof three-year-old turtles was not affected by feeding or hypoxic embryonic incubation. Our findings demonstrate that physiological impacts of developmental hypoxia on embryonic reptiles continue into juvenile life.

While organisms are typically considered permanent residents of a community, many transient organisms occupy a community for only brief periods. Despite the duration, the effects of a short visit by a top predator may remain long after departure. To test hypotheses on the impacts of a short-term visit by a top predator on pond communities, we used artificial ponds and constructed food web treatments that varied in trophic structure (Control Food Web = no predators present, Bluegill Food Web = only intermediate predators present, and Full Food Web = top and intermediate predators present). The constructed food webs were replicated five times and contained two prey species (frog tadpoles), an intermediate predator (fish), and one top predator (freshwater turtle). The Full Food Web simulated a four-day visit by Chelydra serpentina (Common Snapping Turtle). Predation by Lepomis macrochirus (Bluegill) reduced mean tadpole survival for Hyla chrysoscelis (Cope's Gray Tree Frog) in all food webs, including the Full Food Web with C. serpentina, compared to the Control Food Web. Although C. serpentina had no effects on tadpoles of H. chrysoscelis, the top predator reduced mean survival and increased mean mass of Rana sphenocephala (Southern Leopard Frog) when compared to the Bluegill Food Web. Therefore, our results suggest that brief visits from transient organisms, especially top predators, can alter community structure and initiate cascading effects.

Spiny softshell turtles (Apalone spinifera), common snapping turtles (Chelydra serpentina), and red-eared sliders (Trachemys scripta elegans) were surveyed for leeches at 16 sites across Texas, U.S.A., from March to December of 2017. Five species of leeches were found (3 from 15 A. spinifera sampled, 4 from 9 C. serpentina sampled, and 3 from 55 T. scripta elegans), representing 3 new host records and 1 new locality record. Leech abundance was also compared to water parameters (ammonia, carbon dioxide, chloride, dissolved oxygen, hardness, nitrite, nitrate, pH, salinity, temperature, and turbidity) and qualitative environmental variables (vegetation, sediment, latitude, longitude, season, and water body) through principle components analysis, stepwise regression, and model selection. We found significant effects of sediment composition and seasonality on leech abundance. This study adds novel data on leech–host associations, distributions, and diversity in Texas.

During the summer of 2013, collection of glossiphoniid leeches from turtles in southern New England U.S.A. revealed several new host associations and geographic distribution records. Placobdella ali is reported for the first time from Massachusetts and Rhode Island. Placobdella hollensis is reported for the first time from mainland Rhode Island and for the first time from the common snapping turtle (Chelydra serpentina) and the stinkpot turtle or common musk turtle (Sternotherus odoratus). Helobdella papillata and Helobdella modesta were collected from common snapping turtles, and Helobdella lineata was collected from a stinkpot turtle. Data on the frequency of association of Helobdella spp. with aquatic vertebrates suggest that although Helobdella spp. are not parasitic, a symbiotic relationship likely exists between Helobdella spp. and their hosts, the nature of which is yet to be elucidated.

Rathke’s gland secretions (RGS) of Common Musk Turtles have a variety of proposed functions including predator deterrence and attraction, but experimental studies testing these hypotheses are lacking. This study used laboratory and field experiments to test whether RGS had attraction or repellent effects on two natural predators, the Cottonmouth (Agkistrodon piscivorus), and the Common Snapping Turtle (Chelydra serpentina). In a laboratory experiment, we examined latency to feed and consumption times for Cottonmouths offered RGS-treated minnows and control minnows. In a field study, we investigated the ratio of snapping turtles appearing in traps with and without RGS-treated bait. The latency to feed times for Cottonmouths offered RGS-treated minnows were not significantly different from those offered control minnows. However, prey consumption times for Cottonmouths feeding on RGS-treated minnows were significantly greater than those feeding on control minnows. These results suggest that the RGS may lengthen the time of a predation sequence, possibly allowing the turtle more time to escape from the predator. The number of snapping turtles appearing in traps with RGS-treated bait was significantly greater than the number of snapping turtles in traps without RGS-treated bait. These results support the predator attraction hypothesis, where the signal may attract additional predators that interfere with a predation event, providing an opportunity for the prey to escape.

