DOI: 10.5061/dryad.r7sqv9s90
title: Data from: Body temperature, heart rate, and activity patterns of two boreal homeotherms in winter: homeostasis, allostasis, and ecological coexistence

description: Organisms survive environmental variation by combining homeostatic
 regulation of critical states with allostatic variation of other traits,
 and species differences in these responses can contribute to coexistence
 in temporally-variable environments. In this paper, we simultaneously
 record variation in three functional traits – body temperature (Tb), heart
 rate, and activity - in relation to three forms of environmental variation
 – air temperature (Ta), photoperiod, and experimentally-manipulated
 resource levels – in free-ranging snowshoe hares and North American red
 squirrels to characterize distinctions in homeotherm responses to the
 extreme conditions of northern boreal winters. Hares and squirrels
 differed in the level and precision of Tb regulation, but also in the
 allostatic pathways necessary to maintain thermal homeostasis. Hares
 demonstrated a stronger metabolic pathway (through heart rate variation
 reflective of the thermogenesis), while squirrels demonstrated a stronger
 behavioral pathway (through activity variation that minimizes cold
 exposure). As intermediate-sized, winter-active homeotherms, hares and
 squirrels share many functional attributes, yet, through the integrated
 monitoring of multiple functional traits in response to shared
 environmental variation, our study reveals many pairwise species
 differences in homeostatic and allostatic traits, that both define and are
 defined by the natural history, functional niches, and coexistence of
 sympatric species.
description: Heart rate and body temperature readings were collected every 10
 minutes with implantable dataloggers (surgically implanted in the
 abdomen). Values in the datasheet (HeartRate_Tb_Data.csv) represent
 averages for a given behavioural state (active vs. inactive or in the
 nest), for each phase of the day (dawn, dusk, day, night), for each
 individual.  Activity data was recorded via
 accelerometers set a 1Hz; acceleration across the three axes was recorded
 once per. Behavioural states were determined through species-specific
 hierarchical decision trees. The proportion of each phase spent active
 (Prop_Active in Activity_Data.csv) was calculated by dividing the number
 of seconds spent active (for squirrels = out of the nest; for hares =
 foraging, hopping and sprinting) by the duration of each phase (in
 seconds).  Air temperature was recorded once every 30
 minutes across 3 sites; the value presented in the datasheets is the
 average air temperature across all 3 sites, for the time periods when
 heart rate, body temperature and activity recordings were
 taken. <br>  
description: <strong>HeartRate_Tb_Data.csv</strong><br>
 Columns:<br> Species: identifies either red
 squirrel (Squirrel) or snowshoe hare (Hare)<br> ID: the individual
 ID of a given squirrel and/or hare<br> FieldSeason: whether data was
 collected during winter 2016 (2015-2016) or winter 2017
 (2016-2017)<br> Date: date that the recordings were taken (in
 YYYY-MM-DD format)<br> Phase: phase of the day (Day, Night, Dawn,
 Dusk)<br> BehavioralState: whether a squirrel was in the nest (Nest)
 or out of the nest (Out); or, whether a hare was resting (Rest) or active
 (Active) <br> Food: experimental food supplementation status (Food
 vs. Control)<br> Mass: body mass of the animal (in g)<br> Tb:
 body temperature (in <sup>o</sup>C)<br> HR: heart rate
 (in beats per minute)<br> Ta: air temperature (in
 <sup>o</sup>C)
 <strong>Activity_Data.csv</strong><br>
 Columns:<br> Species: identifies either red
 squirrel (Squirrel) or snowshoe hare (Hare)<br> ID: the individual
 ID of a given squirrel and/or hare<br> FieldSeason: whether data was
 collected during winter 2016 (2015-2016) or winter 2017
 (2016-2017)<br> Date: date that the recordings were taken (in
 YYYY-MM-DD format)<br> Phase: phase of the day (Day, Night, Dawn,
 Dusk)<br> Food: experimental food supplementation status (Food vs.
 Control)<br> Mass: body mass of the animal (in g)<br>
 Prop_Inactive: the proportion of each phase spent inactive<br>
 Prop_Active: the proportion of each phase spent active<br> Ta: air
 temperature (in <sup>o</sup>C)<br>