scholarly journals The Effects of Temperature on the Kinematics of Rattlesnake Predatory Strikes in Both Captive and Field Environments

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
M D Whitford ◽  
G A Freymiller ◽  
T E Higham ◽  
R W Clark

Abstract The outcomes of predator–prey interactions between endotherms and ectotherms can be heavily influenced by environmental temperature, owing to the difference in how body temperature affects locomotor performance. However, as elastic energy storage mechanisms can allow ectotherms to maintain high levels of performance at cooler body temperatures, detailed analyses of kinematics are necessary to fully understand how changes in temperature might alter endotherm–ectotherm predator–prey interactions. Viperid snakes are widely distributed ectothermic mesopredators that interact with endotherms both as predator and prey. Although there are numerous studies on the kinematics of viper strikes, surprisingly few have analyzed how this rapid movement is affected by temperature. Here we studied the effects of temperature on the predatory strike performance of rattlesnakes (Crotalus spp.), abundant new world vipers, using both field and captive experimental contexts. We found that the effects of temperature on predatory strike performance are limited, with warmer snakes achieving slightly higher maximum strike acceleration, but similar maximum velocity. Our results suggest that, unlike defensive strikes to predators, rattlesnakes may not attempt to maximize strike speed when attacking prey, and thus the outcomes of predatory strikes may not be heavily influenced by changes in temperature.

2020 ◽  
Vol 223 (14) ◽  
pp. jeb223859 ◽  
Author(s):  
Malachi D. Whitford ◽  
Grace A. Freymiller ◽  
Timothy E. Higham ◽  
Rulon W. Clark

ABSTRACTMovements of ectotherms are constrained by their body temperature owing to the effects of temperature on muscle physiology. As physical performance often affects the outcome of predator–prey interactions, environmental temperature can influence the ability of ectotherms to capture prey and/or defend themselves against predators. However, previous research on the kinematics of ectotherms suggests that some species may use elastic storage mechanisms when attacking or defending, thereby mitigating the effects of sub-optimal temperature. Rattlesnakes (Crotalus spp.) are a speciose group of ectothermic viperid snakes that rely on crypsis, rattling and striking to deter predators. We examined the influence of body temperature on the behavior and kinematics of two rattlesnake species (Crotalus oreganus helleri and Crotalus scutulatus) when defensively striking towards a threatening stimulus. We recorded defensive strikes at body temperatures ranging from 15–35°C. We found that strike speed and speed of mouth gaping during the strike were positively correlated with temperature. We also found a marginal effect of temperature on the probability of striking, latency to strike and strike outcome. Overall, warmer snakes are more likely to strike, strike faster, open their mouth faster and reach maximum gape earlier than colder snakes. However, the effects of temperature were less than would be expected for purely muscle-driven movements. Our results suggest that, although rattlesnakes are at a greater risk of predation at colder body temperatures, their decrease in strike performance may be mitigated to some extent by employing mechanisms in addition to skeletal muscle contraction (e.g. elastic energy storage) to power strikes.


2013 ◽  
Vol 59 (6) ◽  
pp. 718-724 ◽  
Author(s):  
Mei-Xian Wu ◽  
Ling-Jun Hu ◽  
Wei Dang ◽  
Hong-Liang Lu ◽  
Wei-Guo Du

Abstract The significant influence of thermal acclimation on physiological and behavioral performance has been documented in many ectothermic animals, but such studies are still limited in turtle species. We acclimated hatchling soft-shelled turtles Pelodiscus sinensis under three thermal conditions (10, 20 and 30°C) for 4 weeks, and then measured selected body temperature (Tsel), critical thermal minimum (CTMin) and maximum (CTMax), and locomotor performance at different body temperatures. Thermal acclimation significantly affected thermal preference and resistance of P. sinensis hatchlings. Hatchling turtles acclimated to 10°C selected relatively lower body temperatures and were less resistant to high temperatures than those acclimated to 20°C and 30°C. The turtles’ resistance to low temperatures increased with a decreasing acclimation temperature. The thermal resistance range (i.e. the difference between CTMax and CTMin, TRR) was widest in turtles acclimated to 20°C, and narrowest in those acclimated to 10°C. The locomotor performance of turtles was affected by both body temperature and acclimation temperature. Hatchling turtles acclimated to relatively higher temperatures swam faster than did those acclimated to lower temperatures. Accordingly, hatchling turtles acclimated to a particular temperature may not enhance the performance at that temperature. Instead, hatchlings acclimated to relatively warm temperatures have a better performance, supporting the “hotter is better” hypothesis.


