Basking Sites Research Articles

The rocks are hotter on the other side of the fence: roadside habitats should inform mitigation design

Maintaining viable populations of large reptiles is often challenging in road fragmented landscapes. While mitigation structures can reduce impacts, few studies have investigated how mitigation success can be affected by roadside habitats. In southeast Ohio, USA, we evaluated mitigation effectiveness for state-endangered timber rattlesnakes (Crotalus horridus) at a new highway in a forested landscape. Road construction at the study site created a wide corridor of open canopy habitats (the right-of-way; ROW) containing roadcuts and stone piles. However, exclusion fencing was constructed along the forest-ROW boundary, leaving the open canopy habitats on the road-side of the fence. Over three years, we monitored 6 rattlesnakes using radiotelemetry and found that rattlesnakes repeatedly crossed the fence to access forest-edge and ROW habitats. Rattlesnakes ostensibly crossed through damaged sections of the fence. The ROW was used most intensively by gravid females (n = 2), with their core home ranges overlapping the ROW by more than 50 percent. Despite the fence crossings, all home ranges were bounded by the highway and no rattlesnake road mortality was observed. Operative temperature models revealed that the ROW provided warmer thermal regimes that were rare or unavailable in the forest. On average, field preferred gestation temperatures (Tb = 29.7°C, SD = 1.8) could be attained or exceeded for more than 5 times as many hours per day in the ROW (7.8 hours) than in the forest (1.4 hours). Habitat selection models indicated gravid females selected warmer thermal habitats that were spatially concentrated in the ROW and edge habitats, while non-gravid snakes avoided the ROW beyond the forest edge. Habitat use within the ROW was mostly limited to rocky microhabitat structures, especially riprap stone piles and subsurface rock crevices on roadcuts, which provided buffered thermal regimes with refugia from extreme temperatures during the day and warmer Te through the night. In forested landscapes, we encourage road planners to consider whether new road corridors are likely to introduce basking sites, and if so, maintain those features on the habitat-side of exclusion fencing, and consider restoring basking sites in the surrounding forest to reduce the potential for ecological trap formation.

Common lizard microhabitat selection varies by sex, parity mode, and colouration

BackgroundAnimals select and interact with their environment in various ways, including to ensure their physiology is at its optimal capacity, access to prey is possible, and predators can be avoided. Often conflicting, the balance of choices made may vary depending on an individual’s life-history and condition. The common lizard (Zootoca vivipara) has egg-laying and live-bearing lineages and displays a variety of dorsal patterns and colouration. How colouration and reproductive mode affect habitat selection decisions on the landscape is not known. In this study, we first tested if co-occurring male and female viviparous and oviparous common lizards differ in their microhabitat selection. Second, we tested if the dorsal colouration of an individual lizard matched its basking site choice within the microhabitat where it was encountered, which could be related to camouflage and crypsis.ResultsWe found that site use differed from the habitat otherwise available, suggesting lizards actively choose the composition and structure of their microhabitat. Females were found in areas with more wood and less bare ground compared to males; we speculate that this may be for better camouflage and reducing predation risk during pregnancy, when females are less mobile. Microhabitat use also differed by parity mode: viviparous lizards were found in areas with more density of flowering plants, while oviparous lizards were found in areas that were wetter and had more moss. This may relate to differing habitat preferences of viviparous vs. oviparous for clutch lay sites. We found that an individual’s dorsal colouration matched that of the substrate of its basking site. This could indicate that individuals may choose their basking site to optimise camouflage within microhabitat. Further, all individuals were found basking in areas close to cover, which we expect could be used to escape predation.ConclusionsOur study suggests that common lizards may actively choose their microhabitat and basking site, balancing physiological requirements, escape response and camouflage as a tactic for predator avoidance. This varies for parity modes, sexes, and dorsal colourations, suggesting that individual optimisation strategies are influenced by inter-individual variation within populations as well as determined by evolutionary differences associated with life history.

