Leatherback turtles in the Pacific Ocean have declined precipitously in recent decades. One issue that may be contributing to the declines of leatherbacks and impairing their recovery is low clutch viability resulting from high embryonic mortality. Here, we examine trace metal concentrations in eggs and hatchlings from leatherbacks nesting on the Pacific coast of Costa Rica to assess whether contaminant levels reflect variation in the time over which females accumulated contaminants and whether variation in egg contaminant concentrations among nests influences clutch viability and hatchling characteristics. Eggs and hatchlings of Pacific leatherbacks contained detectable concentrations of a suite of essential and nonessential metals including Cu, Cd, Fe, Mn, Ni, and Zn, but variables that likely reflect a female's degree of temporal exposure to contaminants (relative age of female, body size, and remigration interval) explained little of the variation in egg metal concentrations. Concentrations of Cu, Cd, Fe, and Ni in Pacific leatherbacks were higher or toward the upper range of metal levels examined in sea turtle eggs elsewhere, but we did not find evidence linking egg contaminant levels with clutch success or hatchling size or body condition. These results represent the most comprehensive measures of trace metal concentrations from leatherback turtles in the eastern Pacific Ocean.

The courtship behavior of male Greek tortoises (Testudo graeca) is based on a multiple signaling system that involves tactile, visual, olfactory, and acoustic signals. In some recent studies on marginated (Testudo marginata) and Hermann's tortoises (Testudo hermanni) we showed that male mounting success was significantly and positively correlated to the intensity of courtship displays. This was due to the number of rams and bites and the number of calls emitted during mounting, which are considered to be condition-dependent signals that reliably convey information on male quality. In this correlative study, we analyzed relationships between male morphology, hematological profile, courtship intensity, vocalizations, and mounting success in a group of 104 Greek tortoises breeding in seminatural enclosures. As expected, our study showed that mounting success of males was positively correlated to the number of rams and the frequency of interactions during courtship and negatively correlated to the call duration. Moreover the hematocrit was positively correlated with the call rate and the number of rams. Therefore, courtship signals exhibited by male Greek tortoises, including vocalizations, reliably reveal different components of male condition, and females may use these signals to choose high-quality partners, as previously observed in marginated and Hermann's tortoises.

Effective management of migratory sea turtles requires informed and sustained collaboration among range states. The primary objective of the Wider Caribbean Sea Turtle Conservation Network's regional Marine Turtle Tagging Centre at the University of the West Indies, Barbados, has been to encourage and enable such collaboration, uniting otherwise isolated sea turtle tagging programs to benefit from information on the geographic range of sea turtles tagged in one country and captured, sighted, or stranded in another country. We present the first summary of information gleaned from international tag returns of adult female hawksbill sea turtles (Eretmochelys imbricata) marked with Marine Turtle Tagging Centre tags. Twenty-one sea turtle projects in 19 countries and overseas territories received Inconel 1005–681 tags from the Marine Turtle Tagging Centre between January 2002 and June 2009, and 12 of these projects have reported tagging adult female hawksbills, for a combined total of 2261 tagged individuals. Sixty-three of these individuals (2.8%), sighted at least once in another country since being tagged, have been reported to the Marine Turtle Tagging Centre; the majority of them (96.8%) were originally tagged while they were nesting in Barbados. Based on minimum straight-line distance traveled, the point of capture averaged 343.9 ± 69.7 km standard error (SE), (median 175 km) from the nesting beach. The average number of days between tagging and the first recapture was 835 ± 67.9 days SE, median 860 days). Although the majority of returns came from within a few hundred kilometers of the tagging site, tagged animals often passed through multiple exclusive economic zones and were exposed to conflicting management regimes, which include legal and illegal sea turtle fisheries. The shallow continental shelf off the coasts of Nicaragua and Honduras was confirmed as a foraging ground for Eastern Caribbean hawksbills.

We report on data collected during the first long-term turtle monitoring and conservation program conducted in the Amirantes Islands Group of Seychelles. Green turtle (Chelonia mydas) and hawksbill (Eretmochelys imbricata) nesting activity was recorded on a daily basis, year-round, over a period of 62 months between November 2004 and December 2009 at D'Arros Island, in the context of a community-based turtle monitoring and conservation program coordinated by the D'Arros Research Centre (DRC). Green turtle nesting occurred year-round with a distinct peak in late March but also evidence of a bimodal pattern with a dominant peak during February to April and a secondary peak in July and August. For hawksbills, nesting peaked in early December, with 94.0% of nesting emergences during the four-month interval from 1 October to 31 January. Along the 5-km nesting beach, the estimated average number of clutches laid annually was 95 for green turtles (range 65–120) and 300 (range 277–318) for hawksbills. Assuming an average of 5 clutches annually for green turtles and 4–5 for hawksbills, this would represent some 20 green turtles and 60–75 hawksbill females nesting annually. This indicates an increase in nesting activity—but not necessarily in numbers of nesting females—from that reported in the early 1970s, early 1980s, and mid-1990s when exploitation was intense. During the 5 years that the DRC turtle conservation and monitoring program was underway, turtle poaching has virtually ceased at D'Arros Island and adjacent St. Joseph atoll.