Road networks threaten biodiversity and particularly herpetofauna, including common snapping turtles (Chelydra serpentina), which have an especially slow life history that prevents rapid recovery of populations subjected to road mortality. Cootes Drive is a 2.5-km 4-lane highway that bisects wetland habitat used for nesting and overwintering by snapping turtles. We hypothesized that turtle mortality from collisions with vehicles on Cootes Drive has caused a male bias and a decline in the population as turtles attempt to access habitat on both sides of the road. Capture–mark–recapture studies confirmed a dramatic decline in the turtle population from 941 individuals in 1985 to 177 individuals in 2002, a loss of 764 individuals in only 17 yrs. Using the same data, we also determined that the population has been significantly male-biased since 1985. Using 2009–2016 road mortality data obtained from the Dundas Turtle Watch (a citizen-science program), we completed a population viability analysis using the 2002 population size estimate to isolate the impact of road mortality. We found that this population is at risk of extirpation due to road mortality. The population range overlapped with the Cootes Drive and 7 of the 10 tracked turtles had individual home ranges that overlapped with the road. Our findings support the hypothesis that road mortality has contributed to the dramatic decline in the snapping turtle population in Cootes Paradise Marsh. This population is in jeopardy of extirpation; therefore, exclusion fencing must be installed for an extended distance along both sides of surrounding roads to prevent turtles from crossing the road and to promote their use of existing aquatic culverts.

Reptiles are declining worldwide yet our understanding of their immune function lags far behind other taxa. The innate immune system is the primary mode of defense in reptiles, and the serum complement cascade is its major component. We assessed serum complement activity of plasma in two closely related aquatic turtle species, the common snapping turtle (CST; Chelydra serpentina) and alligator snapping turtle (AST; Macrochelys temminckii). We used a sheep red blood cell (SRBC) hemolysis assay to assess serum complement activity. Although the antibacterial activities of the plasma of these turtle species are similar, the hemolytic activity was much stronger in CST than AST. Treatment with inhibitors of the serum complement cascade indicated differences in the mechanisms of complement activation between the turtle species. We subjected plasma from both turtle species to mannan affinity chromatography and analyzed the eluate with SDS-PAGE, which revealed that plasma from the CSTs contained only small amounts of one C-type lectin protein while the AST plasma contained high concentrations of two C-type lectins (31.0 and 35.9 kDa). Edman degradation analyses confirmed that the two AST proteins contained identical N-terminal sequences. Thus, the CST appears to rely more heavily on the alternative mechanism of serum complement activation, while the AST appears to rely more on the lectin-mediated pathway, which is a pattern recognition response to prokaryotes not activated by the SRBCs. These results are unique in that the use of serum complement pathways are generally assumed to be conserved within clades.

For some species of ectothermic vertebrates, early exposure to hypoxia during embryonic development improves hypoxia-tolerance later in life. However, the cellular mechanisms underlying this phenomenon are largely unknown. Given that hypoxic survival is critically dependent on the maintenance of cardiac function, we tested the hypothesis that developmental hypoxia alters cardiomyocyte physiology in a manner that protects the heart from hypoxic stress. To test this hypothesis, we studied the common snapping turtle, which routinely experiences chronic developmental hypoxia and exploits hypoxic environments in adulthood. We isolated cardiomyocytes from juvenile turtles that embryonically developed in either normoxia (21% O2) or hypoxia (10% O2), and subjected them to simulated anoxia and reoxygenation, while simultaneously measuring intracellular Ca2+, pH and reactive oxygen species (ROS) production. Our results suggest developmental hypoxia improves cardiomyocyte anoxia-tolerance of juvenile turtles, which is supported by enhanced myofilament Ca2+-sensitivity and a superior ability to suppress ROS production. Maintenance of low ROS levels during anoxia might limit oxidative damage and a greater sensitivity to Ca2+could provide a mechanism to maintain contractile force. Our study suggests developmental hypoxia has long-lasting effects on turtle cardiomyocyte function, which might prime their physiology for exploiting hypoxic environments.

Entanglement in or ingestion of fishing gear is a common cause of morbidity and mortality in chelonians. Commercial and recreational fishing activities exert bycatch pressures sufficient to cause population declines in the common snapping turtle (Chelydra serpentina) and the alligator snapping turtle (Macrochelys spp.). Gastrotomy for the removal of fish hook foreign bodies from the stomach of freshwater turtles typically requires a plastron osteotomy but in sea turtles has been successfully accomplished via soft tissue approaches. This study compared the anatomy and feasibility of soft tissue surgical approaches to the stomach in the common snapping turtle in both the prefemoral and the axillary regions. Anatomical dissections were performed on cadavers of five adult common snapping turtles, and the surgical anatomy of the left axillary and left prefemoral regions was characterized. The left axillary approach required extensive transection of musculature and provided poor exposure of the coelomic cavity and stomach. In contrast, the left prefemoral approach was simple to perform and provided sufficient access to the stomach for gastrotomy. The prefemoral celiotomy has significant advantages over the axillary celiotomy in the common snapping turtle and should be considered the surgical approach of choice for gastrotomy in this species.