Microhabitat sharing for basking between squamate species in Poland

Aggregations (e.g. group basking) by snakes are usually limited to specific life cycle phases (e.g. mating) or are a consequence of drastic environmental changes (e.g. habitat destruction), high prey densities or highly limited resources within an environment (e.g. basking sites, wintering dens). Here, we report intra- and interspecific observations of four reptile species (primarily Natrix natrix and Vipera berus) sharing basking sites at the confluence of the rivers Dunajec and Poprad near the town of Stary Sącz in southern Poland. From a total of 84 records in the field between 2020–2022, there were 11 interactions from 24 July 2020 to 1 May 2022. Previous studies have indicated direct competition or interference in many species, which we did not observe. There is a noticeable lack of such observations of microhabitat sharing for basking between squamate species in scientific literature. Hence, the accumulation of such observations has the potential to reveal new insights into the behaviour and ecology of N. natrix and V. berus.

Juveniles are different: substrate selection in juvenile green lizards Lacerta bilineata

The relationship between a reptile and its thermal environment is a key feature of habitat use, which may be impacted by, among others, the requirements for food, avoidance of competitors and predators. Juvenile lizards are subject to the same ecological pressures, but may additionally experience predation or exclusion from prime basking site by adults and hence their capacity to achieve preferred body temperatures. In this paper, we examined basking site selection in juvenile western green lizards, Lacerta bilineata and compared them to basking site availability. Secondly, measurements of morning substrate temperatures at different basking sites were compared to basking site selection over the same period. The results indicated that juveniles selected substrates with fast heating surfaces, for example fallen branches for basking, in greater frequency than their availability but in even greater than expected frequency on the cooler surfaces of clusters of bramble plant. This finding contrasted with basking site selection in adult L. bilineata in a previous study where wood surfaces was preferred over non-wood surfaces whilst avoiding basking on bramble. This illustrates the different ecological requirements between adults and juveniles.

Living in Patchy Habitats: Substrate Selection by Basking Sympatric Lizards in Contrasted Anthropogenic Habitats in Western France

The influence of temperature on the physiological processes in reptiles is well known, for example growth, reproduction and muscular energy are all temperature dependent. However, there may be constraints on the ability of a reptile to harness thermal energy, particularly during cold seasons in the temperate zones. Substrate selection is a key factor in enhancing thermoregulation since it can enhance rate of heat uptake. For example, wood substrates are known to increase rates of heat gain in basking reptiles enabling earlier attainment of optimum body temperatures compared to other substrate types, which enables increased time available for other activities. In this paper we describe substrate use for basking in populations of Lacerta bilineata and Podarcis muralis in a hedgerow and a population of Podarcis muralis in a suburban garden in western France. The proportions of substrate used were compared against a null model of substrate availability. When different substrates were pooled based on material similarities both species were recorded in greater frequency on wood based materials in comparison to their availability compared to non-wood substrates. However at a finer level, in comparison to the null model of substrate availability (fallen tree branches, tree stumps, open ground etc), P. muralis showed strong substrate selection whereas L. bilineata did not depart significantly from the null model. We speculate that intra-specific aggression in L. bilineata was one possible cause of this result due to dominant individuals limiting access to prime basking sites in smaller or female lizards. Differences in communal basking between the two species supported this notion.

Status and distribution of Mugger Crocodile Crocodylus palustris in the southern stretch of river Cauvery in Melagiris, India

A study was conducted to examine the population estimate and spatial distribution of Mugger Crocodile in the southern stretch of river Cauvery, Hosur Forest Division from February 2019 to May 2019. In total, 53 basking sites and 45 Muggers were encountered by direct sighting in the 24-km river stretch using daytime ground based survey approach. N-mixture models estimated an average Mugger density of 2.05 individuals per kilometre for daytime survey. A night spotlight survey across the seven segments of river stretch was also conducted which yielded direct sightings of 54 Muggers with an average encounter rate of 2.25 individuals per kilometre. Two crocodile nests with hatched egg shells were also observed on the sand banks of the river. We concluded that a potential healthy and breeding population of Mugger inhabits the studied stretch of the river. Multiple corresponding analysis was also performed, which demonstrated that Mugger responds to sandy banks alongside deep water pools for basking in contrast to river segments with shallow depth and dense riparian cover.

