Tail Breaks Research Articles

Effect of prey availability on growth-rate trajectories of an aquatic predator, the viperine snake Natrix maura

The energy gained by an organism is used for maintenance, growth and reproduction. In habitats with limited resources, these processes compete for available energy and may induce intraspecific variation in body condition, growth trajectories and reproductive output. We tested the hypothesis that populations exposed to higher food availability are able to grow faster, and attain larger body sizes in the viperine snake (Natrix maura). We estimated snake age by counting growth lines in the skull’s ectopterygoid bone, and compared body size growth curves from three Iberian populations exposed to temporal variation of food resources availability. In the three localities, and in males and females, the growth curves followed a quadratic function that tended to an asymptotic value as growth slowed down. Growth curves showed slower growth rates and an early asymptote for males, in agreement with the reverse sexual dimorphism in body size of this species. We also detected interpopulational differences, with the Ebro Delta population exhibiting slower growth rates and smaller asymptotic body size in both sexes. This population inhabits rice fields with an artificial waterflow cycle, a condition that implies a shorter period of prey availability for snakes, compared to the other two populations, where prey is available for longer periods of time. Moreover, high proportion of snakes with tail breakage in this population indicated high predation pressure. These environmental conditions suggest that food availability and predation pressure may be concurrently acting to produce smaller N. maura at the Ebro Delta than at the other two populations.

Pseudoautotomy inDendrophidion dendrophisandMastigodryas bifossatus(Serpentes: Colubridae): Tail Morphology and Breakage Frequency

The micro and macro structures of the caudal vertebrae and muscles of Dendrophidion dendrophis and Mastigodryas bifossatus were described using histological slides, dissections, radiographs, and clearing and double staining of intact, broken, and healed tails. To analyze the relationship among the frequencies of healed tails we established two populations of D. dendrophis and six groups of M. bifossatus. We found that fractures of the tail in the two species are intervertebral, and there are no morphological and/or structural mechanisms that facilitate the urotomy, which is classified as non-specialized pseudoautotomy. The caudal vertebrae of D. dendrophis and M. bifossatus show minor differences in the shape of the condyle, cotyle, and border of the neural spine, and in the size and orientation of the hemapophysis and pleurapophysis. The absence of bleeding at the moment of tail breakage may indicate the presence of sphincters in the veins and arteries of D. dendrophis. The distal part of the last vertebrae retained in healed tails of D. dendrophis and M. bifossatus participates in the healing processes as a possible source of calcium in the formation of a calcified cap. We found high frequency of tail breakage in both species, which occurs in almost the entire length of the tail, with no specific areas of concentration. There was no difference in the frequencies of healed tails among males and females of different populations of D. dendrophis and M. bifossatus. Juveniles have lower breakage frequencies than adults in both species, except for populations of M. bifossatus from the Cerrado and Pampa.

Tail-breakage effects on snake-body condition

Tail breakage can help reptiles to escape from predators. Despite the immediate advantage for survival, tail loss can also entail negative consequences. We have examined some potential costs associated to tail breakage in the colubrid snake Rhinechis scalaris (Schinz, 1822), a medium-sized terrestrial species with a high incidence of tail breakage (40.7% in the largest individuals). Tail damaged individuals were not smaller than undamaged individuals, fat-body levels (a measure of body condition) did not differ between tail damaged and tail undamaged individuals, and no relationship was found between the remaining pairs of subcaudal scales (a measure of tail-loss severity) and fatbody level in specimens with damaged tails. All results failed to support a cost in terms of overall body condition associated with tail breakage. The tail is of low importance for locomotion, there are no vital morphological structures in the tail necessary for a healthy physiology, and snakes undergo non regenerative tail loss.

Tail loss affects fecundity but not offspring traits in the Chinese skink Eumeces chinensis

Abstract We used the Chinese skink Eumeces chinensis as a model animal to study the effects of tail loss on reproductive investment and offspring traits. A total of 147 wild-captured adult females were divided into four groups according to their tail conditions. Tail breaks occurred most frequently in the proximal portion of the tail and least frequently in the distal portion, with the middle portion in between. This finding suggests that tail breaks occurring in nature often entails substantial energetic costs in E. chinensis where the tail is a major site of energy storage. The proportion of females that laid eggs was higher in females with intact or completely regenerated tails than in those with broken tails. Following whole-tail autotomy, the clutch size was reduced by 17%, and the clutch mass was reduced by 14%. Females undergoing substantial tail autotomy reduced reproductive investment, and they did so by reducing the number but not the size of eggs produced. None of the egg and hatchling traits was affected by tail loss. Comparing our data with those reported for other oviparous and viviparous skinks allows us to draw two general conclusions: one is that fecundity (clutch or litter size) is affected by tail loss in all species so far studied, whereas offspring size is affected by tail loss in some species, but not in others; the other is that the reduction in fecundity following tail loss is more evident in species lacking abdominal fat bodies [Current Zoology 58 (2): 228–235, 2012].