In order to effectively manage urban habitats, it is important to incorporate the spatial ecology and habitat use of the species utilizing them. Our previous studies have shown that the distribution of upland habitats surrounding a highly urbanized wetland habitat, the Central Canal (Indianapolis, IN, USA) influences the distribution of map turtles (Graptemys geographica) and red-eared sliders (Trachemys scripta) during both the active season and hibernation. In this study we detail the movements and habitat use of another prominent member of the Central Canal turtle assemblage, the common snapping turtle, Chelydra serpentina. We find the same major upland habitat associations for C. serpentina as for G. geographica and T. scripta, despite major differences in their activity (e.g., C. serpentina do not regularly engage in aerial basking). These results reinforce the importance of recognizing the connection between aquatic and surrounding terrestrial habitats, especially in urban ecosystems.

Migratory and non-migratory Whooping Cranes (Grus americana) historically inhabited southwestern Louisiana until they were extirpated in 1950. Little is known about the feeding habits or dietary items of these cranes except for anecdotal evidence from local residents provided to R. P. Allen for his influential 1952 work on Whooping Cranes. Other populations of Whooping Cranes have been characterized as opportunistic omnivores, consuming small vertebrates, invertebrates, and plant material. In 2009, southwestern Louisiana was selected as a reintroduction site for Whooping Cranes. We report on four observations of reintroduced Whooping Cranes depredating at least two different species of turtles (common snapping turtle and mud turtle), which have not been previously reported as a dietary item for this species.

We captured 32 Common Snapping Turtles (Chelydra serpentina) in a Canaan Valley, West Virginia lake and equipped them with radio-transmitters during 1988 through 2007 to describe their hibernation behavior and examine the relative importance of temporal and environmental effects on hibernation. We monitored entry date, exit date, and location of hibernacula. The mean date of entry into hibernation was 9 October, and the mean date of exit from hibernation was 13 April, with a mean duration of 185 days. Turtles moved a mean distance of 117 m to hibernacula and were located most often along small streams bordered by speckled alder (Alnus rugosa). Hibernation entry date was influenced by lake temperature and hibernation exit date was influenced by water temperature at hibernacula sites. We suggest that small streams are important to Common Snapping Turtles as hibernacula because they provide protection from predators and remain above freezing temperatures.

Habersack, Mathew J., Theo A. Dillaha, and Charles Hagedorn, 2011. Common Snapping Turtles (Chelydra serpentina) as a Source of Fecal Indicator Bacteria in Freshwater Systems. Journal of the American Water Resources Association (JAWRA) 47(6):1255–1260. DOI: 10.1111/j.1752-1688.2011.00572.x Abstract: The United States Total Maximum Daily Load program is required by Section 303(d) of the Clean Water Act to clean up waters that do not meet state water quality standards. While conducting research into the bacterial composition of semiaquatic mammal feces, the opportunity presented itself to quantify commonly used pathogen indicator bacteria in the gastrointestinal contents from an ectothermic (cold-blooded) animal, the common snapping turtle. Indicator bacteria concentrations were on the order of 106 CFU/g feces (dry weight basis). The estimated bacterial loadings from this study demonstrate that the common snapping turtle, if present in sufficient numbers, may contribute significant bacterial loadings to waterways and should be considered when developing bacterial Total Maximum Daily Loads and in other bacterial water quality assessments.

Twenty-three turtles representing 3 families (5 species)—Chelydridae: common snapping turtle, Chelydra serpentina; Emydidae: brown wood turtle, Rhinoclemmys annulata; painted wood turtle, Rhinoclemmys pulcherrima; Kinosternidae: white-lipped mud turtle, Kinosternon leucostomum; scorpion mud turtle, Kinosternon scorpioides—collected in the Area de Conservacion Guanacaste, Costa Rica, were subjected to postmortem examination. Gravid nematodes representing 10 species, 9 previously described—Atractis costaricaensis, Cosmocercoides variabilis, Dracunculus globocephalus, Falcaustra chelydrae, Falcaustra tikasinghi, Klossinemella caballeroi, Sauricola sauricola, Serpinema magathi, Spiroxys figueiredoi—were found. Eight new host records and 7 new locality records are reported. A new species of Falcaustra inhabiting Rhinoclemmys annulata is described; it is the only known member of the genus lacking a pseudosucker, but having a toothed chamber separating the vestibule and the pharynx. Only Falcaustra kins...