1963 ◽  
Vol 18 (5) ◽  
pp. 1016-1018 ◽  
Author(s):  
J. A. Panuska ◽  
Vojin Popovic

Inexperienced shaved adult white rats cooled to a colonic temperature of 18.5 C and then rewarmed to 26.0 C, were placed at an ambient temperature of 2.0 C with the possibility of using a lever-activated heat reinforcement apparatus. Their body temperatures leveled at 29 C; and during the next 40–80 min the rats either learned to press the lever systematically for external heat and thereby rewarmed themselves to euthermia, or they drifted into deeper hypothermia leading to death. Activity records and visual observations indicate that after an average of 48 min and at a body temperature of 29.6 C (28.5–30.2 C), out of a group of 14 rats 12 learned this technique necessary for their survival. All 12 rats reached euthermia and continued to use the lever as long as they remained in the experimental situation. It is concluded that learning is possible even at a low body temperature of 29.6 C. performance; heat reinforcement; temperature regulation; body temperature; environmental temperature; operant behavior; survival studies; motivation; physiology of learning; cold physiology Submitted on March 7, 1963


1979 ◽  
Vol 237 (5) ◽  
pp. R297-R300 ◽  
Author(s):  
E. Dillmann ◽  
D. G. Johnson ◽  
J. Martin ◽  
B. Mackler ◽  
C. Finch

Iron-deficient rats have increased blood and urinary catecholamines regardless of whether anemia is or is not present. The catecholamine response in both iron-deficient and control animals is largely temperature dependent, showing little difference at the isothermic temperature of 30 degrees C but a two- to threefold increase in iron-deficient animals over controls at lower temperatures. The iron-deficient rat is unable to maintain body temperature at 4 degrees C and this is independent of anemia or of food intake. When animals are run on the treadmill for 4 h, body temperatures increase but the difference observed at 4 degrees C between iron-deficient and control animals persists. The underlying abnormality in temperature regulation and in catecholamine response disappeared after 6 days of iron therapy.


1990 ◽  
Vol 259 (2) ◽  
pp. R253-R258 ◽  
Author(s):  
A. F. Bennett

The thermal dependence of locomotor performance capacity, particularly speed and endurance, in vertebrate ectotherms is examined. Most studies have found an optimal speed for performance at relatively high body temperatures, close to upper lethal limits. These performance capacities decrease markedly at low body temperatures and may be compensated by increments in aggressive or evasive behaviors. Relative ranking of performance is maintained among individuals across body temperatures. Acclimation of performance capacities is generally incomplete or entirely absent: most animals compensate locomotor performance rather poorly to cold exposure. Locomotor performance in different groups has been shown to possess the attributes (e.g., variability, repeatability, heritability, and differential survivorship) necessary for evolutionary adaptation, but interpretation of comparative data is complicated by phylogenetic differences among species studied. Controlled studies show partial but incomplete adaptation to environmental temperature.


1960 ◽  
Vol 11 (5) ◽  
pp. 871 ◽  
Author(s):  
DF Dowling

An experiment was performed to test the effect of solar radiation on the body temperatures of cattle, both clipped and with hair coat, in a clear transparent plastic covering as compared with cattle in a white reflective plastic covering. The mean body temperature of the animals in white plastic coats was 0.15°F lower than that of animals in clear plastic coats. This difference was highly significant statistically (P< 0.001). Animals in both clear and white coats had higher body temperatures than controls without plastic coats. The difference was highly significant, and was about 1.5°F in the clipped animals.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244458
Author(s):  
Sarah Hews ◽  
Zahkeyah Allen ◽  
Adrienne Baxter ◽  
Jacquline Rich ◽  
Zahida Sheikh ◽  
...  