A creeping threat? Introduced Macquarie turtles and the future of endangered helmeted turtles in southern Australia

Abstract The introduction of freshwater turtle species outside their natural ranges may threaten native turtles through competition for resources such as food or basking sites, hybridization, and transmission of diseases or parasites. The three southern species of Australian helmeted turtles (Myuchelys bellii, Myuchelys georgesi, and Myuchelys purvisi) had no or minimal distributional overlap with the widespread Australian Macquarie turtle, Emydura macquarii, until about 30 years ago. Since that time, E. macquarii has been introduced within the ranges of all three Myuchelys spp., possibly through the release or escape of pet turtles. The occurrence, catch per unit effort, and population structure of E. macquarii were compared among four introduced populations within the ranges of southern Myuchelys spp. and four native populations. The aim was to provide insight into the status of the introduced populations, their likely current impact on Myuchelys spp., and their potential for future increase. Data analysis suggested that the introduced populations of E. macquarii are at varying stages of the invasion process and not yet severe threats to Myuchelys spp. However, continuing proliferation of introduced E. macquarii is likely, potentially placing intensifying pressure on Myuchelys populations in the long term. Research is needed on interactions of E. macquarii and Myuchelys spp. and their comparative competitive abilities in order to inform the difficult policy decision of whether invasive E. macquarii should be removed or controlled.

Basking Site Selection and Usage Strategies of the European Pond Turtle, <i>Emys orbicularis</i> (Linnaeus, 1758) in Babat valley (Gödöllő, Hungary)

Sun basking is the most common method for freshwater turtles, such as the European pond turtle, to maintain optimal body temperature. The attributes of the macro- and microhabitat features around the basking sites affect the basking site selection of the European pond turtle. To protect the European pond turtle, it is important to know the basking habits among the biological characteristics of the species, along with the effects of the habitat characteristics and the choice of the type of basking sites. The purpose of our research was to detect the effects of macro- and microhabitat features on the selection of basking sites. We wanted to determine basking site type selection according to the carapace length classes and if there is any difference in the choice of basking trunks and branches with different thicknesses. Turtles choose basking sites with less closed vegetation in their environment. We have detected seasonal differences in the microhabitat features. The closing reed and Typha sp. had a negative effect on the number of observed basking turtles. The most popular type of basking sites in the pond system was the commonly occurred fallen tree trunks and branches in the water, regardless of turtle body size. Most turtles used thinner tree trunks and branches for basking. In the meantime, we found differences in the choice of basking trunks between the turtles with different body sizes. Younger turtles with smaller bodies appeared in larger numbers on emergent branches with smaller diameters.

Basking and retreat site selection of Phymaturus palluma, a rock-dwelling lizard in the Highlands of Aconcagua.

Basking and retreat sites constitute a key resource in the habitat of any ectotherm. Identifying the elements that are used and modelling the microhabitat selection of species is crucial for assessing the impact of anthropogenic disturbances at the population level and, therefore, focusing on conservation efforts. We investigated how structural attributes of the microhabitat and biotic factors influence the probability of basking and retreat sites use by Phymaturus palluma, a rock-dwelling and viviparous lizard endemic to the Central Andes of Argentina. We measured the characteristics of a series of rocks (basking sites) and shelters (retreat sites) in the study area and compared lizard resource use versus availability using resource selection analyses (RSFs). According to our best RSF model, P. palluma select high and large rocks as basking sites and prefer those near their retreat sites and far from the basking sites of their neighbours. In contrast, retreat site selection is related to the length, depth, slope, and width of the shelter. Microhabitat site selection of P. palluma is associated with behavioural improvements such as enhancing basking capacity, reducing both intraspecific competition with neighbours and predation risk.

Observations on the Short-Term Effects of Motorboat Disturbance on the Use of Basking Sites by Female Northern Map Turtles

We observed the number of basking female Graptemys geographica (northern map turtles) at 4 basking sites before and after controlled motorboat disturbances using time-lapse cameras. In the 6 hrs following disturbance, the mean number of turtles basking at a site was 43.8% less than before the disturbance; this reduction in use of basking sites suggests that a single boat disturbance event can markedly affect the use of basking sites by female turtles for several hours. The behavioral and physiological impacts of such a shift in habitat use are unclear and should be the focus of future studies.