Comparison of the resource accumulation patterns exhibited by related species inhabiting disparate hydrological conditions can provide insight into how they are affected by and respond to different environments. We compared the seasonal body condition of the desert tortoise (Gopherus agassizii) in the Mojave Desert with that of the gopher tortoise (Gopherus polyphemus) in central Florida. We assessed body condition indirectly, with indices derived from the relationship between body mass and size. In turtles, variation in body mass largely reflects tissue hydration, water stored in the bladder, and food stored in the gut. Mean body condition was lower and seasonal fluctuations were of lesser amplitude in the gopher tortoise than in the desert tortoise. Over the short term, body condition of the desert tortoise is correlated strongly with rainfall, but body condition of the gopher tortoise is not. These differences between the two species are consistent with what is known about their physiology and behavior under current climatic conditions. Changing rainfall patterns may severely affect the desert tortoise. The physiological reaction of the gopher tortoise to drought conditions also may put it at substantial potential risk from climate change.

We examined the orientation of 76 naïve painted turtles (Chrysemys picta belli) and 746 snapping turtles (Chelydra serpentina) during initial dispersal from experimental nests in the Weaver Dunes area of southeastern Minnesota. We conducted 15 releases into large circular arenas in 4 natural nesting areas and 2 atypical areas. Hatchling orientation and dispersal for both species were 1) all nonrandom, 2) appeared to be based on vision (i.e., nonpolarized light), and 3) toward nearby, open, and highly illuminated horizons, regardless of whether or not they were associated with the wetlands. A first-order estimate of hatchling snapping turtle perception distance was 55–90 m. We found no evidence that suggests that specular light from the wetlands, olfaction, or humidity gradients were important in orientation. At 2 of 3 locations, substantial changes in orientation direction occurred when hatchling snapping turtles were released in morning vs. late afternoon. Changes in dispersal directions in the morning and afternoon indicated that hatchlings were not orienting toward the sun per se but toward different highly illuminated nearby prairie areas. At one site, hatchling orientation in the afternoon (but not in the morning) was toward a nearby wetland and was consistent with either dispersal toward highly illuminated near horizon or with the perception and use of reflected polarized light from the wetland. Collectively, the results from our study also indicate that 1) hatchlings disperse toward open horizons rather than toward wetlands themselves (i.e., open areas that are not necessarily associated with wetlands), 2) dispersal direction is influenced by time of day, apparently because of changes in the degree of illumination of different horizons, and 3) far horizons apparently were not used because they were beyond the perception distance of hatchlings. The most parsimonious evolutionary explanation of solutions to orientation problems is that, for each species, both adults and hatchlings have similar perception distances and use the same sensory modes and types of environmental cues during terrestrial movements. Comprehensive conservation and management plans for aquatic turtles should include consideration of how habitat changes in nesting areas might alter the environmental cues that determine the initial orientation and successful dispersal of hatchlings. We compared the results from this study with the dispersal patterns of naïve hatchling Blanding's turtles (Emydoidea blandingii) that emerge from nests located much farther from wetlands.

Miniature temperature loggers were used to better understand the incubation temperatures, patterns in metabolic heating, and potential implications for sex determination of relocated and in situ loggerhead sea turtle clutches near the northern extent of their nesting range. All sea turtles display temperature-dependent sex determination, with cooler nests producing males and warmer nests producing females. Analysis of the factors that affect incubation temperatures provides insight into variation in hatchling sex ratios over temporal and spatial scales and may help to guide management measures for the imperiled loggerhead sea turtle. Although no temperature difference was detected between relocated and in situ clutches during the thermal sensitive period, relocated nests hatched more quickly and incubated at warmer temperatures than in situ clutches for the entire incubation period. Metabolic heating was apparent in all clutches, beginning during the middle third of incubation, with the greatest gradient between nest temperature and surrounding sand temperatures (x ¯  =  1.5 ± 0.05°C) that occur during the final third of incubation. The magnitude of metabolic heating was not different between relocated and in situ clutches. Diel temperature fluctuations within nests were significantly less pronounced than in adjacent sand, which implies a degree of thermal buffering within the nest chamber. During the thermosensitive period, all nests incubated at a mean temperature above that of the estimated pivotal temperature (29.2°C), which implies a strongly female-biased hatchling sex ratio during the portion of the nesting season monitored. Potential impacts on incubation temperature and resultant sex ratios should be considered and explored on a beach-by-beach basis before adopting nest relocation as a conservation measure.

