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Activity patterns in mammals: Circadian dominance challenged
David G Hazlerigg1, Nicholas J C Tyler2
1Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway.
Plos Biology
|July 16, 2019
Summary
Mammalian activity patterns are not solely dictated by circadian clocks, as commonly believed. Energy metabolism and feeding behaviors significantly influence daily rhythms across diverse species, challenging the nocturnal rodent model.
Area of Science:
- Chronobiology
- Mammalian Physiology
- Animal Behavior
Background:
- The prevailing circadian paradigm for mammalian physiology and behavior relies heavily on nocturnal rodent models.
- This model overlooks crucial roles of energy metabolism and alimentary functions in shaping activity patterns.
Purpose of the Study:
- To challenge the universal applicability of the nocturnal rodent/human circadian model for mammalian activity patterns.
- To highlight the importance of energy metabolism and feeding in temporal organization.
Main Methods:
- Comparative analysis of activity patterns across diverse mammalian taxa.
- Review of existing literature on circadian rhythms, metabolism, and feeding in mammals.
Main Results:
- Circadian timekeeping is vestigial or significantly different in taxa such as ungulates, microtine rodents, and insectivores.
- Energy metabolism and feeding/digestion are key determinants of activity patterns, not just circadian clocks.
Conclusions:
- The nocturnal rodent/human paradigm is insufficient for understanding the broad spectrum of mammalian activity patterns.
- A more inclusive model incorporating metabolic and digestive factors is needed to explain temporal organization in mammals.
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