Tree Removal Likely Improves Thermal Quality of Basking Sites for an Imperiled Timber Rattlesnake Population at the Northern Edge of Its Range

Lack of natural disturbance in many forests in northeastern North America has resulted in increased canopy cover and a reduction of open-habitat patches. Crotalus horridus (Timber Rattlesnake) in this region depends upon open basking and gestation sites, and its populations have declined markedly. We evaluated the utility of mechanical tree removal to restore potential basking habitat for a highly imperiled Timber Rattlesnake population in New Hampshire. We used a before–after, control–impact study to test for the effects of tree removal on environmental temperature and Timber Rattlesnake and other wildlife use of 3 potential basking sites. Mean temperatures were significantly higher and more variable post-treatment, while minimum temperatures were relatively unaffected. The number of temperature readings within the span of selected body temperatures of gravid female Timber Rattlesnakes (25.2–31.7 °C) increased post-treatment. Using time-lapse cameras, we detected rattlesnakes during 5 days at post-treatment sites but on only 1 day at a control site. Detections of potential rattlesnake prey species did not change following treatment, and few potential rattlesnake predators were detected pre- or post-treatment. Our results suggest that tree removal around potential basking sites likely improves thermal habitat quality for Timber Rattlesnakes.

Preliminary data on an affordable UAV system to survey for freshwater turtles: advantages and disadvantages of low-cost drones

Unmanned aerial vehicles (UAVs) are established, valuable tools for wildlife surveys in marine and terrestrial environments; however, they are seldom utilized in freshwater ecosystems. Therefore, baseline data on the use of UAVs in lotic environments are needed that balances flight parameters (e.g., altitude and noise level) with image quality, while minimizing disturbance to individuals. Moreover, the traditional high-cost UAVs may present challenges to researchers conducting rapid assessments on species presence with limited funding. However, emerging, affordable UAV systems can provide this preliminary data to researchers, albeit with caveats on reliability of data. We tested a low-cost UAV system to document freshwater turtle presence, species distribution, and habitat use in a small North Carolina wetland. We observed minimal instances of turtles fleeing basking sites (∼0.7%), as this UAV system was only ∼2.1 dB above ambient noise levels at an altitude of 20 m. Freshwater turtles were found primarily in algal mat basking habitats with highly variable numbers observed across locations and flights, likely due to image quality reliability and altitude. Our affordable UAV system was successful in providing baseline information on species presence, size distribution, and habitat preference of turtles in freshwater ecosystems.

Assessment of sand quality of nesting and basking sites of crocodile and turtles in the Chambal River, India

Sand banks are very much useful for the aquatic animals for nesting and basking specially in crocodile and turtles. Being aquatic animals the reptiles in the river such as Gharial, mugger and freshwater turtles come out on the sand bank for basking and laying eggs specially constructed by individual female. The Physico-chemical characteristic of 20 nesting and basking sites of crocodiles and turtles in the Chambal River were carried out between Pali-Chakar nagar riverine stretch, approx. 425 kms during nesting season April, 2006. The sand quality parameters namely average temperature (29.2 0C), average moisture content (8%), average pH (7.5), average electric conductivity (1.3 u mho/cm), average available nitrogen (93.7 Kg/h.), average available phosphorous (3.8 Kg/h.) and average potash (416.6 Kg/h.), were analysed reflects on the pristine nature of the river in Chambal. The sand quality analysis indicated that the river sand in the River area is pollution free and can serve as a good habitat for many aquatic animals including reptilian species.