Do invasive rodents impact endangered insular iguana populations?

Ample evidence confirms that large invasive mammalian competitors and predators can devastate endangered insular iguana populations. However, the impact of invasive rodents, particularly rats (Rattus rattus), has remained elusive. Tail autotomy occurs frequently in lizards, often as an antipredator tactic, but sometimes from intraspecific aggression. Tail autotomy can incur substantial locomotor, behavioral, energetic, and survival costs. Furcation (i.e., dividing into branches) of regenerated tails may also result from attempted predation but occurs much more rarely, and with unknown costs. To evaluate the potential impact of invasive rodents—primarily rats—on West Indian rock iguanas (genus Cyclura), we compared tail-break and tail-furcation frequencies among 19 insular iguana populations (3,537 individuals) representing three species in the Bahamian Archipelago (including the Turks and Caicos Islands). The findings supported our three hypotheses: (1) that tail-break and tail-furcation frequencies are significantly higher in populations coexisting with invasive rodents; (2) that tail-furcation results primarily from failed predation attempts rather than intraspecific aggression; and (3) that frequencies of tail breaks and tail furcation are associated with each other, suggesting a degree of commonality in cause-effect (i.e., failed predation attempts). Tail furcation, in contrast to tail breakage, never occurred on islands lacking invasive mammalian predators. We conclude that invasive rodents, particularly rats, may have a greater impact on endangered insular iguana species than previously recognized.

Large eddy simulation of the unsteady flow-field in an idealized human mouth–throat configuration

The present study concerns the simulation and analysis of the flow field in the upper human respiratory system in order to gain an improved understanding of the complex flow field with respect to the process affecting drug delivery for medical treatment of the human air system. For this purpose, large eddy simulation (LES) is chosen because of its powerful performance in the transitional range of laminar and turbulent flow fields. The average gas velocity in a constricted tube is compared with experimental data ( Ahmed and Giddens, 1983) and numerical data from Reynolds-averaged Navier–Stokes (RANS) equations coupled with low Reynolds number (LRN) κ–ω model ( Zhang and Kleinstreuer, 2003) and LRN shear–stress transport κ– ω model ( Jayaraju et al., 2007), for model validation. The present study emphasizes on the instantaneous flow field, where the simulations capture different scales of secondary vortices in different flow zones including recirculation zones, the laryngeal jet zone, the mixing zone, and the wall shear layer. It is observed that the laryngeal jet tail breaks up, and the unsteady motion of laryngeal jet is coupled with the unsteady distribution of secondary vortices in the jet boundary. The present results show that it is essential to study the unsteady flow field since it strongly affects the particle flow in the human upper respiratory system associated with drug delivery for medical treatment.

Bias in bacteriophage morphological classification by transmission electron microscopy due to breakage or loss of tail structures

Virtually every study that has used transmission electron microscopy (TEM) to estimate viral diversity has acknowledged that loss of phage tails during sample preparation may have biased the results. However, the magnitude of this potential bias has yet to be constrained. To characterize biases in virus morphological diversity due to tail loss, six phage strains representing the order Caudovirales were inoculated into sterile sediments and soils. Phage particles were then extracted using standard methods. Morphologies of extracted phage particles were compared to those of unmanipulated control samples to determine the extent of tail breakage incurred by extraction procedures. Podoviruses exhibited the smallest frequency of tail loss during extraction (1.2-14%), myoviruses were moderately susceptible to tail breakage (15-40%), and siphoviruses were highly susceptible (32-76%). Thus, TEM assessments of viral diversity in soils or sediments by distribution of tail morphologies may be biased toward podoviruses and virions lacking tails, while simultaneously underestimating the abundance of siphoviruses. However, since the majority of viral capsids observed under TEM were intact, estimates of viral diversity based on the distribution of capsid diameters may provide a more reliable basis for morphological comparisons within and across ecosystems.

