Snake Feeding Research Articles

Coelomic and Muscular Cross-Sectional Areas in Three Families of Snakes

Coelomic and Muscular Cross-Sectional Areas in Three Families of Snakes

Congenital responsiveness of garter snakes to a dangerous prey abolished by learning

In nature, two garter snakes (Thamnophis melanogasterandT.eques) feed on the carrion-eating leechErpobdella punctatabut not on the blood-sucking leechHaementeria officinalis. In the laboratory, although ingestively naive snakes attacked both leeches, onlyE.punctatawas successfully ingested.Haementeria officinalisusually thwarted ingestion or killed the snake. In tests with leech odours, ingestively naiveT.melanogastershowed significant responsiveness only toE.punctata; but in tests with pieces of integument and live leeches, they responded positively to both leeches, responding more strongly toE.punctatthan toH.officinalis. Ingestive and chemosensory responses of litters ofT.melanogasterto the two leeches were correlated, implying possible genetic correlation. In a series of 15 trials with live leeches, snakes presented withH.officinalisprogressively ceased to attack, whereas snakes presented withE.punctatacontinued to attack. Snakes that alternately encounteredH.officinalisandE.punctataceased attackingH.officinalisand continued attackingE.punctata. In a subsequent chemosensory test based on tongue-flicking these snakes showed enhanced discrimination of the two leeches, suggesting that snakes can learn to rejectH.officinalis, a dangerous and probably unprofitable prey, using chemical cues.

Housing and Husbandry of Snakes and Lizards

This is the first of a series of articles by Chris Marshall on the care and treatment of reptiles. It will be followed in subsequent issues by articles on the feeding of snakes, and nutritional bone disease; common veterinary problems of snakes, including respiratory infection and septicaemia; and post hibernation anorexia in tortoises.

Blood pressure during routine activity, stress, and feeding in black racer snakes (Coluber constrictor)

The pressor response to normal daily behaviors and acute stress was studied in black racer snakes (Coluber constrictor) at 30 degrees C. In addition, hematological changes during the stress response were assessed. Mean nighttime systemic arterial blood pressure (SABP) in undisturbed snakes was lower than daytime pressure (26 +/- 3 vs. 32 +/- 9 mmHg, P < 0.001). When snakes were fed mice, SABP increased 3.5- to 4-fold and heart rate increased approximately 3-fold above resting values within approximately 30 s (peak SABP, 99 +/- 18 mmHg; peak heart rate, 99 +/- 12 beats/min). Killing and ingesting the mice required 6-15 min, during which time mean SABP and heart rate were 84 +/- 16 mmHg and 92 +/- 12 beats/min. Pulmonary blood pressure also increased but remained 40-50 mmHg lower than SABP. During stress elicited by tapping the snakes for 5-8 min, heart rate was 94 +/- 6 beats/min but SABP averaged only 44 +/- 11 mmHg. Plasma norepinephrine and epinephrine increased 51- and 26-fold. Plasma glucose increased 58%, hematocrit increased 19%, and plasma volume decreased 19%. It is concluded that blood pressure is markedly affected by behavior and that the sympathetic nervous system appears to play a key role.

Ecology of a Low-Energy Specialist: Food Habits and Reproductive Biology of the Arafura Filesnake (Acrochordidae)

Under the hypothesis that low metabolic rates are adaptations to low rates of energy throughput, taxa with unusually low metabolic rates-such as acrochordid snakes-might be expected to show unusually low rates of feeding, growing, maturing and reproducing. Field studies of Acrochordus arafurae in the Alligator Rivers Region of tropical Australia show that these aquatic snakes feed and reproduce less frequently than do most other snake species studied previously. Published data on other acrochordids suggest similarly low rates. A. arafurae feeds exclusively on fishes, including carrion. Live prey are subdued by constriction. The proportion of freshly-captured snakes containing food (5%) is lower in this species than in most other snakes. Feeding frequency may be very low and digestive efficiency may be unusually high in A. arafurae. Reproduction is seasonal, with an average litter of about 17 young (11-25) depending upon maternal body size. Neonates are large (360 mm, 31 g) and relative clutch mass is high (0.53). However, the proportion of adult-sized females that are reproductive (7%) is lower than in any previously studied snake species, suggesting a low frequency of reproduction in individual females. Population densities and biomass of A. arafurae vary among billabongs, but may reach extraordinarily high levels (100 snakes per hectare, >50 kg per hectare).

