Live Snake Research Articles

Inter-specific variation in anti-predator behavior in sympatric species of kangaroo rat

Kangaroo rats, Dipodomys, occupy desert habitats with little cover and thus are under high predation risk from diverse predators. The behavior used to assess predation risk or to escape capture is unknown. We therefore compared anti-predator behavior of two sympatric species of kangaroo rat of different sizes, D. merriami and D. spectabilis. We first examined whether kangaroo rats use olfaction as a first line of defense against snake predation and tested the rats for their responses to scent extracted from two species of snake that live sympatrically with the kangaroo rats, the Mojave rattlesnake (Crotalus scutulatus) and the gopher snake (Pitophis melanoleucus). We also tested for species differences in anti-predator behavior through 15-min interactions between the kangaroo rats and free-moving gopher snakes. We found that D. spectabilis actively approached the scent of both rattlesnakes and gopher snakes more than controls of vegetable oil and evaporated solvent (Fig. 1). In contrast, D. merriami did not differentiate snake odors from controls in the experimental arena, but they sniffed the sand where a free-moving snake had passed more than D. spectabilis. Both species successfully avoided predation in encounters with live snakes. Although total numbers of approaches and withdrawals were similar (Fig. 2), D. spectabilis spent significantly more time within striking distance of the snake than D. merriami. D. spectabilis approached the head of the snake in 93% of its approaches and often engaged in nose to snout contact with the snake. If the snake struck, D. spectabilis jumped directly backward to avoid a strike and footdrummed at a safe distance. In contrast, D. merriami oriented to the snake more than D. spectabilis, but approached the head in only 41% of the approaches and rarely engaged in nose-to-snout contact. The snakes struck, hissed and decreased predatory approaches with D. spectabilis but not with D. merriami (Fig. 3). These results show that kangaroo rats can behaviorally influence the risk of being preyed on by snakes. The two species differ, however, in how they react to snakes. The larger D. spectabilis confronts snakes while the smaller D. merriami monitors snakes from a safe distance and avoids them.

Population and sex differences in antipredator responses of breeding fathead minnows (Pimephales promelas) to chemical stimuli from garter snakes (Thamnophis radix andT. sirtalis)

We conducted a predator bite survey on a population of fathead minnows (Pimephales promelas) considered to be under substantial predation pressure by western plains garter snakes (Thamnophis radix). Scarring, due to failed predation attempts by garter snakes and crayfish (Orconectes virilis), was observed significantly more often in breeding males than in breeding females and nonbreeding minnows. Likely, territorial nest defense under the edges of rocks along the water's edge, a habitat occupied by crayfish and frequented by snakes, caused the breeding males to be differentially vulnerable to predation. Under controlled laboratory conditions, breeding males from this population exhibited an antipredator response to chemical stimuli from live snakes (T. sirtalis andT. radix) significantly more often than breeding female minnows from the same population and breeding minnows of both sexes from a population that was presumed to be under lower predation pressure from snakes.

Early experience effects on the development of fear in the squirrel monkey

This study was conducted to determine whether juvenile squirrel monkeys exposed to a snake for a 60-min episode during the preweaning period display behavioral and physiological responses to a snake similar to those displayed by feral-born adult monkeys. Juvenile male monkeys born to feral mothers in the lab were either exposed to a live snake during infancy or were snake-naive. Simultaneously tested were adult feral-born and adult lab-born (snake-naive) males. Juveniles exposed as infants to a snake displayed behavioral responses and plasma cortisol elevations following exposure to the snake that were similar to those of feral-born adults. In contrast, the snake-naive monkeys, regardless of age, rarely vocalized at the snake and displayed lower plasma cortisol elevations. These behavioral and physiological responses did not appear to be elicited by a moving animate stimulus per se, insofar as exposure to a moving fish elicited minimal behavioral changes and no cortisol elevations. In contrast to previous findings, these studies indicate that lab-born snake-naive squirrel monkeys are responsive to snakes, but that experience with snakes in infancy produces behavioral and physiological responses more similar to those observed in feral-born monkeys.

Behavioral and physiological responses of mother and infant squirrel monkeys to fearful stimuli.

The behavioral and adrenocortical responses of feral squirrel monkey mothers and their laboratory-born infants were measured following exposure to a live snake and to a flying predator model (hawk). The dyads were either socially or individually housed. The different stimuli were presented above the home cage for 1 hr; behaviors were observed during this period. Blood samples were obtained at the end of the test session and assayed for cortisol. The results indicated that individually housed dyads markedly increased their time spent in contact and their avoidance of the stimuli, and showed increased levels of cortisol when exposed to the snake or hawk model. Socially reared monkeys responded only to the snake. Thus, the presence of social partners ameliorated the response to the hawk model. The marked increase in contact during the presentation of the fear-eliciting stimuli may be partly responsible for the infants' response.

