title: Embracing heterothermic diversity: non-stationary waveform analysis of temperature variation in endotherms.
abstract: Recent research is revealing incredible diversity in the thermoregulatory patterns of wild and captive endotherms. As a result of these findings, classic thermoregulatory categories of 'homeothermy', 'daily heterothermy', and 'hibernation' are becoming harder to delineate, impeding our understanding of the physiological and evolutionary significance of variation within and around these categories. However, we lack a generalized analytical approach for evaluating and comparing the complex and diversified nature of the full breadth of heterothermy expressed by individuals, populations, and species. Here we propose a new approach that decomposes body temperature time series into three inherent properties-waveform, amplitude, and period-using a non-stationary technique that accommodates the temporal variability of body temperature patterns. This approach quantifies circadian and seasonal variation in thermoregulatory patterns, and uses the distribution of observed thermoregulatory patterns as a basis for intra- and inter-specific comparisons. We analyse body temperature time series from multiple species, including classical hibernators, tropical heterotherms, and homeotherms, to highlight the approach's general usefulness and the major axes of thermoregulatory variation that it reveals.
authors.affiliation: School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA. danielle.l.levesque@maine.edu.
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Levesque
authors.affiliation: Natural Resource Sciences, McGill University, Macdonald Campus, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada.
authors.forename: Allyson K
authors.initials: AK
authors.lastname: Menzies
authors.affiliation: Natural Resource Sciences, McGill University, Macdonald Campus, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada.
authors.forename: Manuelle
authors.initials: M
authors.lastname: Landry-Cuerrier
authors.affiliation: Quebec Centre for Biodiversity Science, McGill University, Montreal, QC, H3A 1B1, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Larocque
authors.affiliation: Natural Resource Sciences, McGill University, Macdonald Campus, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada.
authors.forename: Murray M
authors.initials: MM
authors.lastname: Humphries
mesh_terms: D000818:Animals; D001831:Body Temperature; D001833:Body Temperature Regulation; D000073566:Eutheria / Q000502:physiology*; D012621:Seasons
keywords: Additive quantile regression; Body temperature; Endothermy; Heterothermy; Hibernation; Homeothermy; Thermoregulation; Torpor