We investigated the effects of the order of sequential matings in captive female loggerhead turtles (Caretta caretta) on the paternity of their successive clutches. Paternity analysis revealed that only 3 of the 7 successive clutches were multiply sired, although all egg-laying females were observed to copulate with multiple males prior to egg-laying. In multiply sired, successive clutches of particular females, the relative paternal contributions of different males did not vary, although some potentially successful matings were observed during internesting intervals. Prior to nesting periods, males showed mating in response to the female reproductive cycle in which the cumulative durations of mountings observed by highly sensitive cameras peaked at 21–40 days before any individual female laid her first clutch. A regression line between cumulative duration of mountings and relative parental contributions for 21–40 days before laying the first clutch fit a predictive equation for sperm competition based on the assumptions of a fair raffle. These results suggest that sperm precedence has changed with time over the course of a prenesting period and that male turtles in this study have regulated the timing of copulations in accordance with the patterns of sperm precedence.

Juvenile green turtles occupy home ranges on shallow reefs that parallel the southeastern coast of Florida. When disturbed, the turtles often flee eastward toward deeper water. We captured turtles at night and recorded their orientation during the next 2 days while they swam tethered inside a large circular outdoor pool and were exposed to the sun. The turtles from 2 reef sites were significantly oriented eastward. After 7–10 days of exposure to a laboratory photocycle advanced by 7 hours, turtles tested in the same pool were significantly oriented westward, the predicted direction if they used the sun for orientation. Westward orientation was unaffected by placing either disc magnets or brass discs of identical mass above the turtles' heads. These results are consistent with the hypothesis that orientation under clear skies is preferentially based upon solar cues. However, control turtles exposed for 7–10 days to a photocycle advanced by 1 hour were also expected to swim generally eastward, but, for unknown reasons, failed to show significant orientation. Our results therefore support the hypothesis that the sun is used as a compass, but additional experiments will be required to provide definitive evidence.

We estimated demographic parameters for Acanthochelys spixii in Parque Nacional de Brasí lia, Distrito Federal, Brazil, based on 4 years of data collection, and also analyzed the effects of sex, temporal variation, and climatic factors on population dynamics. The adult sex ratio did not vary significantly from 1∶1. By using the Akaike's information criterion, selection of candidate models constrained for climatic variables indicated that the interaction between total rainfall and average air temperature from the previous month as well as recapture probability (p) on a monthly basis explained most variation in demographic parameters, with a constant annual apparent survival (Φ) value of 0.82. Recapture rates during the study period varied from 0.01 to 0.23 and, during the dry season, from 0.01 to 0.04. The monthly average population size was 30 adult turtles, with values between 10 and 35 adults over 4 years. The annual population growth rates were 1.37 for 2005–2006 and 0.59 for 2006–2007. The small population size of Acanthochelys spixii seems characteristic of chelids in the area, and maintaining it depends on preserving natural ecosystems inside Parque Nacional de Brasília.

We studied the diet of Acanthochelys spixii in a wild population in the Cerrado of central Brazil for 19 months, investigating ontogenetic, sexual, and interindividual variation. The diet consisted mainly of nymphs of Odonata, although other insects, amphibians, and plant material were also present. We observed no ontogenetic shifts in diet composition (e.g., no shift from carnivorous juveniles to herbivorous adults), which can be related to the high abundance of prey at the study site. There was no association between prey size and turtle carapace length, with larger animals still taking small prey. Dietary niche overlap was high, and there was no difference in niche breadth between sexes. However, differences in diet composition suggested differential habitat use, with males using more the periphery and females using more the center of ponds. Diet composition varied more among males than among females, which can result from higher diversity of prey at the pond margins, higher movement rates, or larger home range of males. The high frequency of empty stomachs (41%) reflected life-history characteristics of turtles (e.g., low metabolism, ectothermy, late sexual maturity, and great longevity). The importance of prey categories sensitive to pollution in the diet of A. spixii highlights the integrity of the study sites and the vulnerability of these populations to the rapid degradation of Cerrado biome.

Growth patterns of captive-bred Seychelles–Aldabra giant tortoises (Aldabrachelys/Dipsochelys) were studied. This enabled the comparison of the development of 3 distinct morphotypes variously ascribed by different authors to 3 distinct species or a single, variable species (A./D. dussumieri/gigantea, arnoldi, and hololissa). Geometric morphometric analyses identified differences in growth pattern between the 3 morphotypes of 234 juvenile tortoises reared under identical conditions. In plastral characters, all 3 morphotypes could be distinguished from hatching. Initially, hatchlings were very similar in dorsal view but by 30-cm straight carapace length were distinguishable by relative warp analysis. The arnoldi morphotype is the most distinctive, with constriction in the center of the carapace resulting in the beginning of development of saddle-backed morphology from 30 cm. All 3 morphotypes show 2 distinct growth patterns, one from hatching to 20–30 cm and a different pattern above 30 cm. As these morphotypes were reared under identical, largely constant conditions, this change in growth patterns appears to be a result of ontogeny rather than environment. Differences in development of the morphotypes cannot be explained by environmental factors alone and may be the result of differences in gene expression or of small differences in genes associated with skeletal development.