Responses to a live snake by Lemur macaco macaco and Lemur fulvus mayottensis in captivity.

Responses to a live snake by Lemur macaco macaco and Lemur fulvus mayottensis in captivity.

Presleep Suggestion Related to a Phobic Object: Successful Manipulation of Reported Dream Affect

Twenty-four female subjects with a strong dislike of snakes slept for four nonconsecutive nights in the laboratory. They were divided into four groups of six, each group receiving a different presleep suggestion on Nights 3 and 4. On Nights 2, 3, and 4, before sleep, the subjects saw but did not have to touch a live snake and their dreams were collected for each REM period. The results showed that, when compared with the subjects who received the negative affect suggestions, subjects who received positive affect suggestions had significantly higher levels of positive emotions in their dreams, rated their own dreams as more pleasant, and had significantly lower levels of anxiety, sadness, and aggression. These results support the hypothesis that presleep suggestion can be an effective technique in influencing the affective dimension of the dream.

Effects of diazepam on approach, self-reported fear and psychophysiological responses in snake phobics

The effects of diazepam was assessed on a number of measures of phobic anxiety. Snakephobic subjects underwent two sessions on either diazepam or placebo in a crossover design. In addition to a habituation series, a slide with the phobic object was displayed as well as a live snake which subjects were asked to approach. The anxiolytic effect of diazepam was manifest in only one measure of fear, namely self-rated fear at the point of closest approach when it also attained the highest level. The result would indicate that diazepam has an anxiolytic only on high levels of subjective anxiety. The magnitude of the phasic cardiac reaction to the slide was highly and positively correlated with self-rated fear of the slide.

Staging the Obscene Body

Nearly 25 years ago the conceptual and performance artist Carolee Schneemann created a loft art environment, Eye Body, in which she included her own body as one of the materials. Photos of Eye Body showing the naked, beautiful Schneemann, flowers painted on her cheeks, her breasts and body covered with splashes of paint, grease, and chalk, or lying on the floor slithered over by live snakes, speak to the shocking but also the erotic and celebratory nature of her performances. Schneemann has written of the ritual aspect of the process that could put her in a trancelike state, and of her later discovery, through the study of Earth Goddess artifacts, of the sacral implications of the body images explored in that performance (1979:52). In performances created by a number of women in the I98os, Schneemann's sacred body has been replaced by the obscene bodyaggressive, scatalogical, and sometimes pornographic. My purpose here is to gather the scattered evidence of this phenomenon, and to begin to map its location in the fraught contemporary debate over female sexuality, feminism, and pornography. What do these performances say to us about contemporary theatre practice? What does it mean that women are making these performances? And how does one begin to think about these questions: with theories of the avant-garde? Of modernist transgression? Of pornography? With the feminist pornography wars? Though one performance I will write about was unequivocally pornographic (others were borderline, most were only obscene-the boundaries smudge instantly), I started this project by trying to find out what people who have thought about it, think pornography is. At one border of the pornography debate there is a real enjoyment and tolerance of pornography. Its defenders, such as Marxist philosopher Alan Soble, see violent pornography as marginal. Soble makes little distinction

The Treatment of a Snake Phobia by Imaginal Exposure

A severe phobia of snakes was treated by exposure in imagination, no in vivo exposure taking place. Imaginal exposure homework was given with the aid of audio-tapes of the treatment sessions. After treatment, in a behavioural test, the client experienced rapid habituation of anxiety to handling a live snake. The total amount of time taken for the treatment was similar to the time taken in treating other small animal phobics by in vivo exposure alone. It is suggested that for specific phobics the use of imaginal rehearsal prior to in vivo exposure may optimise the conditions under which in vivo exposure takes places and require no more of the therapist's time than the usual in vivo methods.

Live blind snakes (Leptotyphlops dulcis) in eastern screech owl (Otus asio) nests: a novel commensalism.

Eastern screech owls bring live blind snakes to their nestlings, whereas all other prey are delivered dead. Some of the snakes are eaten but most live in nest debris, where they eat soft-bodied insect larvae from the decomposer community in fecal matter, pellets, and uneaten prey. Consumption of larvae may reduce larval parasitism on owl nestlings or larval competition with nestlings for food stored in the nest, because nestlings with live-in blind snakes grow faster and experience lower mortality than same-season broods lacking snakes. We propose a commensalistic association in which the screech owl benefits reproductively and the live-in blind snake is not affected.

