Seasonal variations of thyroid activity in the adult male badger, (Meles meles L.)

Maurel, Daniel; Boissin, J.

doi:10.1016/0016-6480(79)90208-9

Cited by 22 publications

(6 citation statements)

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“…The seasonal variations of thyroid activity are comparable to those already observed in the same species (Maurel and Boissin, 1979). A study conducted from 1975 to 1980 showed that the seasonal variations of the plasma thyroxine level are always characterized by a minimum located at the end of autumn and during winter and by higher values in spring and at the end of summer or early autumn; the plasma thyroxine levels measured during summer are always considerable, but the mean level may vary from year to year (Maurel, 1981).…”

Section: Discussionsupporting

confidence: 83%

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Seasonal rhythms of locomotor activity and thyroid function in male badgers(Meles melesL.)

Maurel

Boissin

1983

Journal of Interdisciplinary Cycle Research

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Adult male badgers were housed in outdoor pens equipped with an infra-red actographic system, in the Chizé forest (Western France: 46°19'N; 00°24'W). Various parameters characterizing the diurnal general locomotor activity rhythm were measured: duration of the total activity phase and the actual activity outside the burrow in relation to sunset, sunrise or night duration, activity of passage and profile of seasonal variations. Simultaneously the thyroid activity was controlled by bi-monthly or monthly measurements of plasma thyroxine concentration.1. In the nycthemeral rhythm of general locomotor activity, there is a close synchronization between the beginning of the activity phase and sunset; nevertheless, from November to March, the beginning of activity occurs 2 h or more after sunset. The end of activity always takes place before the sunrise ("anticipation mechanism") and the delay exhibits a seasonal variation (minimum in summer, maximum in late autumn-early winter).2. General locomotor activity is minimal in January; the phase duration is maximal in summer, then decreases at the end of the season reaching a reduced level from November onwards. During spring and early autumn, we measured an intense passage activity. This was considerably reduced in early winter.These seasonal variations of the nycthemeral rhythm of the general locomotor activity were considered in relation to the annual cycle of the plasma thyroxine concentration. Two periods of high hormonal level were observed: in spring and late summer-early autumn. The lowest thyroxine concentrations were measured at the end of autumn and winter. Hence, late autumn-early winter is a period during which in the badger, both thyroid activity and general activity are considerably reduced. This state may be called "wintering"; during "wintering", badgers may stay many days in the nest, without food.

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Section: Discussionsupporting

confidence: 83%

“…After centrifugation the plasma was stored at -25°C until assayed. Following validation tests total plasma thyroxine was measured using the isotopic competition technique described by Vigouroux (1972) and previously used in the badger (Maurel and Boissin, 1979).…”

Section: // Determination Of Plasma Thyroxine Concentrationsmentioning

confidence: 99%

Seasonal rhythms of locomotor activity and thyroid function in male badgers(Meles melesL.)

Maurel

Boissin

1983

Journal of Interdisciplinary Cycle Research

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“…Despite some conspicuous physiological differences from deep hibernators, Slonin (1952) and Johannson (1957) found that the European badger does exhibit some characteristics common to species which undergo torpor. Physiological changes, such as depressed plasma thyroxin titres, associated with inanition and inactivity (Ringberg & 0en, 1978, Maurel & Boissin, 1979and Maurel, 1981 in overwintering badgers were similar to those described in deep hibernators (South & House, 1967;Saboureau, Laurent & Boissin, 1979). Adipocyte lipolytic activity in the badger is maximal during winter (Chraibi et al, 1982), coinciding with maximal utilization of adipose stores and body mass loss (Neal, 1977;Kruuk & Parish, 1983).…”