The identification of predators of aquatic birds can be difficult. The Common Snapping Turtle (Chelydra serpentine) is considered a major predator of waterfowl and other aquatic birds, but the evidence for this reputation is based largely on circumstantial or indirect evidence rather than direct observations. Herein, the first documented observations of a snapping turtle attacking and killing an adult Western Grebe (Aechmophorus occidentalis) are described.

Carbon dioxide (CO2) laser was used to treat multiple cutaneous papillomas on an adult female common snapping turtle, Chelydra serpentina serpentina. A combination of excisional and ablative techniques provided excellent intraoperative visibility and postoperative results due to the laser's unique ability to incise and vaporize soft tissue.

There are currently few harvest regulations for the Common Snapping Turtle (Chelydra serpentina) in West Virginia. Uncontrolled harvest of long-lived species with delayed sexual maturity may lead to long-term declines in populations. We analyzed a 17-year data set from a mark-recapture study on an unharvested population of the Common Snapping Turtle in Canaan Valley, West Virginia. We captured 91 snapping turtles (47 female, 44 male). Program MARK was used to analyze 10 competing models predicting adult Common Snapping Turtle survival and capture probabilities and compared the models using Akaike Information Criterion values corrected for small sample size (AICc). The estimated annual survival was 0.97 and the annual capture probability was 0.11. We found that the best performing model involved constant survival and capture probability that varied based on the mass at initial capture. This suggests that there is no difference in survival between males and females. Moreover, the size of trap may a...

Chelydra serpentina (Common Snapping Turtle) is a wide-ranging and often abundant turtle species in the eastern United States, but relatively little is known of its basic ecology in the Southeast. The objective of our study was to examine the ecology and population biology of and describe the morphology of Common Snapping Turtles in northwestern Florida. We intensively sampled five localities in Leon County, FL using traps and hand collection (n = 111), and we also opportunistically collected Common Snapping Turtles as we encountered them through the course of other studies (n = 11). Analysis of seven morphological characters from a subset of individuals indicated that the Common Snapping Turtle in this study is an intergrade between C. s. serpentina and C. s. osceola. Estimated early growth rates were 20 mm carapace length (CL)/year, and females matured at about 220 mm CL (156 mm PL, approximately 6-8 years). Male Common Snap- ping Turtles (CL mean = 299 ± 6 mm) were larger than females (CL mean = 270 ± 5 mm), and the overall adult sex ratio was 1:1. Diet consisted primarily of aquatic plants (n = 4). Nesting females were found from early April through mid-May, and clutch size ranged from 5 to 49 eggs (n = 3). Common Snapping Turtle abundance varied over the five sites, but was highest (an average density of 16 individuals/ha) in small suburban ponds with abundant aquatic vegetation, a thick layer of organic sediment, and no alligators. In northwestern Florida, predation by alligators and humans and primary productivity appear to be the factors that influence the distri- bution and abundance of Common Snapping Turtles.

A free-living adult common snapping turtle, Chelydra serpentina, was presented to a wildlife care facility with an ulcerated expansive mass on the left side of its head and neck. Surgical exploration and excision of the mass revealed a necrotic plug of tissue, possibly auricular in origin. The mass was described histopathologically as being necrotic with laminations of tissue layers. Microbiology of samples collected from the lesion supported a diagnosis of bacterial granuloma.