Two geoemydid turtle species, Geoemyda spengleri and Cuora bourreti, are documented from Laos for the first time. The record of G. spengleri is based on photographs taken of a wild turtle by staff in a protected area in eastern Bolikhamxay Province, central Laos. Those of C. bourreti are based on our examinations of live turtles in the possession of a hunter and in a village in a remote area of eastern Savannakhet Province, southeastern Laos. Both localities lie near the border with Vietnam, where these species were previously known. Turtles are highly threatened in Laos from overexploitation for food and traditional medicine purposes, but the presence of G. spengleri and C. bourreti within protected areas offers hope for their persistence.

The goal of this study was to test the effectiveness of analyzing sex hormone profiles to sex green sea turtle (Chelonia mydas) hatchlings. To assess the efficacy of this method, 200 eggs of C. mydas were incubated at five different temperatures, and a chemiluminescent immunoassay system was used to determine the sex hormone profiles (estrogen and testosterone) in the amniotic fluid (from eggshells) and plasma of a subset of C. mydas hatchlings. Results were compared to a standard histological technique and revealed that evaluating sex hormone profiles from amniotic fluid is an effective, noninvasive technique for determining hatchling gender.

Culverts are often used to increase the permeability of roaded landscapes for wildlife, including turtles. Although the benefits of culverts as safe passages for turtles are well documented, under some conditions culverts can entrap them and cause mortality. Here we report a culvert-related mortality in the federally threatened desert tortoise (Gopherus agassizii) at a wind energy facility in California and offer simple recommendations to mitigate the negative effects of culverts for wildlife in general.

Nesting activity of a depleted population of the eastern Malay Peninsula river terrapin, Batagur affinis edwardmolli, in the Setiu River, Terengganu, Malaysia, is documented for the first time over a 6-year period (2004–2009). The number of clutches deposited per year ranged from 17 to 30 with annual average clutch sizes ranging from 23 to 30 eggs per clutch. The nesting season is brief, beginning at the end of January and continuing through March.

We studied the structure of a population of Hydromedusa maximiliani associated with a stream in Parque Estadual da Serra do Mar, Núcleo Itutinga-Pilões, southeastern Brazil, between October 2004 and October 2005. Twenty-five individuals were captured, and a population size of 43.72 ± 23.7 individuals was estimated. This value is similar to that of the population of Parque Estadual Carlos Botelho, another Atlantic forest reserve of southeastern Brazil. Males were recaptured more frequently than females, suggesting higher activity and/or greater movement of males.

The food habits of a freshwater pelomedusid turtle (Pelomedusa subrufa) were studied by fecal analysis and stomach flushing in 2 study areas in Nigeria. Males and females were predominantly carnivorous; they fed mainly on fish, tadpoles, and aquatic invertebrates but also on terrestrial vertebrates. Sexes overlapped highly in dietary habits during both wet and dry season. Body size clearly affected diet composition of turtles but did so only during the dry season (with smaller individuals feeding primarily on invertebrates and small vertebrates, and larger individuals on homeotherm vertebrates). There was a strong effect of season on diet composition, and turtles responded to increasing dryness with a shift from a diet based on aquatic organisms during the wet season to a diet based on terrestrial organisms, including small vertebrates, during the dry season.

While conducting a monitoring program in arid southwestern Madagascar we observed a large aggregation of ca. 100 radiated tortoises (Astrochelys radiata) along ca. 80 m of dry creek bottom at the onset of the wet season. Tortoises had apparently anticipated rainfall and as precipitation ensued, immediately began drinking from small depressions in the bedrock. We discuss potential mechanisms and consequences of the behavior and compare it with similar observations in desert tortoises (Gopherus agassizii).

We found 36 nests of Podocnemis erythrocephala in the lower Tapajós River in central Amazonia during 3 consecutive nesting seasons, from 2006 to 2009. The species nested from the end of the dry season to the start of the rainy season, nesting far from the water in savanna vegetation. Mean clutch size was 7 eggs (range, 5–11), mean incubation time was 66.8 days (range, 62–87), and hatching success rate was 0.69 (range, 0.27–1.0).

Although turtles are well protected by laws in Brazil, the laws are not enforced in some places and ignored in others. Based on 15 years of work in the Rio Negro Basin, we describe the history of turtle exploitation in this region, comment on their current conservation status, and suggest practical conservation alternatives that are necessary to preserve stable populations.