The metabolic response of the Bradypus sloth to temperature

PeerJ

article

Rebecca Naomi Cliffe¹  David Michael Scantlebury⁴  Sarah Jane Kennedy³  Judy Avey-Arroyo²  Daniel Mindich²  Rory Paul Wilson¹ 

[1] Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University;The Sloth Sanctuary of Costa Rica;Research Center, The Sloth Conservation Foundation;School of Biological Sciences, Institute for Global Food Security, Queen’s University Belfast

关键词: Bradypus;    Energetics;    Arboreal folivore;    Metabolic depression;    Metabolic rate;    Sloth;    Temperature response;   

DOI  :  10.7717/peerj.5600

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.

【 授权许可】

CC BY