Section: Introductionmentioning

confidence: 81%

Overwintering strategies of the badger, Meles meles, at 57 °N

Fowler

Racey

1988

Journal of Zoology

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With 7 figures in the text)Over two eight-month periods (October/November-May) during successive winters (1983/4 and 1984/5), the body temperatures and activity patterns of captive badgers, Meles rneles, living under semi-natural conditions, were studied at 57 "N in Scotland. Temperature-sensitive radio transmitters and automated telemetry systems provided long-term records of body temperatures and times badgers were absent from an artificial sett.Badger body temperatures of 28-34 "C, significantly below euthermic levels, were recorded between October/November and March each winter, with differences between mean daily maxima and minima varying from 1.6 to 8.9 "C. This was associated with a reduction, by up to 90%, in the time that the badgers spent outside their sett in mid-winter. Body temperatures did not show circadian cyclicity, but from February onwards most locomotor activity occurred between 22:OO and 02:OO GMT. The extent to which activity was concentrated around midnight increased with decreasing night length in spring.The body temperatures of one female badger fell to a nadir of 28 "C immediately prior to ovoimplantation. During post-implantation gestation, the body temperature of this female rose steadily, but had reached only 34.6 "C at parturition.Photoperiod correlated closely with seasonal changes in body temperatures and activity levels, and is suggested as the primary synchronizer of seasonal activity and body temperature cycles. Other environmental variables, particularly ambient temperature and snow-cover, appeared to act as modulating influences on these cycles.It is postulated that during the winter, when climatic conditions are responsible for a shortage of food and an increase in heat loss, winter lethargy is an adaptation which enables the European badger to maintain energy balance. Reduced activity and confinement within sheltered setts, together with reduced body temperatures, enable the badgers to rely heavily on energy stored in adipose tissue during the autumn.

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“…High thyroxine utilisation rates have also been suggested to explain the unusually high BMR of the shrew ( Sorex vagrans ) [ 51 ]. In badgers, blood plasma concentrations of thyroxine have previously been shown to fall rapidly to low levels by December until a rise occurs during March [ 52 ]. Thus, a winter depression in thyroxine would correlate with the reduction in metabolic rate seen in the current study.…”

Section: Discussionmentioning

confidence: 99%

Winter Is Coming: Seasonal Variation in Resting Metabolic Rate of the European Badger (Meles meles)

et al. 2015

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Resting metabolic rate (RMR) is a measure of the minimum energy requirements of an animal at rest, and can give an indication of the costs of somatic maintenance. We measured RMR of free-ranging European badgers (Meles meles) to determine whether differences were related to sex, age and season. Badgers were captured in live-traps and placed individually within a metabolic chamber maintained at 20 ± 1°C. Resting metabolic rate was determined using an open-circuit respirometry system. Season was significantly correlated with RMR, but no effects of age or sex were detected. Summer RMR values were significantly higher than winter values (mass-adjusted mean ± standard error: 2366 ± 70 kJ⋅d−1; 1845 ± 109 kJ⋅d−1, respectively), with the percentage difference being 24.7%. While under the influence of anaesthesia, RMR was estimated to be 25.5% lower than the combined average value before administration, and after recovery from anaesthesia. Resting metabolic rate during the autumn and winter was not significantly different to allometric predictions of basal metabolic rate for mustelid species weighing 1 kg or greater, but badgers measured in the summer had values that were higher than predicted. Results suggest that a seasonal reduction in RMR coincides with apparent reductions in physical activity and body temperature as part of the overwintering strategy (‘winter lethargy’) in badgers. This study contributes to an expanding dataset on the ecophysiology of medium-sized carnivores, and emphasises the importance of considering season when making predictions of metabolic rate.

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Seasonal variations of thyroid activity in the adult male badger, (Meles meles L.)

Cited by 22 publications

References 21 publications

Seasonal rhythms of locomotor activity and thyroid function in male badgers(Meles melesL.)

Seasonal rhythms of locomotor activity and thyroid function in male badgers(Meles melesL.)

Overwintering strategies of the badger, Meles meles, at 57 °N

Winter Is Coming: Seasonal Variation in Resting Metabolic Rate of the European Badger (Meles meles)

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