Thermal Sensitivity as a Specialization for Prey Capture and Feeding in Snakes

Behavior can be regarded as a result of various processes of decision based on the information provided by the sensory organs. In this review the role of the so-called additional heat sense, next to vision, smell and mechanoreception is discussed with respect to the feeding behavior of snakes. The hierarchy of the sensory information in various phases of the feeding behavior differs between snakes possessing heat receptors (e.g., species of the Crotalinae and Pythoninae) and those without (e.g., species of the Viperinae and Colubrinae). Probably depending on the influence of ecological demands, visual or chemical cues are the main information in the behavioral phases before the strike However, in situations with little visual input, e.g., in darkness, rodents' burrows, etc., hunting behavior is guided in the first place by radiation of warm objects in Crotalus, Python and Trimeresurus flavoviridis, and by substrate vibrations in Vipera aspis, Pituophis melanoleucus and Boa constrictor. I suggest that in the sensory hierarchy, heat information functionally replaces the mechanical information which is utilized by snakes without pit organs. Poststrike behavior on the other hand is mainly guided by chemical cues in all snakes.

Snake Feeding Strategies and Adaptations—Conclusion and Prognosis

Today's symposium has provided elegant demonstrations that being slender may have advantages to snakes; the advantage of slenderness should be easily recognizable to middle-aged members of the audience and to most of us during the post holiday season. In snakes, slenderness allows traverse of crevices off the ground and below the ground; slender snakes can extend their trunk across unstable branches and bridge discontinuous portions of their environment. The adaptations of snakes represent the current state of a process that was already underway in the Cretaceous. Clearly, the process of slenderization did not proceed under constant conditions, for not only did the physical environment shift, but their predators and prey evolved possibly at an accelerated rate due to the success of snake specializations. It is obvious also that the adaptive process affected many aspects of snakes; slenderization involved a profound reorganization. Some aspects may have been abandoned or others appear to have been reformed along the way; it is unlikely that such aspects conferred much advan? tage at the time of loss. The relative advan? tage of some of these aspects may later have increased under different circumstances. Thus, we observe the reversal of trends, for instance the increased stoutness of some Recent species of vipers (Pough and Groves) and the shift from concentration on large prey to feeding on many small items (Greene). Such cases make it likely that the history of snakes includes multiple reversals of trends and development of analogous substitutes. The sequences we dimly dis

Effects of Prey Movement and Prey Odor on Feeding in Garter Snakes

Abstract and SummaryThe role of prey movement in feeding behavior was investigated in 10 garter snakes (Thamnophis sirtalis) repeatedly presented with paired stationary and continuously rotating sections of earthworm (Lumbricus terrestris). Additionally, prey odor intensity and source were varied and the performance of a tongueless snake was compared to normal animals.Experiment 1 showed that garter snakes will selectively attack rotating over nonmoving sections of earthworm across a wide range of speeds (1–2048 rpm) with an optimum between 16 and 256 rpm. However, blocking the odor from the sections and presentation of speeds greater than 500 rpm decreased response to moving sections. Experiment 2 showed that at 22–32 rpm moving sections were selected over stationary sections when odor from both was blocked.Experiment 3 assessed the effects of varying ambient odor conditions upon selection of artificial moving and stationary prey. Ambient earthworm odor resulted in a sustained high rate of tongue‐flicking while, with no odor present, snakes showed a gradually increasing rate of tongue‐flicking that declined within a few minutes.Experiments 4 and 5 studied the effects of tongue removal upon the selection of moving and nonmoving prey. Gross changes in the feeding sequence were noted. A long‐term tongue‐less adult fed by opening her mouth and thrashing about her cage when presented with earthworm odor and only preferred moving prey at 32 rpm; a control showed the normal stalk‐and‐strike sequence. The tongueless snake was less attracted to the moving earthworm at a distance than were normal snakes and the use of vision seemed less integrated rather than compensably improved.The results are discussed in reference to the critical flicker‐fusion frequency, klepto‐parasitism, and escape tactics of prey.

Effects of Chemical and Visual Stimuli upon Chemosensory Searching by Garter Snakes and Rattlesnakes

Many studies indicate that chemical cues activate garter snake feeding behavior whereas visual and/or thermal stimuli do so for rattlesnakes. However, no experiments have factorially combined chemical and visual cues for either of these taxa. The present work explored possible interactive effects of these stimuli on rate of tongue flicking (RTF) in garter snakes (Thamnophis radix haydeni) and rattlesnakes (Crotalus e. enyo, C. v. viridis, and Sistrurus catenatus tergeminus). In Experiments 1 and 2 snakes were exposed to four conditions represent- ing an orthogonal combination of presence vs. absence of visual and chemical stimuli arising from prey. RTF was recorded for 5 min under each condition. Garter snakes exhibited a significant elevation in RTF in the presence of chemical cues whether or not visual cues were present. There was also an effect of visual cues but no interaction between visual and chemical cues. Rattlesnakes did not respond to chemical cues; these snakes showed only an effect of visual cues. In Experiment 3, rattlesnakes were again observed as above, with the exception that test sessions were of 10 min duration. Behavior during the first 5 min was identical to that seen in Experiment 2, but during min 6-10 the snakes responded more in the condition containing visual plus chemical cues than in any other condition. Visual stimuli alerted rattlesnakes to the presence of potential prey and gave rise to elevated RTF which subsequently allowed these predators to utilize chemical cues that happened to be available. Hence, garter snakes and rattlesnakes use both chemical and visual information but differ in the sequence in which these stimuli are used.