Footdrumming and other anti-predator responses in the bannertail kangaroo rat (Dipodomys spectabilis)

Anti-predator behaviors of the bannertail kangaroo rat (Dipodomys spectabilis) toward snake predators were investigated. We induced responses by presenting a live (tethered) snake and an inflatable snake decoy to rats of known ages and sex in their territories. Comparisons of behaviors during spontaneous activity (baseline), naturally occurring snake-rat interactions, and experimental procedures further clarified anti-predator behaviors. The tethered snake immediately induced high rates of footdrumming (the repeated striking of the hind feet on the ground) in all rats (n=24) (Table 2), and individuals of both sexes and all ages footdrummed significantly more at the tethered snake than at the decoy. Other antipredator behaviors included alert postures, jumpback, kicking sand and avoidance. Juvenile rats exhibited more avoidance behavior and alert postures than adults and footdrummed at the decoy only if they experienced the snake first. We conclude that footdrumming functions as an individual alarm signal against predation by snakes in D. spectabilis. The drumming probably informs a snake that it has been detected and may cause it to leave. Because rats did not footdrum in response to aerial predators (owls), we suggest that kangaroo rats use different anti-predator strategies that depend on the kind of threat and the type of predator.

An Analysis of Snake‐Scent Application Behaviour in Siberian Chipmunks (Eutamias sibiricus asiaticus)

AbstractSome rodents assault live snakes by mobbing. Another snake‐directed behaviour is shown by Siberian chipmunks, Eutamias sibiricus asiaticus, when encountering a dead snake. They approach the carcass cautiously, gnaw the snake skin, and chew and apply the gnawed bits to their body fur. We have termed this behaviour “Snake‐Scent Application” (SSA). SSA behaviour is also elicited by snake urine and feces. Chemicals in snake skin and rectal and cloacal sacs release SSA. Snake urine applied to dead mice tends to suppress ingestion by snakes.

Issues in the assessment of fear: Response concordance and prediction of avoidance behavior

A large group of female subjects completed a battery of questionnaires including the Fear Survey Schedule and the Snake Questionnaire. They were later administered a behavioral approach test with a live snake during which self-report, behavioral, and psychophysiological measures were collected. These data were initially used to test Hodgson and Rachman's (Behavior Research and Therapy, 1974,12, 319–326) hypothesis that response concordance varies directly with the strength of emotional arousal. The results indicated that the less fearful subjects produced a greater degree of response concordance—contrary to the hypothesis. Next, previously identified factors extracted from the Snake Questionnaire were examined to determine their ability to predict behavioral avoidance during the test procedure. One factor was suitably predictive of the avoidance criterion. These two sets of results are discussed in terms of a possible explanation for concordance variations and in terms of the potential value of factor scores in subject selection and fear assessment.

How Customs Control the Trade in Wildlife

In June last year a Customs officer at London Airport, suspicious of a cargo of 100 live royal pythons arriving from Ghana, checked the export permit with officials in Accra. They confirmed that the animals had been illegally exported from Ghana. The snakes were seized, and a difficult situation — what to do with 100 illegally imported live snakes? — was resolved by ffPS and the RSPCA jointly agreeing to pay the cost of returning the survivors to Ghana, where, under the guidance of ffPS Consultant, Dr Emmanuel Asibey, head of the Game and Wildlife Department, they were released in a national park. This incident highlights the important part the Customs Service plays in enforcing the Convention on International Trade in Endangered Species, and also some of the problems. Ted Mouat, who is a senior Customs official, describes how they are learning and coping, and how voluntary societies such as ffPS can help.

A Biophysical Analysis of Daily and Seasonal Utilization of Climate Space by a Montane Snake

A model of the energy budget for the wandering garter snake (Thamnophis elegans vagrans) was constructed from equations describing heat flows at the animal's skin surface and body core. A new method was developed for expressing the role of heat transfer from the substrate in influencing body temperature. Convection coefficients were evaluated on live snakes in a wind tunnel and determined to be essentially identical to those for cylinders. Climate space diagrams were generated from energy budget equations for snakes in their natural montane habitats at 2600 m in Larimer County, Colorado. The attainable body temperatures revealed by climate space diagrams show that the physical environments normally encountered by T. elegans are surprisingly harsh. For example, in July the maximum voluntary body temperature (35°C) would be exceeded in open microhabitats (bare ground, rocks, grass) for °5.5—6 h of each clear day. Optimum body temperatures (26—32°C) could be attained for only °1.5—2.5 h each day, and the critical thermal maximum would be exceeded for at least 3 h in bare—ground or rock microhabitats. On cool or cloudy days in May and September, a snake could barely attain the minimum optimum body temperature in any microhabitat.

