Do bears hibernate in the woods? Comment on 'Why bears hibernate? Redefining the scaling energetics of hibernation'.
Do bears hibernate in the woods? Comment on 'Why bears hibernate? Redefining the scaling energetics of hibernation'.
复制标题
DOI：
10.1098/rspb.2022.1396
复制
发表时间：
2022-10-12
影响因子：
4.7
通讯作者：
Ruf, Thomas
中科院分区：
文献类型：
--
作者：
Toien, Oivind;Barnes, Brian M.;Ruf, Thomas
Nespolo等人[1]基于体质量的越冬减少对已发表的哺乳动物冬眠期间的能量消耗数据进行了重新汇编，这导致他们得出三个主要结论：(I)冬眠期间的每日能量消耗(DEEHIB)与体质量直接或等长缩放；(Ii)与保持基础代谢率(BMR)相比，冬眠期间的能量节约变为零；在超过75 kg(相对于Dee)的基础代谢率(BMR)下；因此，在熊的大小的冬眠器中不会或几乎不会节省能量；(Iii)DEEHIB的等长缩放是由于每个细胞的最低代谢所固有的。在我们看来，这些数据的选择和汇编方式存在问题。最重要的问题是，DEEHIB并没有与每个物种的经验BMR数据进行比较，而是从一般的异速生长关系中提取出来的。使用特定物种的BMR测量改变了回归线交叉的体质量，因此冬眠不能节省的体重从75公斤增加到超过2250公斤。此外，经验数据表明，冬眠的黑熊(Ursus Americanus)(约.100公斤)将冬眠期间的最低代谢率降低到BMR的25%[2，3]。因此，熊确实在树林中冬眠以节省能量。我们还提出，之前由Heldmaier等人[4]展示的DEEHIB的等距标度对最小细胞新陈代谢有另一种或补充的解释：在冬眠期间用作能量来源的脂肪和其他底物的储存受到身体体积的限制，并与身体质量等距标尺，因此DEEHIB也将与身体质量近似等距标度。由于哺乳动物特定质量的BMR随着体重的减少呈指数增加，冬眠期间的能量节省也会随着身体质量的减少而指数增加，这是通过主动抑制新陈代谢和降低体温来实现的。此外，参考原始文章的表S1，在高体质量时可以获得的数据相对较少，而被比较的较大物种的数据值得额外关注。因此，我们用来自欧洲獾(Meles Meles)体重减轻的DEEHIB数据取代了来自美洲獾的数据，这些数据显示出与黑熊相似的体温下降模式，被认为是冬眠动物。美洲獾每天只有零星的麻木发作。表S1底部列出的黑熊的代谢率节省是错误的，应该是相对于最低代谢率的75%的节省[2]。黑熊的DEEHIB来源于怀孕和未怀孕的黑熊在冬眠中期的体重下降[7]，应该仅限于非怀孕的熊，因为在哺乳期有质量从母猪到幼崽的转移，而雌性在冬眠期间保持体温的恒温水平。
Nespolo et al.[1] provided a recompilation of published data on energy use during mammalian hibernation based on over-winter decreases in body mass, which led them to three main conclusions:(i) daily energy expenditure during hibernation (DEEHIB) scales directly or isometrically with body mass,(ii) energy savings during hibernation become zero compared to remaining at basal metabolic rate (BMR) at body masses above 75 kg (and above 155 kg compared to DEE); thus there would be no or little energy savings in a bear-sized hibernator, and (iii) and that the isometric scaling of DEEHIB is due to an inherent per cell minimum metabolism. In our opinion, there are issues with how these data were selected and compiled. The most important problem is that DEEHIB was not compared to empirical BMR data for each species, but rather drawn from general allometric relationships. Use of species-specific measures of BMR changes the body mass at which regression lines cross and thus where no savings from hibernation can be expected from 75 kg to over 2250kg. Besides, empirical data have demonstrated that hibernating black bears (Ursus americanus)(approx. 100kg) reduce minimum metabolic rate during hibernation to 25% of BMR [2, 3]. Thus, bears indeed hibernate in the woods to save energy.We also suggest that isometric scaling of DEEHIB, shown previously by Heldmaier et al.[4], has an alternative or complementary explanation to minimum cellular metabolism: storage of fat and other substrates used as energy sources during hibernation is limited by body volume and scales isometrically with body mass, and thus DEEHIB will also scale near isometrically with body mass. Since mass-specific BMR increases exponentially with decreasing body mass in mammals, energy savings during hibernation will also increase exponentially as body mass decreases, and this is effected by active suppression of metabolism and decreasing body temperature. In addition, referring to the original article’s table S1, relatively few data are available at high body masses, and the data of the larger species that are compared deserve extra attention. Thus, we replaced data from the American badgers (Taxidea taxus), which only have sporadic bouts of daily torpor [5], with DEEHIB data derived from weight loss in European badgers (Meles Meles) that show a pattern of decreased body temperature resembling that of black bears [6] and are considered to be hibernators. The metabolic rate saving in black bears listed at the bottom of table S1 is quoted incorrectly and should be a 75% saving with respect to minimum metabolic rate [2]. DEEHIB for black bears was derived from weight loss of both pregnant and non-pregnant black bears in mid-hibernation [7] and should be limited to the non-pregnant bears since there is mass transfer from the sow to cubs during lactation, and females maintain euthermic levels of body temperatures during
登录
查看更多内容
影响因子：
2.3
作者：
Hilderbrand, GV;Schwartz, CC;Hanley, TA
通讯作者：
Hanley, TA
影响因子：
56.9
作者：
Toien, Oivind;Blake, John;Barnes, Brian M.
通讯作者：
Barnes, Brian M.
影响因子：
2.6
作者：
Pagano, Anthony M.;Williams, Terrie M.
通讯作者：
Williams, Terrie M.
影响因子：
5.6
作者：
SCHMIDTNIELSEN, K;DAWSON, TJ;CRAWFORD, EC
通讯作者：
CRAWFORD, EC
影响因子：
3.7
作者：
McClune DW;Kostka B;Delahay RJ;Montgomery WI;Marks NJ;Scantlebury DM
通讯作者：
Scantlebury DM