Comment — Missed opportunities in the study of activity and body temperature of beaver (Castor canadensis)

1994 ◽  
Vol 72 (3) ◽  
pp. 567-569 ◽  
Author(s):  
Jacques Bovet

Two papers published recently in this journal have examined the relationship between patterns of activity and patterns of body temperature in free-ranging beavers in winter (D.W. Smith, R.O. Peterson, T.D. Drummer, and D.S. Sheputis, 1991. Can. J. Zool. 69: 2178–2182; and A. P. Dyck and R.A. MacArthur, 1992. Can. J. Zool. 70: 1668–1672). I argue that both papers missed their objective, owing to the use of procedures that were inadequate to detect and (or) characterize behavioral or physiological rhythms that were free-running with periods ≠ 24 h.

1979 ◽  
Vol 57 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Robert A. MacArthur

Radiotelemetry techniques were employed to study the relationship between activity and abdominal temperature (Tb) changes in free-ranging muskrats (Ondatra zibethicus). Body cooling accompanied foraging activity by adults in winter and juveniles in summer and was retarded by periodic withdrawal from water. Net Tb decline during winter foraging rarely exceeded 2 °C and was relatively independent of foraging time for excursions exceeding 40 min duration. In addition to periodic rewarming within feeding shelters, muskrats appeared to avoid hypothermia during under-ice excursions by elevating Tb prior to entering water. This elevation was maximal (mean increase = 1.2 °C) for excursions exceeding 40 min duration. Comparable increases were not observed in summer.


1992 ◽  
Vol 70 (9) ◽  
pp. 1668-1672 ◽  
Author(s):  
Alvin P. Dyck ◽  
Robert A. MacArthur

Daily activity and body temperature patterns of beavers (Castor canadensis) were monitored in the field with an automated radiotelemetry system from June 1988 through March 1989. Body temperatures of kits and adults averaged close to 37 °C throughout the year, with no evidence of seasonal hypothermia. The greatest temperature changes accompanied episodes of aquatic activity. Body temperature typically dropped 1.0–1.5 °C during periods when beavers were absent from the lodge, then recovered when animals returned to the house. Throughout the open-water season (20 June – 1 November), both age groups demonstrated a daily rhythm in body temperature characterized by a gradual rise between 06:00 and 18:00 followed by a general decline during the nocturnal active period. During the ice-bound season (2 November – 15 March), there was little evidence of a distinct daily rhythm in activity or body temperature, especially in adults. Both age groups exhibited a 0.22–0.64 °C increase in mean body temperature during the 3-h period preceding the first trip in each sequence of excursions away from the lodge. We propose that this predeparture rise in temperature may contribute to the avoidance of immersion hypothermia in foraging beavers.


SLEEP ◽  
2021 ◽  
Author(s):  
Yi-Ge Huang ◽  
Sarah J Flaherty ◽  
Carina A Pothecary ◽  
Russell G Foster ◽  
Stuart N Peirson ◽  
...  

Abstract Study objectives Torpor is a regulated and reversible state of metabolic suppression used by many mammalian species to conserve energy. Whereas the relationship between torpor and sleep has been well-studied in seasonal hibernators, less is known about the effects of fasting-induced torpor on states of vigilance and brain activity in laboratory mice. Methods Continuous monitoring of electroencephalogram (EEG), electromyogram (EMG) and surface body temperature was undertaken in adult, male C57BL/6 mice over consecutive days of scheduled restricted feeding. Results All animals showed bouts of hypothermia that became progressively deeper and longer as fasting progressed. EEG and EMG were markedly affected by hypothermia, although the typical electrophysiological signatures of NREM sleep, REM sleep and wakefulness enabled us to perform vigilance-state classification in all cases. Consistent with previous studies, hypothermic bouts were initiated from a state indistinguishable from NREM sleep, with EEG power decreasing gradually in parallel with decreasing surface body temperature. During deep hypothermia, REM sleep was largely abolished, and we observed shivering-associated intense bursts of muscle activity. Conclusions Our study highlights important similarities between EEG signatures of fasting-induced torpor in mice, daily torpor in Djungarian hamsters and hibernation in seasonally-hibernating species. Future studies are necessary to clarify the effects on fasting-induced torpor on subsequent sleep.


2021 ◽  
Vol 7 (1) ◽  
pp. 1930932
Author(s):  
Matiwos Habte ◽  
Mitiku Eshetu ◽  
Melesse Maryo ◽  
Dereje Andualem ◽  
Abiyot Legesse ◽  
...  

Author(s):  
Simone Anzá ◽  
Bonaventura Majolo ◽  
Federica Amici

AbstractGenerally, nonreproductive sex is thought to act as “social grease,” facilitating peaceful coexistence between subjects that lack close genetic ties. However, specifc nonreproductive sexual behaviors may fulfill different functions. With this study, we aimed to test whether nonreproductive mounts in Barbary macaques are used to 1) assert dominance, 2) reinforce social relationships, and/or 3) solve conflicts. We analyzed nonreproductive mounts (N = 236) and postmount behavior in both aggressive and nonaggressive contexts, in 118 individuals belonging to two semi-free-ranging groups at La Montagne des Singes (France). As predicted by the dominance assertion hypothesis, the probability to be the mounter increased with rank difference, especially in aggressive contexts (increasing from 0.066 to 0.797 in nonaggressive contexts, and from 0.011 to 0.969 in aggressive contexts, when the rank difference was minimal vs. maximal). The strength of the social bond did not significantly predict the proportion of mounts across dyads in nonaggressive contexts, providing no support for the relationship reinforcement hypothesis. Finally, in support of the conflict resolution hypothesis, when individuals engaged in postconflict mounts, 1) the probability of being involved in further aggression decreased from 0.825 to 0.517, while 2) the probability of being involved in grooming interactions with each other increased from 0.119 to 0.606. The strength of the social bond between former opponents had no significant effect on grooming occurrence and agonistic behavior after postconflict mounts. Overall, our findings suggest that nonreproductive mounts in Barbary macaques have different functions that are not affected by the strength of the social bond.