Atrazine and glyphosate are two of the most common pesticides used in the US Midwest that impact water quality via runoff, and the common snapping turtle (Chelydra serpentina) is an excellent indicator species to monitor these pesticides especially in lotic systems. The goals of this study were to (1) quantify atrazine, the atrazine metabolite diaminochlorotriazine (DACT), and glyphosate burdens in common snapping turtle tissue from individuals collected within the Embarras River in Illinois; (2) quantify atrazine, DACT, and glyphosate loads in water from the aquatic habitats in which common snapping turtles reside; and (3) investigate tissue loads based on turtle morphology and habitat choice. Concentrations of atrazine, DACT, and glyphosate in tissue did not show any relationship with lake habitat, carapace length, width, or mass. Both atrazine and glyphosate tissue samples varied as a function of site (river vs. lake), but DACT did not. Atrazine and glyphosate concentrations in water samples showed a linear effect on distance from the reservoir spillway and a deviation from linearity. Water column concentrations of all three contaminants varied across capture sites, but atrazine water concentration did not influence DACT water concentration nor did it exhibit a site interaction. Water atrazine and glyphosate concentrations were greater than tissue concentrations, whereas DACT water and tissue concentrations did not differ. This study showed that turtles are useful in long-term pesticide monitoring, and because DACT as a metabolite is less sensitive to variation, it should be considered as a preferred biomarker for pesticide runoff.

Turtles were collected from three habitats in the upper reach of Pool 20, Mississippi River-open river, slough, and backwater. One hundred thirty-nine turtles of six species were examined for epizoites, but only red-eared slider (Trachemys scripta), common snapping turtle (Chelydra serpentina), painted turtle (Chrysemys scripta), and softshelled turtles (Apolone spp.) were collected in sufficient numbers for data analysis. Five epizoites were attached directly to turtles, including three leech species of the genus Placobdella, algae of the genus Basicladia, and the protozoan Vorticella sp. All hard shelled turtle species carried all five epozoites, but softshelled species carried only Placobdella multilineata, P. ornata, and Vorticella sp. The highest infestation rates occurred on snapping turtles with 94% leeches, 94% algae, and 48% Vorticella sp. The lowest rates for each group of epizoites were for the painted turtle with 26% leeches and softshelled turtles with 0% algae and 5% Vorticella sp. ...

We studied turtle populations inhabiting a canal and a lake (both man-made) within a heavily disturbed, urban setting. Six aquatic and semi-aquatic turtle species were collected in both habitats: spiny softshell turtle (Apolone spinifera), painted turtle (Chrysemys picta), common snapping turtle (Chelydra serpentina), common map turtle (Graptemys geographica), common musk turtle (Sternotherus odoratus) and red-eared slider (Trachemys scripta). While G. geographica was the most common species in the canal habitat, T. scripta was most common in the lake habitat. We describe patterns of sexual size dimorphism and sex ratios for the three most abundant species (G. geographica, T. scripta and S. odoratus). We discuss our data in light of problems facing turtle assemblages in urban settings.

Turtle community composition was determined in three habitats—open river, slough, and backwater—of the Mississippi River near Hamilton, Illinois. While seven species of turtles were collected during the study, distinct communities were found in each of the habitats. The open river site was dominated by female smooth softshell turtles, Apalone muticas, which made up approximately 80% of the community in this habitat. While turtles were abundant in the backwater habitat, only three species, red-eared slider (Trachemys scripta), common snapping turtle (Chelydra serpentina), and painted turtle (Chrysemys picta), were collected. Though all three species were common in the backwater, the red-eared slider was the most abundant. The habitat with the most abundant and diverse turtle community was the slough. In addition to red-eared sliders, the most abundant species collected, common snapping turtles, painted turtles, smooth softshell turtles, spiny softshell turtles (Apalone spinifera), common map turtl...

Filamentous algae are often visible on the carapaces of freshwater turtles and these algae are dominated by a few species with varying geographic distributions. Compared to filamentous algae, little is known about the much more speciose microalgae on turtles. Our objectives were to compare the diatom flora on a single turtle species (the common snapping turtle, Chelydra serpentina) across part of its range to examine spatial patterns and determine whether specific diatom taxa were consistently associated with turtles (as occurs in the filamentous alga Basicladia spp.). Using preserved turtle specimens from museums, we systematically sampled diatoms on the carapaces of 25 snapping turtles across five states. The diverse diatom assemblages formed two groups–the southern Oklahoma group and the northern Illinois/Wisconsin/New York group, with Arkansas not differing from either group. Of the six diatom species found in all five states, four species are widespread, whereas Luticola cf. goeppertiana and L. cf. mutica are undescribed species, known only from turtles in our study. L. cf. goeppertiana comprised 83% of the diatom abundance on Oklahoma turtles and was relatively more abundant on southern turtles (Oklahoma and Arkansas) than on northern turtles (where mean abundance/state was > 10%). L. cf. mutica was the most abundant species (40%) on New York turtles. Some Luticola species are apparently turtle associates and results support a pattern of spatial variation in Luticola species, similar to that in Basicladia. Using museum specimens is an efficient and effective method to study the distribution of micro-epibionts.

