Torpor


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torpor

[′tȯr·pər]
(physiology)
The condition in hibernating poikilotherms during winter when body temperature drops in a parallel relation to ambient environmental temperatures.

Torpor

 

a state of sharply decreased life activity that occurs in cold-blooded (poikilothermic) animals as an adaptation for surviving unfavorable environmental conditions, especially insufficient warmth, moisture, and food. In torpor, the animal is immobile and stops eating. Gas exchange and other physiological processes are severely inhibited (see ANABIOSIS).

Winter torpor sets in when the temperature of the environment drops. It is characteristic of animals in the northern and temperate latitudes, including many terrestrial and aquatic invertebrates, fishes, amphibians (frogs, tritons, and toads), and reptiles (lizards, snakes). During winter, some of these animals hide under the bark of trees, under fallen leaves, in tree hollows, in rodent burrows, or under rocks or dig into the ground or moss. Others bury themselves in mud. Animals become torpid at different environmental temperatures. For example, some insects, fishes, and amphibians become torpid, or dormant, at temperatures lower then 10°-15°C, and others, only at 0°C.

The duration of torpor depends, to a considerable extent, on climatic conditions and on the quantity of food products stored in the body in advance. The body temperature of an animal in torpor is almost the same as the environmental temperature and only rarely drops below 0°C. However, the majority of animals subject to torpor are capable of “supercooling”—that is, they will not freeze to death if the temperature drops below 0°C.

Summer torpor, which is far less common than winter torpor, is associated with drought. When a body of water dries up, some fishes (Dipnoi, for example), amphibians, and reptiles become torpid. If the vegetation in their habitat is burned or dried out, some terrestrial snails and reptiles (for example, steppe tortoises) become torpid. In summer torpor, animals either become dehydrated (lose a great deal of water) or hide in moist shelters, such as mud.

Under the effect of low temperatures, some birds may experience a temporary decrease in body temperature and the onset of a state similar to torpor in poikilothermic animals. The study of torpor has great practical significance for devising methods of controlling agricultural pests and the carriers of human diseases.

Hibernation in mammals is analogous to torpor in coldblooded animals. Some scientists use the term “hibernation” to designate the phenomenon of dormancy in both mammals and cold-blooded animals.

References in periodicals archive ?
Torpor use was measured using temperature loggers placed in the nests of the animals, which detected the sharp drop in body temperature occurring during torpor.
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The animals also appear to use torpor when the WEATHER is colder.
During hibernation, mammals undergo repeated cycles of torpor and arousal and several physiological and biochemical parameters are reversed to normal euthermic levels
In vitro studies could determine the comparative susceptibility of bat viruses and nonbat viruses grown in culture to altered and variable thermal regimes typical of the body temperatures of bats during flight, as well as bats in torpor.
Hibernation is a physiological adaptation characterized by entry into torpor, which involves profound decrease in metabolism, heart rate, respiration, and body temperature (a few degrees above the ambient temperature) (Geiser, 2004; Okamoto et al.
CDATA[ The traditional Israeli Religious Zionist mainstream must awaken from its torpor and make its voice heard above that of "enlightened moderates" who have monopolized media coverage.
In British Columbia, male pallid bats select warmer day roosts, minimizing bouts of deep torpor (Rambaldini and Brigham, 2008).
Film star Stephen Dorff (above) 'rests' at leisure, until daughter Elle Fanning shakes him from his drug-fuelled torpor.
Without this snow cover, organisms that rely on freezing themselves to survive winter are at risk of fluctuating temperatures bringing them out of torpor prematurely, only to endure colder conditions later in the season.
A desperate attempt to rouse fans out of their stillgetting-over-the-weekendand-first-day-back-at-work torpor and get them down to the ground?
Peter Bart's column on the perils of blockbuster dependency (Tentpole Torpor Stalls Hollywood's Dream Machine) found readers sympathetic but similarly frustrated about the loss of creativity in the biz's corporate culture.