Non-random perch selection by cryptic lizards, Amphibolurus muricatus

Many animals make use of camouflage to avoid or reduce visual detection by predators or prey species. Among the diverse forms of animal camouflage, background matching—where an individual’s appearance helps it blend into the visual backdrop of a scene—is commonly observed as a major function of cryptic species’ patterning and coloration. While some animals can rapidly modify their pattern to match their surroundings and better avoid detection, most possess static patterns or coloration and cannot quickly adjust to suit the visual environment. We expect such animals to consider the cryptic suitability of a background they choose to occupy, ideally selecting one with features suitable relative to their own markings, thereby maximizing concealment. This relationship is complicated by the potential range of different substrates typically available in any one habitat, as conspicuousness may vary considerably when viewed against the different background options available. In the present study, we tested some of these assumptions, investigating whether cryptic lizards, Amphibolurus muricatus (jacky dragons), utilized perch options with features complementary to their dorsal camouflage patterns more so than unsuitable perches. In two experiments, lizards were provided with perch options differing in coloration and cover availability and pattern, respectively. Individuals spent significantly more time using perches with cover available in the first experiment, and those with more complex patterns in the second. These findings suggest cryptic lizards may be selecting basking sites in a non-random fashion with respect to the visual environment in order to enhance camouflage success and that cover may be more important to perch selection than previously thought. SIGNIFICANCE STATEMENT: Among animals that employ visual camouflage as a primary survival strategy, differences in conspicuousness caused by being viewed upon the various suitable and unsuitable backgrounds available in a habitat have the potential to drastically affect prey capture and predation, and hence survival. With respect to this, cryptic animals should prefer to occupy substrates that are relevant to their own patterns and offer better concealment. Research in this behavioral maintenance of camouflage has focused on spectral properties of camouflage and substrates, but studies on fine-scale pattern and behavior in camouflage are under-represented. In captive perch choice experiments, we found that male jacky dragons (Amphibolurus muricatus) preferred perches with more complex patterns and those with plant cover available nearby. This research highlights the important role of behavior in supporting camouflage strategies and some of the considerations made when cryptic individuals choose substrates.

Impact of human disturbance on the thermoregulatory behaviour of the endangered ringed sawback turtle (Graptemys oculifera)

Abstract Human recreational disturbance of riverine environments may be contributing to population declines of aquatic organisms worldwide. Aquatic turtles that are heavily dependent on basking in sunlight to maintain an optimal body temperature may abandon basking perches because they perceive humans as potential predators. The impact of boat traffic, the availability of basking structures, and various environmental factors on the basking behaviour of the ringed sawback turtle (Graptemys oculifera) was assessed at two sites on the Pearl River, Mississippi, USA. This information was used to model the likely effects of human disturbance on the body temperature of large female turtles. Both the duration of basking and the percentage of turtles in a basking group that abandoned their basking perch were influenced by the availability of alternative basking sites, frequency of boat traffic, boat speed enforcement zones (‘wake’ or ‘no wake’), boat type, air temperature, weather conditions, and Julian day. A simulation model of anthropogenically disturbed and undisturbed adult female ringed sawbacks showed that disturbance probably decreases the mean daily body temperature, especially at higher disturbance probabilities and in May, when the air temperature is low. Management recommendations are provided that minimize the adverse effects of unintentional human disturbance of the ringed sawback to enable more effective conservation of this endangered, endemic species. Such methods are likely to be useful elsewhere as recreational disturbance becomes a greater conservation issue worldwide.

Spatio‐temporal partitioning between two sympatric crocodilians (Gavialis gangeticus & Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India

Abstract Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.

The impact of posture and basking orientation on thermoregulation in the Sungazer (Smaug giganteus)

Body temperature (Tb) is one of the most influential factors affecting physiological processes in ectothermic animals. Reptiles use behaviours such as shuttling, and postural and orientation adjustments to ensure that Tb remains close to a target. It is thought that target body temperature (Ttarget) is aligned to the physiological and behavioural thermal optima of the animal. The Sungazer (Smaug giganteus), a Threatened lizard species, is unique amongst the Cordylidae in that lizards inhabit self-excavated burrows in open grasslands, a habitat in which there are few exposed rock basking sites. In this situation, Tbs are likely to be greatly influenced by postural and orientation adjustments during basking. We measured Tbs using modified iButtons, and calculated Ttarget of free-ranging Sungazers in order to assess the impact of body posture and orientation in the thermoregulation of the species. We used camera traps to record lizard behaviour at burrow entrances and aligned these measures to measures of Tb. Ttarget was 30 ± 1.4 °C, and Tbs remained within this range for 371 ± 162 min per day. The anterior body-up postures resulted in faster heating and higher Tbs. Lizards heated faster when facing away from the sun and spent proportionally more time in this orientation in the morning when Tbs were lower than Ttarget. Our findings suggest that their wide behavioural repertoire allows Sungazers to thermoregulate effectively over a broad range of environmental conditions and may thus be able to effectively respond to changing climatic conditions.