Individual variation in physiological traits may have important consequences for offspring survivorship and adult fitness. Variance in offspring phenotypes is due to interindividual differences in genotype, environment, and/or maternal effects. This study examined the contributions of incubation environment, maternal effects, and clutch identity to individual variation in metabolic rates in the common snapping turtle, Chelydra serpentina. We measured standard metabolic rate, as determined by oxygen consumption, for 246 individuals representing 24 clutches at 15° and 25°C, and we measured standard metabolic rates additionally for 34 individuals at 20° and 30°C. Standard metabolic rate for 34 snapping turtles measured at 15°, 20°, 25°, and 30°C increased with increasing temperature. Mean standard metabolic rate for 246 individuals was 0.247 μL O2 min−1 g−1 at 15°C and 0.919 μL O2 min−1 g−1 at 25°C. At 15°C, mass at hatching, individual mass, and egg mass had no significant effects on metabolic rate...

From the Great Lakes basin, concentrations of 59 congener-specific polychlorinated biphenyls (PCBs) and 14 organochlorine pesticides were measured in blood plasma of northern water snake (Nerodia sipedon sipedon) and Lake Erie water snake (Nerodia sipedon insularum), which is endangered in Canada. In 1998, four male adult Lake Erie water snakes were sampled from Pelee Island, western Lake Erie; four male northern water snakes were sampled at Little Lake, about 20 km north of Parry Sound in central Ontario; and four adult gravid female northern water snakes were sampled from Garden Island, eastern Lake Ontario. The blood plasma was pooled by site for a total of three samples analyzed. The Pelee Island sample from male Lake Erie water snakes contained less than half the lipid concentration (0.349%) than samples from the other sites, but it was the most contaminated with PCBs, even on a wet weight basis. Summed concentration of individual PCBs in the Pelee Island sample was 167 ng/g (wet weight), which was 14-fold higher than the next most contaminated sample, which was from Little Lake. The plasma sample from Little Lake contained 12 ng/g (WW) and was four times more contaminated with PCBs than the sample from female snakes from Garden Island, Lake Ontario. Organochlorine pesticide concentrations in plasma were relatively similar among sites. None of the pesticides was found above trace concentrations (0.1-0.9 ng/g) except pp'-DDE, which occurred at 2-5 ng/g among sites. PCB congener patterns in the Lake Erie water snakes were compared to PCB patterns in plasma of common snapping turtle (Chelydra serpentina serpentina) from Lake Ontario, herring gull eggs (Larus argentatus) from western Lake Erie, and mudpuppy eggs (Necturus maculosus) from the Detroit River. The PCB patterns in water snake and herring gull sample were most similar, followed by the pattern in snapping turtle plasma. The presence of more lower-chlorinated chlorobiphenyls in the mudpuppy eggs relative to the other species made this sample distinct from the water snake, gull, and turtle.

Individual variation in physiological traits may have important consequences for offspring survivorship and adult fitness. Variance in offspring phenotypes is due to interindividual differences in genotype, environment, and/or maternal effects. This study examined the contributions of incubation environment, maternal effects, and clutch identity to individual variation in metabolic rates in the common snapping turtle, Chelydra serpentina. We measured standard metabolic rate, as determined by oxygen consumption, for 246 individuals representing 24 clutches at 15 degrees and 25 degrees C, and we measured standard metabolic rates additionally for 34 individuals at 20 degrees and 30 degrees C. Standard metabolic rate for 34 snapping turtles measured at 15 degrees, 20 degrees, 25 degrees, and 30 degrees C increased with increasing temperature. Mean standard metabolic rate for 246 individuals was 0.247 microL O(2) min(-1) g(-1) at 15 degrees C and 0.919 microL O(2) min(-1) g(-1) at 25 degrees C. At 15 degrees C, mass at hatching, individual mass, and egg mass had no significant effects on metabolic rate, but at 25 degrees C, mass at hatching, individual mass, and egg mass did have significant effects on metabolic rate. Incubation temperature had no significant effect on metabolic rate at 15 degrees, but it did have a significant effect at 25 degrees C. Clutch identity had a significant effect on metabolic rate at both 15 degrees and 25 degrees C. Interindividual variation in standard metabolic rate due to incubation temperature, and especially clutch identity, could have large effects on energy budgets. Results suggest that there were both environmental and genetic effects on standard metabolic rate.

