The nature and potential thermoregulatory benefits of the heat increment of feeding (HIF) were investigated in short-tailed shrews (Blarina brevicauda). At thermoneutrality, the postprandial rate of oxygen consumption ([Formula: see text]O2) of shrews increased by an average of 18% beyond fasting levels for ca. 2 h following the consumption of 3.5 g of earthworms. Over the same period, body temperature increased by an average of 0.6 °C. The digesta-retention time calculated from nickel alloy tracer excretion rates (168.1 ± 11.4 min (mean ± SE); n = 7) exceeded the duration of HIF (117.5 ± 10.4 min; n = 6) by 43%. This finding suggests that the mechanical costs of feeding may be a relatively mi nor component of HIF in this species. Regression of resting [Formula: see text]O2 on ambient temperature (Ta) below thermo neutrality yielded similar slopes (P = 0.71) and intercepts (P = 0.33) for fed and fasted animals, suggesting that HIF substitutes, at least partially, for facultative thermogenesis at low Ta. We found no evidence that HIF enhanced microclimate warming of an insulated, open-flow metabolic chamber occupied by recently fed shrews. Occupancy of this chamber by shrews increased microclimate Ta from 5 to 9.09.5 °C regardless of their nutritional status.
Reassortment Between Divergent Strains of Camp Ripley Virus (Hantaviridae) in the Northern Short-Tailed Shrew (Blarina brevicauda)
