Winter energy requirements of soricine shrews

The energy requirements of shrews under snow cover have not been determined. This is an expository paper attempting to ascertain the daily energy budget of a soricine in subnivean conditions. By means of extrapolation from past work (Morrison, Ryser & Dawe, 1959; Gebczynski, 1965, 1971), a winter individual of Sorex cinereus (mean weight of 2–6 g) in southern Manitoba has a rather high energy budget at 2oC of about 38‐6 kj or 9‐2kcal per day. It is assumed that winter prey include invertebrates and small mammals, and their biomass and energy content are estimated. Compensatory factors reducing energy needs are considered, i.e. Dehnel's Phenomenon, extended periods in the nest, low population densities and adequate snow cover. We can probably reduce the above figure for a daily energy budget when considering all the above factors, so that about 30 kj are required daily at the mean subnivean temperature of – 4–5oC.