Tail breakage frequency as an indicator of predation risk for the aquatic snake Natrix maura

AbstractIt is difficult to measure predation risk for secretive animals such as snakes. The frequency of tail breakage has been suggested as a parameter for measuring predation risk in these reptiles. Consequently, we hypothesise that tail breakage frequency is expected to vary intraspecifically between populations submitted to different numbers of predators, probably, to different predation risk. The colubrid snake Natrix maura has adapted to living on fish farms, which are protected from aerial predators by wire mesh, so that these farms provide researchers with a predator-exclusion scenario. We measured tail breakage frequency in this snake on a fish farm and compared the results with data from three populations in natural settings in the Iberian Peninsula under assumed higher predation risk from a complete community of predators. A logistic regression analysis demonstrated that snake body size and predator exclusion affected the probability of tail breakage, while sex had no effect. We found an ontogenetic increase in the frequency of tail breakage, a general pattern in snakes and, notably, marked differences between populations according to predation risk: snakes from the fish farm showed a low frequency of tail breakage (5.1%), whereas snakes from natural habitats, with five-fold more potential predators on average, demonstrated a higher frequency of tail breakage (18.7%). We conclude that tail breakage frequency is a reliable indicator of predation risk in this aquatic snake.

Patterns of tail breakage in the ladder snake ( Rhinechis scalaris) reflect differential predation pressure according to body size

Predator–prey interactions are key factors in the evolution of defensive tactics. In snakes, shy organisms from which direct evidence of predator–prey interactions is difficult to obtain, injuries are potential indicators of both the nature and frequency of interactions. We studied the incidence of tail breakage and body scarring in the ladder snake, Rhinechis scalaris, an actively foraging Mediterranean snake, and tested several hypotheses that link body injuries and snake life-history traits, mainly under sexual and ontogenetic aspects. Evidence is presented supporting an ontogenetic shift in the frequency of tail breakage, with the incidence of tail loss increasing as a logistic function of snake size. We relate this finding to the adaptive significance of ontogenetic shifts in dorsal pattern and the reaction of snakes to approaching predators; small individuals are more likely to remain immobile than are medium to large individuals, the former aided by a concealing dorsal pattern with transverse lines, and the latter by a striped pattern. This species exhibited sex differences in body scarring but not in tail breakage, nor did we encounter evidence to suggest that snakes experience multiple tail breaks over time, thus failing to support the sexual difference and multiple tail breakage hypotheses. Moreover, we failed to find a lower frequency of body scarring than tail breakage; hence, our results do not afford evidence that frequency of tail breakage represents an inefficiency of predators in catching or dispatching ophidian prey.

Open Geospace General Circulation Model simulation of a substorm: Axial tail instability and ballooning mode preceding substorm onset

Recent global simulations of substorms show that before the onset of near‐Earth reconnection the pressure equilibrium in the tail breaks down. This instability has no cross‐tail variation and is thus not a ballooning mode, and it is also distinct from the tearing mode. Here, we analyze an Open Geospace General Circulation Model simulation run of the 23 March 2007 substorm and find the same instability. Because this mode has no significant cross‐tail variation associated with it we call it the KY0 mode. Besides the KY0 mode we also find the classical ballooning mode in the simulation. It has a wavelength of ∼0.5 RE and is marginally, but sufficiently, resolved as shown by a higher‐resolution control run. These results suggest a new scenario for the substorm expansion phase onset. During the growth phase magnetic flux is added to the lobes and the plasma sheet thins but remains in equilibrium. When force balance is no longer possible the KY0 instability grows and accelerates plasma tailward. The divergence of the resulting tailward flow reduces the normal magnetic field and thereby makes the current sheet tearing unstable. The tearing mode grows right out of the KY0 mode. The classical ballooning mode grows at the same time and is superimposed on the KY0 mode, but its role in initiating reconnection is still unclear. The growth time of the KY0 mode, ∼2 min, is both consistent with the notion of an explosive growth phase and with recent ground‐based observation of the initial growth of auroral arcs before auroral breakup.