Behaviour ◽  
2017 ◽  
Vol 154 (7-8) ◽  
pp. 875-907 ◽  
Author(s):  
Erica S. Dunayer ◽  
Carol M. Berman

Throughout the primate order, individuals are highly motivated to handle infants that are not their own. Given the differing and often conflicting interests of the various participants in handling interactions (handler, infant, and mother), most functional hypotheses are specific to particular handling roles. Here we explore one hypothesis that may apply to all participants, but that has received relatively little attention: that handling may facilitate the formation and maintenance of social bonds. Using free-ranging rhesus macaques (Macaca mulatta) on Cayo Santiago, we examine the relationship between infant handling in the early weeks and the strength and diversity of infant social bonds months later, when infant relationships were more independent from those of their mothers. Our results largely confirm the influence of several social characteristics (kinship, rank, sex, and age) in governing handling interactions. They also provide the first evidence that early handling is associated with later social bonds that are stronger than expected based on these social characteristics. However, the enhancement of bonds is largely confined to related handlers; frequent unrelated handlers did not generally go on to form strong bonds with infants. This suggests that kinship may be a sort of prerequisite to the enhancement of social bonds via handling. Given the adaptive benefits of strong social bonds among adult primates, future research should investigate whether early infant handling may have longer term fitness effects.


2001 ◽  
Vol 79 (10) ◽  
pp. 1885-1890 ◽  
Author(s):  
Robert MR Barclay ◽  
Cori L Lausen ◽  
Lydia Hollis

With the development of small implantable data loggers and externally attached temperature-sensitive radio transmitters, increasing attention is being paid to determining the thermoregulatory strategies of free-ranging birds and mammals. One of the constraints of such studies is that without a direct measure of metabolic rate, it is difficult to determine the significance of lowered body temperatures. We surveyed the literature and found that many different definitions have been used to discriminate torpor from normothermy. Many studies use arbitrary temperature thresholds without regard for the normothermic body temperature of the individuals or species involved. This variation makes comparison among studies difficult and means that ecologically and energetically significant small reductions in body temperature may be overlooked. We suggest that normothermic body temperature for each individual animal should be determined and that torpor be defined as occurring when the body temperature drops below that level. When individuals' active temperatures are not available, a species-specific value should be used. Of greater value, however, are the depth and duration of torpor bouts. We suggest several advantages of this definition over those used in the past.


1999 ◽  
Vol 277 (3) ◽  
pp. R812-R828 ◽  
Author(s):  
B. Pitrosky ◽  
R. Kirsch ◽  
A. Malan ◽  
E. Mocaer ◽  
P. Pevet

Daily administration of melatonin or S20098, a melatonin agonist, is known to entrain the free-running circadian rhythms of rats. The effects of the duration of administration on entrainment were studied. The animals demonstrated free-running circadian rhythms (running-wheel activity, body temperature, general activity) in constant darkness. Daily infusions of melatonin or S20098 for 1, 8, or 16 h entrained the circadian rhythms to 24 h. Two daily infusions of 1 h (separated by 8 h) entrained the activity peak within the shorter time interval. The entraining properties of melatonin and S20098 were similar and were affected neither by pinealectomy nor by infusion of 1- or 8-h duration. However, with 16-h infusion, less than half of the animals became entrained. Once entrained, the phase angle between the onset of infusion and the rhythms (onset of activity or acrophase of body temperature) increased with the duration of infusion. Before entrainment, the free-running period increased with the duration of infusion, an effect that was not predictable from the phase response curve.


Author(s):  
W.B.P.N. Herath ◽  
R.A.K.I. Ranasinghe ◽  
M.P.C. Sandaru ◽  
I.A.S. Lakmali ◽  
A.G.N.K. Aluthgama ◽  
...  

Addressing the emotional and mental health of the bedridden elderly is necessary as they are more likely to be depressed being isolated and dependent on a caregiver for a prolonged time. Several studies have been carried out to identify the mental stress of patients through their skin conductivity. The variations in the sympathetic nervous system reflect the emotional state of a person. This is demonstrated by the Galvanic Skin Response and thus can be used as a denotation of psychological or physiological arousal. Such arousal causes the blood capillary dilation, increment of sweat gland activities making the skin further conductive to electricity. In this study we develop a sensor module composed of a Galvanic Skin Response sensor for the bed ridden elderly and identify the relationship between body temperature, heart rate and GSR of them. The experiment is conducted upon 10 bed ridden elderly aged from 60 – 80 years of the Mihinthale region. The observations demonstrate a correlation between the heart rate, body temperature, skin conductivity and the human physiological states.


Sign in / Sign up

Export Citation Format

Share Document