Polyphasic Activity Patterns in Small Mammals

• Published in: Folia Primatologica Vol. 77; no. 1-2; pp. 15 - 26
• Main Author: Halle, Stefan
• Format: Journal Article Conference Proceeding
• Language: English
• Published: The Netherlands Brill 01.01.2006; Karger; S. Karger AG
• Subjects: Adaptation, Physiological; Animal and plant ecology; Animal ethology; Animal, plant and microbial ecology; Animals; Arvicolinae - physiology; Autoecology; Behavior, Animal - physiology; Biological and medical sciences; Biological anthropology; Body Size; Cathemerality; Cellulose; Circadian Rhythm - physiology; Energy Metabolism - physiology; Environment; Environmental conditions; Evolutionary anthropology; Fundamental and applied biological sciences. Psychology; Hunger; Mammalia; Mammals; Primate behaviour; Primate biology; Primates; Primatology; Psychology. Psychoanalysis. Psychiatry; Shrews - physiology; Vertebrata; Cathemerality; Shrews; Ultradian rhythm; Predation; Polyphasic activity; Metabolism; Activity patterns; Voles; Behavioural ecology; Activity; Ecology; Micromammals; Vertebrata; Mammalia; Predation risk
• ISBN: 3805580762; 9783805580762
• ISSN: 0015-5713; 1421-9980
• DOI: 10.1159/000089693

Cathemeral species are routinely active during the day, the night and at twilight. For the majority of species it is advantageous to specialize on the environmental conditions of a particular phase of the 24-hour day, so this rather uncommon type of activity must be a consequence of specific constraints. Good examples are the polyphasic activity patterns found in some small mammals. In shrews, with small body size and extremely high metabolic rate, polyphasic activity represents a simple short-term hunger cycle. In voles the short-term rhythm is triggered by an additional endogenous ultradian clock that interacts with the common circadian system, which probably is functionally related to endosymbiont digestion of cellulose-rich food. The activity bouts of individuals are synchronized on the population level to spread predation risk. As cathemeral species, voles are not specifically adapted to particular light conditions, but they are also not restricted to a particular activity phase. Therefore, the benefits from flexible responses in activity timing to environmental challenges may compensate for the disadvantages of not being specialized.