Much of the demand for turtle meat in North America and Europe during the past four centuries has been met using green turtle (Chelonia mydas) and other marine turtles. As stocks of marine turtles dwindled, harvest of the alligator snapping turtle (Macroclemys temminckii), the largest freshwater turtle in North America, increased in the south-eastern USA. As a result, this species has declined and is now protected in every state of the USA except Louisiana. There is concern that the remaining legal trade in turtle products may serve as a cover for illegally harvested species. To assess the composition of species in commerce, we purchased 36 putative turtle meat products in Louisiana and Florida. Using cytochrome b and control region sequences of the mitochondrial genome, we identified 19 samples as common snapping turtle (Chelydra serpentina), three as Florida softshell (Apalone ferox), one provisionally as softshell turtle (Apalone sp.), one as alligator snapping turtle, and eight as American alligator (Alligator mississippiensis). It appears that M. temminckii is no longer the predominant species in markets of Louisiana. The presence of alligator meat in a quarter of the samples indicates that the trade in turtle products is not entirely legitimate. As is often the case for unsustainable wildlife harvests, large, esteemed species, such as green turtle and alligator snapper, have been replaced by smaller, more-abundant or mislabelled species, a phenomenon we refer to as the mock turtle syndrome.

Embryonic temperature influenced subsequent growth in juvenile snapping turtles, Chelydra serpentina: incubation temperatures of 24 and 26.5°C enhanced growth relative to a temperature of 29°C. Although embryonic temperature normally determines gonadal sex in this species, experimental manipulations revealed that temperature effects on growth were independent of sex. Ambient temperature also affected growth: juvenile turtles grew slowly in a cool (19°C) versus a warm (28°C) environment. In a parallel experiment, turtles from different embryonic temperatures displayed different patterns of temperature choice in response to nutritional status or time of day. We tentatively conclude that embryonic temperature has both direct and indirect (i.e., through temperature choice) effects on growth in snapping turtles.

Unlike birds and mammals, in many reptiles the temperature experienced by a developing embryo determines its gonadal sex. To understand how temperature-dependent sex determination (TSD) evolves, we must first determine the nature of genetic variation for sex ratio. Here, we analyze among-family variation for sex ratio in three TSD species: the American alligator (Alligator mississipiensis), the common snapping turtle (Chelydra serpentina) and the painted turtle (Chrysemys picta). Significant family effects and significant temperature effects were detected in all three species. In addition, family-by-temperature interactions were evident in the alligator and the snapping turtle, but not in the painted turtle. Overall, the among-family variation detected in this study indicates potential for sex-ratio evolution in at least three reptiles with TSD. Consequently, climate change scenarios that are posited on the presumption that sex-ratio evolution in TSD reptiles is genetically constrained may require reevaluation.

Previous studies of relationships among the subspecies of snapping turtles (Chelydra serpentina} based on morphological and osteological characters have been inconclusive. We investigated relationships among the four currently recognized subspecies using restriction endonuclease fragment patterns of mtDNA and protein electrophoresis. Sixteen six-based recognizing restriction endonucleases yielded 90 variable fragments that define 11 different haplotypes. Individuals of the two North American subspecies, C. s. osceola and C. s. serpentina, are closely related, differing by a maximum of 0.5% sequence divergence. The Central American subspecies, C. s. rossignonii and C. s. acutirostris, are more distinct, both from each other (a minimum of 1.7% sequence divergence) and from the North American samples (an average of 4.45% sequence divergence). The degree of allozymic variation among the four subspecies was found to be limited and could not be used to diagnose the four recognized subspecies. The mtDNA data presented here support the species-level distinctness of C. s. rossignonii and C. s. acutirostris from each other and from a C. s serpentina-C. s. osceola complex. The recognition of three distinctive groups of Chelydra rather than one widespread polytypic species has important conservation implications because it focuses attention on the poorly known middle and South American species. Estudios previos sobre las relaciones entre las subespecies de la tortuga Chelydra serpentina, basados en caracteres morfologicos y osteologicos no han sido concluyentes. En el presente estudio investigamos la relacion entre cuatro subespecies reconocidas en la actualidad usando patrones de fragmentos de endonucleasas de restriccion de ADN mitocondrial y electroforesis de enzimas. Dieciseis endonucleasas de restriccion que reconocen 6 bases proveyeron 90 fragmentos variables que definen 11 haplotipos diferentes. Los individuos de dos especies de Norte America, C. s. osceola y C. s. serpentina, estan relacionados estrechamente, difiriendo en un maximo de 0.5% de divergencia de secuencias. Las especies de America Central, C. s. rossignonii y C. s. acutirostris, son mas distintas entre si (con un minimo de 1.7% de divergencia de secuencias) y distintas del complejo C. s. serpentina-C. s. osceola. El reconocimiento de tres grupos distintivos de Chelydra en lugar de una especie politipica de amplia distribucion tiene importantes implicaciones para la conservacion, debido a que enfoca la atencion en las especies menos conocidas de Meso y Sud America.