Foraging Ecology of the Striped Swamp Snake, Regina alleni, in Southern Florida

The foraging ecology and trophic dynamics of the striped swamp snake, Regina alleni, were studied from 1974—1977 in a south Florida water hyacinth community. The mean standing crop of R. alleni was 30.79 kg (1289 individuals)/ha of water hyacinths. This biomass estimate is greater than that known for any snake species and is related to (1) the high primary productivity of water hyacinths; (2) the trophic positions, diets, and concomitant abundances of the snake's prey; (3) the availability of alternate habitats for exploitation; and (4) release from certain competitive and predatory pressures. Snake density was lowest in summer, increased in fall and winter, then decreased in spring. Changes in density apparently represent seasonal movements of snakes between the hyacinth habitat and the surrounding marshes, in response to fluctuations in water level, prey availability, and predator pressure. R. alleni showed dramatic seasonal and ontogenetic shifts in food habits. Young R. alleni (120—200 mm snout—vent length [SVL]) fed primarily on libellulid odonate naiads but switched to seasonally abundant palaemonid shrimp and astacid crayfish. Between 200 and 300 mm SVL a major dietary shift occurred and crayfish gradually replaced odonates and shrimp. This change occurs throughout the range of the species and also involves a reorganization of snake feeding behavior to accommodate prey of different shapes. The ecological and energetic consequences of this dietary shift are interpreted in terms of the divergent life histories and growth patterns of the predator and its prey. Within the specialized trophic niche of R. alleni, food availability and predator size largely determined the types and sizes of prey consumed, but interacted with the thermal regime, energetic requirements, and foraging efficiencies of individual snakes to determine the rate of food intake. In most seasons juvenile R. alleni consumed more but smaller prey than adults, and the mean percent of snake body mass eaten per day was higher for adults. However, because juveniles fed on odanate naiads that were higher in protein but lower in ash content than the decapods taken by adults, the energetic intake per gram snake body mass was generally higher in juveniles. The predatory impact of R. alleni may be a significant factor limiting the growth of both the snake and its prey populations. During fall, when measured rates of food intake were highest, adult R. alleni consumed °9.6% of the adult crayfish population. In contrast, juveniles accounted for removal of °90.7% of the odonate population in the same time period. When given an unlimited food supply in the laboratory, the daily energetic intake of juveniles was more than two times that of maximum field estimates.

Feeding in water snakes: An electromyographic study

AbstractSynchronized cinematography and electromyography were used to study feeding behavior in water snakes, Nerodia rhombifera and Nerodia fasciata. While these species swallow their prey by alternate movements of the right and left toothed bones of the skull, the muscles show bilateral asymmetric activity during each movement.Opening of one side of the mouth is initiated by protraction of the palatomaxillary arch and slight depression of the mandible. These movements serve to disengage the teeth from the surface of the prey and correlate with activity of the protractors of the palatomaxillary arch and quadrate. Continued opening results primarily from rotation of the braincase around its longitudinal axis. During the latter half of the opening phase, the rates of protraction of both palatomaxillary arch and mandible increase; this correlates with increased activity of the depressor mandibulae, several of the mandibular adductors and three of the four cervical muscles analyzed. The cervical muscles appear to restrain the prey during the fast segment of mouth opening when the toothed bones reach their maximum displacements from the surface of the prey.Closing of the mouth is initiated by rapid depression of the palatopterygoid joint which correlates with a cessation of activity of the levator pterygoidei. Immediately thereafter, the posterior end of the maxilla is depressed and slightly retracted and the mandible tends to be protracted and slightly adducted. These movements correlate with synchronized activity of the palato‐maxillary protractors, the pterygoideus and the depressor mandibulae. The rest of the closing phase consists primarily of adduction and retraction of the palatomaxillary and mandibular elements relative to the braincase; the toothed bones remain fixed to the surface of the prey while the braincase is moved forward. EMGs indicate that the complex bone movements of the latter stage of mouth opening and the initial stage of mouth closing are dependent upon the simultaneous firing of a number of morphologically antagonistic muscles.