Context-dependent behavioural lateralization in the European pond turtle, Emys orbicularis (Testudines, Emydidae).

Lateralization presents clear advantages in ecological contexts as the dominance of one brain side prevents the simultaneous activation of contrasting responses in organisms with laterally located eyes. This is crucial in selecting a safe refuge during a predatory attack and may strongly affect predator-prey interactions. We explored the possible presence of lateralization in the anti-predatory behaviour of European pond turtles, considering their escape facing a possible predatory attack. Thirty individuals (17 males, 13 females) were exposed to three different environmental situations of gradually increasing predatory threat: escape underwater from an unsafe shelter, diving into the water from a basking site and righting after being overturned. All turtles were tested 20 times for each of the three experiments (60 trials per individual; 1800 overall trials). We recorded multiple behavioural responses in the general context of predation risk. This was done in order to assess both the existence of lateralization and possible correlations among different behaviours as function of lateralization. The number of significant responses to the left side was always prevalent in each of the three simulated anti-predatory situations, suggesting the existence of a lateralized behaviour in this species. At the individual level, the differences we found in the three experiments could be related to different ecological contexts and consequent risk of predation. Our findings, among the few on chelonians, support the possible involvement of right hemisphere activity and, most importantly, reveal how the complexity of a general predatory context can affect the laterality of escape behaviour.

Status of the Nile crocodile population in Pongolapoort Dam after river impoundment

The major Nile crocodile Crocodylus niloticus populations in South Africa are threatened by pollution, habitat alteration/destruction, and poaching. This has highlighted the importance of other minor populations. The Phongola River Nile crocodile population was previously considered as unsubstantial. Consequently, we investigated the Nile crocodile population numbers and status and the effects of the impoundment of the Phongola River on this. In 2009–2010 we determined a minimum population number of 281 Nile crocodiles in Pongolapoort Dam using a combination of survey methods. The population structure was identified as having a minimum of 116 (41.3%) juveniles (<1.2 m total length), 31 (11.0%) subadults (1.2–2.5 m total length) and 134 (47.7%) adults (>2.5 m total length). At the commencement of the breeding season in August, crocodiles congregated at a major basking site where the main tributary entered the dam. Three major nesting areas were identified, two of which were located on the river inlet to the dam. We identified approximately 30 nesting females during the 2009/10 nesting season. Several nests were predated by the Nile monitor Varanus niloticus. There was a total recruitment failure of nests along the river inlet to the dam due to a flash flood of the Phongola River in January 2010. This preliminary study suggests that the Pongolapoort Dam Nile crocodile population has a relatively high potential reproductive output, although their annual successes may vary greatly because of loss of nesting sites as a result of water-level fluctuations and predation. It appears that the river impoundment has generally had a positive impact on this Nile crocodile population, although suitable nesting sites may become limited. Continued long-term monitoring of the Nile crocodile population in Pongolapoort Dam is required to determine if the impoundment continues to support a viable population.

Quantifying predation pressure and the protective role of sheltered basking sites for small snakes in South Africa

Small snakes are frequent prey of predatory birds, reptiles, and mammals. The resulting mortality rate is difficult to quantify given the low likelihood of observing such predation events. However, studies using plasticine snake models have shown that small snakes may experience relatively high rates of predation. Model snakes constructed from slow-drying clay (as a substitute to plasticine) were used to assess the predation rate on small snakes in the Eastern Cape of South Africa. The model snakes were used to test whether snakes basking in semi-shaded positions, with at least half of the body covered by overhanging vegetation are detected by bird and mammal predators. There were relatively high rates of predation, with half of the unconcealed snake models experiencing attacks. The predation rate on partially concealed models is lower than on unconcealed models, but the difference is not statistically significant. Thus, basking in sheltered areas may offer snakes protection against predators; however, predation attempts on concealed models suggests that predators actively seek out areas where prey might hide. This is the first quantification of predation on small snakes in South Africa, and the results generate numerous questions relating to the behavioral ecology of the diverse snake fauna found in this country