METABOLISM AND THERMOREGULATION IN THE FOREST SHREW MYOSOREX VARIUS (SORICIDAE, CROCIDURINAE)

The forest shrew (Myosorex varius) is grouped with the subfamily Croci durinae, but recent allozyme evidence suggests that it is intermediate between the Crocidurinae and the Soricinae. It also exhibits some aty pical morphological features. Because the two subfamilies have differe nt habits and levels of metabolism, we measured activity patterns, met abolism and thermoregulation of M. varius to assess whether its physio logy was consistent with that of the other crocidurines. Metabolic rat e within the thermal neutral zone (29-35 degrees C) averaged 38.9 J g( -1)hr(-1), close to expected levels for a mammal of equivalent size. B ody temperatures were quite variable, ranging from 33.2-38.3 degrees C and were defended at temperatures as low as 6 degrees C by increased heat production. These data suggest that M. varius is a typical crocid urine. In contrast to other crocidurines, however, M. varius did not e nter torpor. They also exhibit differences in their winter activity pa tterns and may be territorial, suggesting that at least in some respec ts M. varius does differ from other crocidurines. (C) 1997 Elsevier Sc ience Inc.