DOI: 10.5061/dryad.tdz08kq52
title: Squamate metabolic rates decrease in winter beyond the effect of temperature

description: The reptilian form of hibernation (brumation) is much less studied than
 its mammalian and insect equivalents. Hibernation and brumation share some
 basic features but may differ in others. Evidence for hypometabolism in
 brumating reptiles beyond the effect of temperature is sporadic and often
 ignored. We calculated the standard metabolic rates (SMR, oxygen uptake
 during inactivity), in winter and/or summer, of 156 individuals
 representing 59 species of Israeli squamates across all 17 local families.
 For 32 species, we measured the same individuals during both seasons.
  We measured gas exchange continuously in a dark metabolic
 chamber, under the average January high and low temperatures (20°C and
 12°C), during daytime and nighttime. We examined how SMR changes with
 season, biome, body size, temperature, and time of day, using phylogenetic
 mixed models. Metabolic rates increased at sunrise in the diurnal species,
 despite no light or other external cues, while in nocturnal species the
 metabolic rates did not increase. Cathemeral species shifted from a
 diurnal-like diel pattern in winter to a nocturnal-like pattern in summer.
 Regardless of season, Mediterranean species SMRs were 30% higher than
 similar-sized desert species. Summer SMR of all species together scaled
 with body size with an exponent of 0.84 but dropped to 0.71 during
 brumation. Individuals measured during both seasons decreased their SMR
 between summer and winter by 47%, on average, at 20°C and by 70%
 at 12°C. Q10 was 1.75 times higher in winter than in summer, possibly
 indicating an active suppression of metabolic processes under cold
 temperatures. Our results challenge the commonly held perception that
 squamate physiology is mainly shaped by temperature, with little role for
 intrinsic metabolic regulation. The patterns we describe indicate that
 seasonal, diel, and geographic factors can trigger remarkable shifts in
 metabolism across squamate species.
description: # Squamate metabolic rates decrease in winter beyond the effect of
 temperature Dubiner, Shahar; Jamison, Simon; Meiri, Shai; Levin, Eran.
 (2023). Squamate metabolic rates decrease in winter beyond the effect of
 temperature [Dataset]. Dryad. https://doi.org/10.5061/dryad.tdz08kq52.
 Tables 1-4 show the data used for all analyses in the paper. * Table 1:
 Respirometric measurement results for the individuals measured during both
 seasons. * Table 2: Respirometric measurement results for all individuals
 measured in this study at 20°C. * Table 3: Respirometric measurement
 results for all individuals measured in this study at 12°C. * SMR =
 standard metabolic rate, given as ml O<sub>2</sub> / hour.
 Values are the geometric mean for all n individuals of the species. * Mass
 is in grams (the geometric mean for all n individuals of the species). *
 Table 4: Daily changes in the resting metabolic rate of the 32 individuals
 measured during both seasons. * "Value" is the mean normalized
 (mean=0, SD=1) resting metabolic rate at 12°C calculated from
 CO<sub>2</sub> production for each of the categories
 (diurnal/nocturnal/cathemeral) divided into 1-hour segments. * Statistics
 are comparisons of each segment to the segment with the lowest value.