Behavioral and adrenocorticoid responsiveness of squirrel monkeys to a live snake: Is flight necessarily stressful?

Bolivian and Guyanese squirrel monkeys were assessed for responses to a live boa constrictor snake and to the novelty/disturbance associated with this presentation. Wild-born animals from adult groups which contained males, females, and pregnant females were tested during both individual and group conditions. The latter condition involved placing the empty or snake-occupied wire-mesh stimulus box on top of the group's home cage. In the individual conditions, an animal was removed from the social group cage and placed alone in a vertically oriented test cage with the stimulus box on top. Spatial and behavioral measures were recorded during these 30-min experimental sessions, and blood samples for plasma cortisol analysis were obtained at the end of each weekly session. Blood samples were also taken during undisturbed conditions 1 week before and after the experimental period. All monkeys revealed agitated behavior in the presence of the snake. In contrast, the cortisol levels in response to the snake and empty box were not different for any group of animals. However, the mean of the two individual tests was greater than the mean of the group tests for males, females, or pregnant females. These data support previous studies which indicate that wild-born squirrel monkeys clearly respond with behavioral distress to a live snake. Although cortisol elevations were not specifically produced by exposure to the snake, the responsiveness of the squirrel monkey pituitary—adrenal system to novelty was demonstrated, as all types of monkeys showed significant elevations to the disturbance/novelty of the individual tests.

Reproductive value and appropriateness of response to predators by White-Crowned Sparrows

Twenty-five pair of breeding Whitecrowned Sparrows were presented with a live snake and models of a hawk, jay, and junco. Pairs were tested either when the female was brooding eggs, feeding nestlings, or fledglings. It was found that the snake was responded to the most when the pair had nestlings, very little when the female was brooding eggs, and at a moderate level with fledglings. The hawk and jay models were responded to the least with eggs, more with nestlings, and the most with fledglings. The junco model elicited little response. Both the pattern and level of response is influenced by whether or not the stimulus represents an effective predator at the particular stage of the breeding cycle. They also are influenced by the reproductive value of the progeny. A model is suggested that includes two factors: stimulus value and reproductive value. We propose that this combined model is more suitable than a single factor one.

Responses to snakes by surrogate- and mother-reared squirrel monkeys

Eight behaviors were observed in 1-year-old squirrel monkeys exposed to either a live boa constrictor or one of four inanimate objects with varying similarities to the live snake. The playpen group was exposed to these stimuli both in the presence of their feral mothers and after they had been permanently separated from their mothers. The surrogate group was similarly tested before and after separation from cloth mother surrogates. The principal finding was that the playpen group touched the box containing the stimulus objects for significantly shorter durations than did the surrogate group. The difference occurred both in the presence and in the absence of the mothers or the mother surrogates. This result indicated that the playpen infants had learned to avoid the stimulus box as a consequence of observing their mothers’ marked affective responses to the snake.

An Empirical Test of Three Alternative Explanations for Covert Reinforcement Effects

The empirical validity of the explanations, instrumental-conditioning, counterconditioning, and exposure for covert reinforcement were tested. 45 female students, aged 19 to 35 yr., were subjects. Each was screened for level of fear toward snakes and ability to form clear images. They were randomly assigned to one of five treatment conditions and one of three categories of expectancy. Conditions were covert positive reinforcement, reversed covert positive reinforcement, neutral consequence, reversed covert positive reinforcement to nonsnake stimuli, and nondirective contact. Assessment of expectancy occurred pretreatment and posttreatment, posttreatment only, and no assessment. Results showed that assessment of expectancy did not affect performance on subjective or behavioral measures of fear. All treatment conditions except contact produced significant reductions in fear and increased expectations about ability to approach a live snake. Findings did not support the explanations of instrumental-conditioning, counterconditioning, or exposure. A cognitive-mediational account was offered as an alternative explanation for effects of covert reinforcement.

Marking Live Snakes for Identification of Individuals in Population Studies

(1) A technique of scale clipping live snakes is being used to identify individuals in population studies. (2) To avoid harming the reptile, yet at the same time providing a reliable method of marking, it is necessary only to remove a small part of the ventral acute. The reliability of an alternative method of identifying individuals, that is by photographing certain parts of each animal, is being investigated.