Although the common snapping turtle Chelydra serpentina is cultured commercially in the United States, little information is available on nutritional and culture requirements. This study was conducted to evaluate the effects of dietary energy: protein ratio and stocking density on survival, growth, feed consumption, feed conversion, liposomatic index, dress-out percentage, and productive protein value of cultured, common snapping turtles. Hatchling turtles were stocked at 29 and 58 animals/m2 and fed one of seven prepared diets. Six diets contained 30, 35, or 40% protein at two digestible energy (DE) levels (7 or 9 kcal DE/g protein); the seventh was a reference diet (66% protein and 5 kcal DE/g protein) formulated to equal or exceed the whole-body essential amino acid composition of wild, common snapping turtles. Turtles stocked at 58/m2 exhibited greater mortality, lower weight gain, higher feed consumption, less-efficient feed conversion, lower liposomatic index, and lower productive protein value than turtles stocked at 29/m2 (P < 0.05). The reference diet produced the greatest weight gain (P < 0.001). The superior performance of turtles fed the reference diet suggests that: 1) the protein (amino acid) content and/or energy: protein ratio of the reference diet was superior to that of the other diets tested; 2) improvements in growth parameters can be made with dietary manipulation; and 3) high levels of plant protein can be used in prepared, snapping turtle diets.

Abstrcact.-We examined a critical component of the Charnov-Bull hypothesis of temperaturedependent sex determination (TSD) by determining the reaction norms of hatchling growth to embryonic incubation temperature in the common snapping turtle, Chelydra serpentina. Hormone manipulations of eggs produced females at male temperatures and vice versa, which thereby permitted same-sex comparisons of hatchling growth across a range of incubation temperatures. In this way, the normally confounded effects of incubation temperature and sex were dissociated experimentally. The resultant hatchlings, including controls and experimentals, exhibited normal gonadal structure and sex steroid profiles. The subsequent growth of hatchlings monitored for 6 mo was strongly affected by embryonic incubation temperature but not by sex. As predicted, growth was enhanced at incubation temperatures that produced males. Clutch effects and interaction effects (clutch by incubation temperature) on growth were significant. In addition, there was a positive genetic covariance among incubation temperatures, but incubation temperature effects varied among clutches. The variation in growth plasticity among clutches was consistent with Charnov-Bull predictions. In this TSD species, incubation temperature is likely to have differential fitness effects on the sexes mediated via differences in growth.

The evolutionary significance of sex-determining mechanisms, particularly temperature-dependent sex determination (TSD) in reptiles, has remained unresolved despite extensive theoretical work. To investigate the evolutionary significance of this unusual sex-determining mechanism, I incubated eggs of the common snapping turtle (Chelydra serpentina) at a male-producing temperature (26°C), a female-producing temperature (30°C), and an intermediate temperature that produced both sexes about equally (28°C). Laboratory experiments indicated that two performance variables, but no morphological measurements, were significantly influenced by incubation temperature (P ≤ 0.05): hatchlings from cooler incubation treatments swam faster than turtles from warmer incubation treatments, and hatchlings from 28°C exhibited a greater propensity to run than did individuals from 26°C and 30°C. In the field, hatchlings from the all-male and all-female producing temperatures had significantly higher first-year survivorship than did consexuals from the incubation temperature that produced both sexes (G = 6.622, P = 0.03). Significant directional selection was detected on propensity of hatchlings to run (β' = -0.758, P = 0.05): turtles that tended to remain immobile had a higher probability of first-year survivorship than did individuals that moved readily. Thus, the effects of the gender × incubation temperature interaction on survivorship of hatchling turtles observed in the field experiment may have been mediated by temperature-dependent antipredator behavior. These results provide a possible functional explanation for the evolutionary significance of TSD in turtles that is consistent with predictions of theoretical models.