ALTERNATIVE MATING STRATEGIES AND THE EVOLUTION OF SEXUAL SIZE DIMORPHISM IN THE SIDE-BLOTCHED LIZARD,UTA STANSBURIANA: A POPULATION-LEVEL COMPARATIVE ANALYSIS

Population-level comparative analyses can link microevolutionary processes within populations to macroevolutionary patterns of diversification. We used the comparative method to study the evolution of sexual size dimorphism (SSD) among populations of side-blotched lizards (Uta stansburiana). Uta stansburiana is polymorphic for different male mating and female life-history strategies in some populations, but monomorphic in others. We tested whether intrasexual selection among males, fecundity selection on females, and the presence of polymorphic strategies affected levels of SSD. We first resolved a phylogeny for 41 populations across the range of the species and documented a substantial regional structure. Our intraspecific data had significant phylogenetic signal, and correcting for phylogeny using independent contrasts had large effects on our results. Polymorphic populations had male-biased SSD and changes in male body size, levels of tail breaks, and SSD consistent with the intrasexual selection hypothesis. Monomorphic populations had changes in female size, clutch size, and SSD consistent with the fecundity selection hypothesis. Fecundity selection is a likely cause of some monomorphic populations having no SSD or female-biased SSD. Our results suggest that changes in mating strategies are associated with phenotypic diversification and multiple evolutionary forces can shape SSD.

Different habitats, different pressures? Analysis of escape behaviour and ectoparasite load in Podarcis sicula (Lacertidae) populations in different agricultural habitats

AbstractHuman agricultural activities can deeply alter the environment thus provoking major impacts on a variety of organisms. Agricultural habitats however can be very different from one another in terms of habitat structure and management intensity, presenting varying pressures and/or benefits for different species. Agro-ecosystems can have opposing effects on reptiles and in some circumstances the presence of a species can even been enhanced by agricultural practices. We focused our study on Podarcis sicula, a relatively widespread lacertid lizard commonly present in agro-environments in Italy. We examined escape behaviour, caudal autotomy rates and ectoparasite load (tick infestation) in populations living in two different land uses, olive tree plantations and vineyards. All three aspects seemed to be deeply influenced by habitat structure. Predation pressure, as evaluated by tail break frequency, was lower in olive tree plantations, the most structurally complex habitats. In this type of habitat lizard escape behaviour was characterised by a clear preference for olive trees as refuges: individuals ran farther distances on average to reach the trees and hid inside them for a relatively long time. In vineyards, on the contrary, a less clear escape strategy was observed, showing a use of more temporary refuges. Also tick (Ixodes ricinus) infestation differed among land uses, being higher in olive tree plantations, probably in relation to vegetation cover features. Differences were found also between managements (with a higher tick load in traditional cultivations) and sexes, with males being more parasitized.

To cut a long tail short: a review of lizard caudal autotomy studies carried out over the last 20 years

AbstractCaudal autotomy, the ability to shed the tail, is common in lizards as a response to attempted predation. Since Arnold's substantial review of caudal autotomy as a defence in reptiles 20 years ago, our understanding of the costs associated with tail loss has increased dramatically. In this paper, we review the incidence of caudal autotomy among lizards (Reptilia Sauria) with particular reference to questions posed by Arnold. We examine tail break frequencies and factors that determine occurrence of autotomy in natural populations (including anatomical mechanisms, predation efficiency and intensity, microhabitat preference, sex and ontogenetic differences, as well as intraspecific aggression). We also summarize the costs associated with tail loss in terms of survivorship and reproduction, focusing on potential mechanisms that influence fitness (i.e. locomotion costs, behavioural responses and metabolic costs). Finally, we examine the factors that may influence the facility with which autotomy takes place, including regeneration rate, body form and adaptive behaviour. Taking Arnold's example, we conclude with proposals for future research.

Many‐lined sun skinks (Mabuya multifasciata) do not compensate for the costs of tail loss by increasing feeding rate or digestive efficiency

We used the many-lined sun skink (Mabuya multifasciata) as a model system to evaluate the energetic and locomotor costs of tail loss, and to examine whether tailless skinks compensate for the costs of tail loss by increasing feeding rate or digestive efficiency. We successively removed three tail segments from each of the 20 experimental skinks initially having intact tails. Energy content in each removed tail segment was measured, and swimming performance was measured for each experimental skink before and after each tail-removing treatment. Another independent sample of 19 skinks with intact tails were measured for swimming performance to serve as controls for successive measurements taken for the experimental skinks. Tailless experimental skinks and control skinks were then measured for food intake and digestive efficiency. Tail loss affected swimming speed, but the adverse influence was not significant until more than 55% of the tail (in length) was lost. Our data show that partial tail loss may not severely affect energy stores or locomotor performance in M. multifasciata. However, as tail breaks occurred more frequently in the proximal portion of the tail in skinks collected from the field, we conclude that caudal autotomy occurring in nature often incurs substantial energetic and locomotor costs. As tailless and tailed skinks did not differ in food intake, apparent digestive coefficient and assimilation efficiency, we conclude that tailless individuals do not compensate for the costs of tail loss by increasing feeding rate or digestive efficiency in M. multifasciata.

