Annual Biological Clocks

Pengelley, Eric T.; Asmundson, Sally J.

doi:10.1038/scientificamerican0471-72

Cited by 24 publications

(9 citation statements)

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“…The variations may be connected with an endogenous clock mechanism. Pengelley and Asmundson (1971) found an endogenous circannual clock in hibernating animals and suggested the possibility of a similar mechanism acting in man. If this is the case environmental factors, such as light and dark may synchronize the clock and are working as time-keepers only.…”

Section: Discussionmentioning

confidence: 95%

Seasonal variations of congenital dislocation of the hip

Cohen

1971

Journal of Interdisiplinary Cycle Research

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Section: Discussionmentioning

confidence: 95%

Seasonal variations of congenital dislocation of the hip

Cohen

1971

Journal of Interdisiplinary Cycle Research

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“…This restlessness struck Brewster as being quite similar to the preliminary restlessness that wild Robins show before migration commences (i.e., "migratory restlessness"). Since many birds show migratory restlessness when maintained in captivity during their normal migration season (Eyster, 1954;Palmgren, 1938;Pengelley & Asmundson, 1971;Yokoyama & Farner, 1978), captive Robins might be expected to similarly display "roosttime restlessness" during that time of day when they would normally be heading roostward.…”

Section: Roosttime Restlessness In Captive American Robins (Turdus MImentioning

confidence: 99%

Roosttime restlessness in captive American Robins (Turdus migratorius)

Eiserer

1979

Animal Learning & Behavior

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“…These data, together with the observations on the restricted and very similar moulting periods found in the eld and the laboratory, suggest that moulting in C. robustus cray sh may be under the control of a circannual endogenous timing mechanism. Circannual rhythms have been well documented during classic studies in ground squirrels (Pengelley & Asmundson, 1971) and birds (Gwinner, 1986a, b;Gwinner & Dittami, 1990). Endogenous, circannual reproductive cycles have also been observed in several sh species, including the threespine stickleback, Gasterosteus aculeatus Linnaeus, 1758 (cf.…”

Section: Discussionmentioning

confidence: 90%

“…Circannual clocks are very useful for animals which must avoid or minimize exposure to the harshest seasonal conditions of their natural environments (Pengelley & Asmundson, 1971). Northern cray sh, such as C. robustus, have to cope with a reduced food supply and very low water temperatures from the late fall until the spring.…”

Section: Discussionmentioning

confidence: 99%

Observations on the Timing of Moulting Events in the Crayfish Cambarus Robustus Girard, 1852 (Decapoda, Cambaridae)

Guiașu¹,

Dunham²

2001

Crustac

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Cambarus robustus cray sh kept and monitored under constant summer-like photoperiod and temperature conditions in the laboratory did not moult during the winter months. The timing of the moulting events in the laboratory closely matched the timing of the corresponding types of moults in the eld for adult Form I and Form II males, adult females, and juveniles of both sexes. The juveniles moulted during a less restricted period of time than the adults. The Form I to II adult male moults occurred only in the late fall, during a very narrow period. There is preliminary evidence that the timing of moulting in this northern, surface water cray sh species is governed by an endogenous circannual rhythm. This endogenous mechanism is capable of regulating the moulting cycle in C. robustus for long periods of time, even in the absence of any changes in external factors such as water temperature and photoperiod. Such a circannual endogenous rhythm would allow the cray sh to anticipate and prepare, both physiologically and behaviourally, for certain upcoming, predictable seasonal changes in the environment, such as the arrival of winter. Very large, and, presumably, very old individuals of this cray sh species can still moult successfully. The maximum life span of C. robustus may be greater than previous estimates have indicated. RÉSUMÉ

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Annual Biological Clocks

Cited by 24 publications

References 0 publications

Seasonal variations of congenital dislocation of the hip

Seasonal variations of congenital dislocation of the hip

Roosttime restlessness in captive American Robins (Turdus migratorius)

Observations on the Timing of Moulting Events in the Crayfish Cambarus Robustus Girard, 1852 (Decapoda, Cambaridae)

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