Behavioral thermoregulation is an important defense against the negative impacts of climate change for ectotherms. In this study we examined the use of burrows by a common intertidal crab, Minuca pugnax, to control body temperature. To understand how body temperatures respond to changes in the surface temperature and explore how efficiently crabs exploit the cooling potential of burrows to thermoregulate, we measured body, surface, and burrow temperatures during low tide on Sapelo Island, GA in March, May, August, and September of 2019. We found that an increase in 1°C in the surface temperature led to a 0.70-0.71°C increase in body temperature for females and an increase in 0.75-0.77°C in body temperature for males. Body temperatures of small females were 0.3°C warmer than large females for the same surface temperature. Female crabs used burrows more efficiently for thermoregulation compared to the males. Specifically, an increase of 1°C in the cooling capacity (the difference between the burrow temperature and the surface temperature) led to an increase of 0.42-0.50°C for females and 0.34-0.35°C for males in the thermoregulation capacity (the difference between body temperature and surface temperature). The body temperature that crabs began to use burrows to thermoregulate was estimated to be around 24°C, which is far below the critical body temperatures that could lead to death. Many crabs experience body temperatures of 24°C early in the reproductive season, several months before the hottest days of the year. Because the use of burrows involves fitness trade-offs, these results suggest that warming temperatures could begin to impact crabs far earlier in the year than expected.


2012 ◽  
Vol 8 (5) ◽  
pp. 868-870 ◽  
Author(s):  
A. Daniella Rojas ◽  
Gerhard Körtner ◽  
Fritz Geiser

Mammalian torpor saves enormous amounts of energy, but a widely assumed cost of torpor is immobility and therefore vulnerability to predators. Contrary to this assumption, some small marsupial mammals in the wild move while torpid at low body temperatures to basking sites, thereby minimizing energy expenditure during arousal. Hence, we quantified how mammalian locomotor performance is affected by body temperature. The three small marsupial species tested, known to use torpor and basking in the wild, could move while torpid at body temperatures as low as 14.8–17.9°C. Speed was a sigmoid function of body temperature, but body temperature effects on running speed were greater than those in an ectothermic lizard used for comparison. We provide the first quantitative data of movement at low body temperature in mammals, which have survival implications for wild heterothermic mammals, as directional movement at low body temperature permits both basking and predator avoidance.


2002 ◽  
Vol 205 (14) ◽  
pp. 2099-2105 ◽  
Author(s):  
K. Mark Wooden ◽  
Glenn E. Walsberg

SUMMARYThis study quantifies the thermoregulatory ability and energetics of a mammal, the round-tailed ground squirrel Spermophilus tereticaudus,that can relax thermoregulatory limits without becoming inactive. We measured body temperature and metabolic rate in animals exposed for short periods (1 h)to air temperatures ranging from 10 to 45 °C and for long periods (8 h) to air temperatures ranging from 10 to 30 °C. Within 45 min of exposure to air temperatures ranging from 10 to 45 °C, the mean body temperatures of alert and responsive animals ranged from 32.1 °C(Tair=10 °C) to 40.4 °C(Tair=45 °C). This thermolability provided significant energetic savings below the thermoneutral zone, ranging from 0.63 W (18 %) at 10 °C to 0.43 W (43 %) at 30 °C. When exposed for 8 h to air temperatures between 10 and 30 °C, animals varied their body temperature significantly over time. At all air temperatures, the lowest body temperature(maintained for at least 1 h) was 31.2 °C. The highest body temperatures(maintained for at least 1 h) were 33.6 °C at 10 °C, 35.3 °C at 20°C and 36.3 °C at 30 °C. The energetic savings realized by maintaining the minimum rather than the maximum body temperature was 0.80 W(25 %) at 10 °C, 0.71 W (33 %) at 20 °C and 0.40 W (47 %) at 30°C. This study demonstrates in several ways the ability of this species to adjust energy expenditure through heterothermy.


1961 ◽  
Vol 12 (6) ◽  
pp. 1152 ◽  
Author(s):  
G Alexander

Studies were made on temperature regulation of lambs in a closed circuit indirect calorimeter. Dry new-born lambs were able to maintain normal body temperature in ambient temperatures as low as -5°C. This was accomplished by increasing heat production to 2–3 times "basal" levels, apparently by increased oxidation of fats, and by reducing heat loss through the extremities by vasoconstriction. The lower limit of the zone of thermal neutrality was about 29°C. In unsuckled lambs within 24 hr of birth, the heat produced in response to cold appeared to be independent of pre-natal nutrition and age. It was considerably lower in lambs with hairy coats than in lambs with fine coats. Milk intake increased heat production, and this increase was abolished after 12 hr of fasting in lambs up to 3 days old, but the increase persisted in older lambs. The increase was accompanied by, and was apparently due to, elevated heat loss from the extremities, which persisted even at low temperatures. The maximal thermal insulation of the tissues, calculated from these results, was about 1 Clo; that of the fleece plus air was only 1 to 2 Clo.


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