Breakup of the tail of a bubble in a non-Newtonian fluid

. First, a wide shot of abubble is presented left . Then, a zoom of three differenttails is shown. In the first case, the cusp is axisymmetric.Increasing the volume, the cusp becomes asymmetric with a“knife-edge” shape. In the third case, the tail breaks in a “fishbackbone” pattern. In Fig. 2, sequences of images for vol-umes of 523, 718, and 955 mm

Morphological, functional and evolutionary aspects of tail autotomy and regeneration in the ‘living fossil’Sphenodon (Reptilia: Rhynchocephalia)

Tail autotomy and regeneration are less known in Sphenodon (‘Reptilia’: Rhynchocephalia) than in Squamata. We examined museum specimens, Sphenodon guntheri (N = 8) and Sphenodon punctatus (N = 172), wild Sphenodon punctatus (N = 19) and Sphenodon sp. skeletons (N = 8). In S. punctatus, unlike in typical Squamata, sexes had similar relative (intact) tail lengths, and regeneration frequencies; tail and body growth was isometric. Tail breakage was usually intravertebral, usually followed by ablation of a variably sized terminal vertebral piece, partly deviating from lizards. Hypothetically, imperfect autotomy results from sphenodon's primitiveness. As in squamates, tail-losers were morphologically more left-side dominant than tail-retainers. Individual directional asymmetries in digit morphology and in digit injury were correlated (in lizards observed only at population level); tail-losers had more fluctuating asymmetry but their exclusion did not facilitate morphological taxonomic distinctions (no ‘Seligmann effect’). In S. punctatus, extents and directions of sexual dimorphism paralleled differences between tail-retainers and tail-losers, females resembling tail-losers, also accounting for character interdependence (developmental constraints; employing a method similar to phylogenetic contrasts). The variation in the location of tail injury was correlated with the continuum of variation between injured and intact (pholidotic) morphotypes. These last two phenomena remain to be explored in Squamates. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 721–743.

DEFENSIVE BEHAVIOR OF THE LIZARD TROPIDURUS MONTANUS (TROPIDURIDAE): EFFECTS OF SEX, BODY SIZE AND SOCIAL CONTEXT

Abstract The defensive behavior of the endemic tropidurid lizard Tropidurus montanus was studied from January to March 2004 at the Serra do Cipo, State of Minas Gerais, southeastern Brazil. This lizards relied on crypsis associated with immobility as the primary strategy of defense to avoid predators. When attacked, locomotor escape was the tactic employed by all recorded individuals. We analyzed the effects of sex on the maximum flight distance and the effects of body size and social context on maximum flight distance and time of flight for males. Males and females did not differ in maximum flight distance. Males with or without a nearby neighbor did not differ in maximum flight distance, but males close to neighbors increased time spent in flight. We found no effect of male body size on maximum flight distance or on the duration of flight. During capture, lizards exhibited threat display, bite, tail waving, tail breakage, thanatosis, forced freeing, body inflation, and cloacal discharge.

MORPHOLOGY, REPRODUCTIVE BIOLOGY AND DIET OF DENDROPHIDION DENDROPHIS (SCHLEGEL, 1837) (SERPENTES, COLUBRIDAE) IN BRAZILIAN AMAZON

Reproductive (sexual dimorphism, reproductive maturity, reproductive cycle, recruitment and fecundity), feeding biology (diet composition and frequency of food items) and morphology data (body size and tail breakage) of Dendrophidion dendrophis are presented, based on the analysis of 95 specimens (61 males and 34 females) from different regions of Brazilian Amazon. There were no significant differences in the snout-vent length and tail length between males and females. Males reach reproductive maturity with a smaller snout-vent length than females, which become sexually mature when they reach approximately three times the size of the newborns. A positive, yet only slightly significant, relationship was observed between the number of vitellogenic follicles and eggs and the snout-vent length of the females. Reproductive activity occurs throughout the year, suggesting aseasonal breeding for the species. The high incidence of broken tail or visible rupture points in mature and immature males and females corroborates the hypothesis of tail breakage as a defense mechanism in this species. All food items found were frogs of the subfamily Leptodactylinae (family Leptodactylidae), most often from the genus Adenomera, followed by Physalaemus, suggesting that D. dendrophis is primarily terrestrial and anurophagous.

