A comparison of three external transmitter attachment methods for snakes

Artificial shelters provide suitable thermal habitat for a cold-blooded animal

Human activities such as urbanization often has negative affects wildlife. However, urbanization can also be beneficial to some animals by providing suitable microhabitats. To test the impact of urbanization on cold-blooded animals, we first conducted a snake survey at a national nature reserve (Xianghai natural reserve) and an adjacent tourist bird park (Red-crowned Crane Park). We show high presence of Elaphe dione in the tourist park even with high human activities and predator population (the endangered, red-crowned crane, Grus japonensis). We then radio-tracked 20 individuals of E. dione, set seven camera traps, and recorded the temperature of the snakes and artificial structures in Crane Park to document their space use, activity, and thermal preference, respectively. Our results show E. dione preferred to use artificial facilities to shelter from their predators and for thermoregulation. The high number of rats from the camera traps indicate abundant prey items. Overall, E. dione appears to be adapted to modified habitats and may expand population size at the current study site.

Individual heterogeneity influences the effects of translocation on urban dispersal of an invasive reptile

BACKGROUND

Invasive reptiles pose a serious threat to global biodiversity, but early detection of individuals in an incipient population is often hindered by their cryptic nature, sporadic movements, and variation among individuals. Little is known about the mechanisms that affect the movement of these species, which limits our understanding of their dispersal. Our aim was to determine whether translocation or small-scale landscape features affect movement patterns of brown treesnakes (Boiga irregularis), a destructive invasive predator on the island of Guam.

METHODS

We conducted a field experiment to compare the movements of resident (control) snakes to those of snakes translocated from forests and urban areas into new urban habitats. We developed a Bayesian hierarchical model to analyze snake movement mechanisms and account for attributes unique to invasive reptiles by incorporating multiple behavioral states and individual heterogeneity in movement parameters.

RESULTS

We did not observe strong differences in mechanistic movement parameters (turning angle or step length) among experimental treatment groups. We found some evidence that translocated snakes from both forests and urban areas made longer movements than resident snakes, but variation among individuals within treatment groups weakened this effect. Snakes translocated from forests moved more frequently from pavement than those translocated from urban areas. Snakes translocated from urban areas moved less frequently from buildings than resident snakes. Resident snakes had high individual heterogeneity in movement probability.

CONCLUSIONS

Our approach to modeling movement improved our understanding of invasive reptile dispersal by allowing us to examine the mechanisms that influence their movement. We also demonstrated the importance of accounting for individual heterogeneity in population-level analyses, especially when management goals involve eradication of an invasive species.

Safe from sunburn: The divergent diel pattern of a Hydrophis sea snake

Diel activity patterns are an important aspect of wildlife ecology and evolution and provide valuable information for conservation and monitoring, yet for many species, activity patterns remain unstudied and may be presumed to mirror related taxa. Here, we describe the distinct diel patterns of an endemic population of venomous sea snakes Hydrophis platurus xanthos inhabiting a narrow range (circa 320 km2) in Golfo Dulce, Costa Rica. To investigate, we conducted a systematic visual survey over five 24-h cycles and evaluated 339 h of previously obtained sighting data from different studies spanning a decade. While sporadic diurnal surfacing does occur, mostly for respiration, our observations revealed marked crepuscular peaks with regular surfacing through the night. We also report on observed surface behaviors that were also found to vary in frequency at different phases of the photoperiodic cycle. In particular, we show feeding as more common at night. Hydrophis platurus xanthos has developed a circadian rhythm that differs noticeably from its taxonomic parent (H. p. platurus is reported as diurnal across its Indo-Pacific range), and no congeners have been categorized as crepuscular. Our work thus contributes to the ecological knowledge of this evolutionarily distinct marine elapid and offers insights into the potential role of environmental conditions in shaping animal activity.

A perspective view of top-down proteomics in snake venom research

The venom produced by snakes contains complex mixtures of pharmacologically active proteins and peptides which play a crucial role in the pathophysiology of snakebite diseases. The deep understanding of venom proteomes can help to improve the treatment of this "neglected tropical disease" (as expressed by the World Health Organization [WHO]) and to develop new drugs. The most widely used technique for venom analysis is liquid chromatography/tandem mass spectrometry (LC/MS/MS)-based bottom-up (BU) proteomics. Considering the fact that multiple multi-locus gene families encode snake venom proteins, the major challenge for the BU proteomics is the limited sequence coverage and also the "protein inference problem" which result in a loss of information for the identification and characterization of toxin proteoforms (genetic variation, alternative mRNA splicing, single nucleotide polymorphism [SNP] and post-translational modifications [PTMs]). In contrast, intact protein measurements with top-down (TD) MS strategies cover almost complete protein sequences, and prove the ability to identify venom proteoforms and to localize their modifications and sequence variations.

Impacts of translocation on a large urban-adapted venomous snake

Context Translocation as a tool for management of nuisance or ‘problem’ snakes near urban areas is currently used worldwide with limited success. Translocated snakes experience modified behaviours, spatial use and survivorship, and few studies have investigated the impacts of translocation within a metropolitan area. Aims In the present study, we investigated the impacts of translocation on the most commonly encountered snake in Perth Western Australia, the dugite (Pseudonaja affinis, Elapidae), by comparing the space use of resident and translocated snakes. Methods We captured 10 dugites and attached telemetry packages, composed of a radio-telemetry transmitter and global positioning system (GPS) data-logger, externally to their tails. Snakes were either released within 200 m of their initial capture sites (residents, n = 6) or moved to new unconnected habitat at least 3 km away (translocated, n = 4). Spatial-use data were analysed using general linear models to identify differences between resident and translocated dugites. Key results Translocation influenced space use of dugites and detrimentally affected their survivorship. Translocated snakes had larger activity ranges than did residents, and there was a trend towards travelling greater distances over time. Mortality for all snakes was high: 100% for translocated snakes, and 50% for residents. Conclusions Urban dugites face many threats, and snakes were negatively affected by translocation. The GPS technology we used did not improve the quality of the data over traditional radio-telemetry methods, owing to the cryptic nature of the snakes that spent much of their time under cover or underground. Implications These findings support the growing body of evidence that translocating ‘problem’ snakes is a not a humane method of animal management, and alternatives such as public education, may be more appropriate.