Roles of the vomeronasal and olfactory systems in prey attack and feeding in adult garter snakes

Adult garter snakes preoperatively responded with more attacks and higher tongue-flick rates to earthworm extract soaked cotton swabs than to distilled water soaked swabs. Snakes with vomeronasal nerve lesions (N=6) failed to differentially respond to earthworm extract or to eat earthworm bits following surgery. Olfactory (N=6) and sham (N=6) nerve surgeries did not disrupt responding to swabs or earthworms.

Prey Capture in the Cottonmouth Snake (Agkistrodon piscivorus)

Using direct observation and frame-by-frame analysis of high speed motion pictures taken of snake feeding activity, 6 continuous phases are identified and a seventh (search) postulated that collectively represent the activity of prey capture by the cottonmouth snake. The first phase of prey capture is the search wherein the snake moves through its habitat in such a fashion as to increase the likelihood of locating prey. Approach phase follows during which the snake closes on the located prey. After drawing its body into s-shaped curves or coils, the neck and trunk curves gradually open to slowly move the head a short distance toward the prey; this is the glide phase. The rapid strike phase ensues followed by the bite, release, and post-release phases during which respectively, the jaws close on the prey and venom is injected, prey is released, and finally the envenomated prey is relocated and

Role of the tongue and senses in feeding of naive and experienced garter snakes

Prey attack behavior was studied in two species of garter snakes ( Thamnophis sirtalis and T. radix). Newborn, ingestively naive, and experienced snakes had their tongues severed surgically, while control groups retained their tongues. Attack latency, tongue flick frequency and an orientation-interest measure were recorded for each subject on responses to extracts prepared from species-characteristic prey. Feeding, as well as responses to prey extracts, were found to be suppressed almost totally in the tongueless naive snakes. A detongued adult, however, readily ate although its behavior was abnormal. Temporary blind and anosmic conditions did not have a significant effect on response rates of the tongueless or control groups. While importance of the tongue-Jacobson's organ system is demonstrated, the length of tongue removed and presurgery experience are important factors.

The Use of Powdered Earthworm in the Feeding of Snakes

The Use of Powdered Earthworm in the Feeding of Snakes

Observations on the feeding, shedding and growth rates of captive snakes (Boidae)

Observations on the feeding, shedding and growth rates of captive snakes (Boidae)

THE FEEDING MECHANISM OF SNAKES AND ITS POSSIBLE EVOLUTION

ful?of living reptiles. More than 3000 forms of snakes have become specialized for marine, freshwater aquatic, terrestrial, arboreal, and fossorial modes of life, enabling them to invade all continents (but Antarctica) and many oceans. Most popular atten? tion has traditionally been directed to as? pects of the ophidian feeding mechanism, particularly to the use of venom and to the ability to ingest spectacularly large prey. Recently there has been a revival of in? terest in snake feeding, as indicated by a series of studies attempting to correlate morphological and behavioral observations (cf. Gans, 1952; Dullemeijer, 1956, 1959; Kochva, 1958; Frazzetta, 1959; Albright and Nelson, 1959, 1959a). These studies were based to a considerable extent upon the pioneer analyses of snake head muscles car? ried out by Haas (1929, 1930, 1930a, 1930b, 1931, 1931a, 1932, 1934, 1952, and 1955) and also by Anthony and Serra (1950, 1951) us? ing a modification of the nomenclature established by Lakjer (1926). Although these authors proceeded from different viewpoints and used divers nomenclatures for morphological and func-

California Lyre Snake Feeding on the Pocketed Bat

Journal Article California Lyre Snake Feeding on the Pocketed Bat Get access Philip H. Krutzsch Philip H. Krutzsch 1536 31st Street, San Diego, California Search for other works by this author on: Oxford Academic Google Scholar Journal of Mammalogy, Volume 25, Issue 4, 12 December 1944, Pages 410–411, https://doi.org/10.1093/jmammal/25.4.410-b Published: 12 December 1944

An Improved Method of Snake Feeding

An Improved Method of Snake Feeding

42. Notes on the Feeding of Snakes in Captivity.

Some years ago, in a paper contributed to the ‘Proceedings' of the Society by Dr. Chalmers Mitchell and Mr. R. I. Pocock, entitled “The Feeding of Reptiles in Captivity” (P.Z.S. 1907, p. 785), a general account was given of the feeding habits of the Snakes then living in the Gardens, together with records of a large number of individual specimens, showing the amount consumed between the months of May and October. My own general observations tally with those of Dr. Mitchell and Mr. Pocock, and my object in presenting this paper is to lay before the Society some additional facts, to show how unnecessary it is to feed the snakes on live creatures, and to give a detailed record of the amount taken and of the regularity of the meals in a number of specimens over a period of a year.