Tail autotomy in the common dormouse ( Muscardinus avellanarius): Some ecological aspects

Key words: Muscardinus avellanarius, tail loss, demographic parametersCaudal autotomy – the ability to shed the tail– is a common and well-recognised antipre-dator defence mechanism in reptiles andamphibians. A review of the occurrence ofthis phenomenon in rodents is presented byShargal et al. (1999). These authors state thattail autotomy occurs in at least 35 species andhas evolved separately in eight rodentfamilies, with no clear pattern in systematics,geography, or habitat use. Two major typesof tail loss are recognised in rodents: simul-taneous loss of an entire part of the tail, whenthe tail breaks across vertebrae, and sheddingof a portion of the tail skin alone withsubsequent loss of the denuded part of thetail (Mohr 1941). These two types are calledtrue autotomy and false autotomy, respec-tively (Dubost and Gasc 1987; McKee andAdler 2002).In general, earlier studies of tail loss were notaccompanied by field research, and onlyanatomical/histological aspects of this phe-nomenon were studied (e.g., Go¨gl 1930;Mohr 1941). Several later studies dealt alsowith some ecological aspects of tail loss inrodents: Florida mouse (Peromyscus florida-nus)(Layne 1972), black rat (Rattus rattus)(Michener 1976), common spiny mouse(Acomys cahirinus) and golden spiny mouse(A. russatus)(Shargal et al. 1999) as well asCentral and South American spiny rats(Proechimys)(Dubost and Gasc 1987;McKee and Adler 2002).False tail autotomy in dormice (Gliridae) is awell-known phenomenon, which is men-tioned in some generalised publications onthese rodents (e.g., Vietinghoff-Riesch 1960;Storch 1978; Airapetyants 1983; Morris 1997;Rossolimo et al. 2001). However, onlyanatomical/histological aspects of tail autot-omy have been studied in dormice (Go¨gl1930; Mohr 1941), any ecological aspects ofthis phenomenon were not reflected. The aimof the present study was to analyse thefrequency of occurrence of tail autotomy inseparate demographic groups, annual survi-val rates of tail-less individuals and someother ecological aspects of tail autotomy inthe common dormouse (Muscardinus avella-narius) populations.Studies of two isolated common dormousepopulations were carried out in Lithuania intwo locations: at study site A (south-westernLithuania, Sˇakiai district; 55103

Energetic and locomotor costs of tail loss in the Chinese skink, Eumeces chinensis

Caudal autotomy is a defense mechanism used by numerous lizards to evade predators, but this entails costs. We collected 294 adult Chinese skinks ( Eumeces chinensis) from a population in Lishui (eastern China) to evaluate energetic and locomotor costs of tail loss. Of the 294 skinks, 214 (c. 73%) had previously experienced caudal autotomy. Neither the proportion of individuals with regenerated tails nor the frequency distribution of locations of the tail break differed between sexes. We successively removed four tail segments from each of the 20 experimental skinks (adult males) initially having intact tails. Lipid content in each removed tail segment was measured, and locomotor performance (sprint speed, the maximal length traveled without stopping and the number of stops in the racetrack) was measured for each skink before and after each tail-removing treatment. Another independent sample of 20 adult males with intact tails was measured for locomotor performance to serve as controls for successive measurements taken for the experimental lizards. Caudal lipids were disproportionately stored along the length of the tail, with most lipids being aggregated in its proximal portion. Tail loss significantly affected sprint speed, but not the maximal length of, or the number of stops during the sprint. However, the adverse influence of tail loss on sprint speed was not significant until more than 51% of the tail (in length) was lost. Our data show that partial tail loss due to predatory encounters or other factors may not severely affect energy stores or locomotor performance in E. chinensis. As tail breaks occurred more frequently in the proximal portion of the tail in skinks collected from the field, we conclude that caudal autotomy occurring in nature often incurs substantial energetic and locomotor costs in E. chinensis.