Milk composition, gas exchange, and energy intake in food were measured in whitetoothed shrews, Crocidura russula monacha, in lactating females (LF) and in simultaneously lactating and pregnant females (LPF). Milk contained 51.2% ± 11.3 SD solids and 9.4% ± 1.0 SDproteins. Milk fat increased from 28.5% ± 0. 46 SD on day 2 of lactation to 42.6% ± 3.5 SD on day 20. Lactose decreasedfrom 3%-8% during the first week of lactation to 2%-4% at the end. Energy content of milk paralleled fat concentration, increasing from 14.86 kJ. g⁻¹ + 0. 4 SD to 17.92 kJ. g⁻¹ ± 1.04 SD. Mass-specific oxygen consumption rate (Mspo₂) of the LF reached apeak value of 3. 68 mL. (g . h)⁻¹ ± 0.58 SD on days 6-8 of lactation, then declined to the nonreproductive value on day 16 (2. 48 mL. [g . h]⁻¹). The Mspo₂ of the LPF remained unchanged throughout lactation at 2. 75 mL. (g . h)⁻¹ ± 0.47 SD. Energy intake in food in both LF and LPF increased daily depending on litter size. In a onepup litter it increased from 31.4 kJ. d⁻¹ ± 4.4 SD to 62.3 kJ. d⁻¹ ± 11.2 SD on day 10, whereas in a four-pup litter it increased from 53.0 kJ. d⁻¹ ± 7.5 SD to 119.3 kJ . d⁻¹ ± 19.2 SD on day 10. The milk with moderate protein and high fat content suits the fast growth rate and heat loss of the pups. Although lactation imposes a severe energy load on the LF, this burden is mainly expressed by the up to fivefold increase in energy intake in food where Mspo₂ increases only up to 1.5 times the normal value. The energy requirements of simultaneous lactation and pregnancy are not simple additives. They seem to overlap partially and thus are energetically less demanding

Body mass (BM), oxygen consumption, and energetic food intake were measured in females of the white-toothed shrew, Crocidura russula monacha, during the gestation period of about 28 days. Maternal BM increased by 34% from the initial BM of 8.53 g ± 1.29 SD. This increase is almost entirely attributed to embryonic mass of 1.0 g ± 0.23 SD per pup (litter size = one to four pups). Mass-specific O₂ consumption throughout gestation was 3.24 ml O₂ ·(g·h)⁻¹ ± 0.17 SD, which is 24% higher than that of the nulliparous females. Energetic intake in food increased from 23.68 kJ· day⁻¹ ± 2.51 SD during the first days to 34.35 kJ ·day⁻¹ ¹ 0.88 SD during the last days of gestation. Nonreproductive females consumed 26.48 kJ · day⁻¹ ± 2.68 SD. Gestation duration is longer than predicted for eutherian mammals of this BM, and within this period the major BM changes and energetic intake occur during the last 2 wk. This presumably enables the main energetic effort to be directed toward lactation during the first 2 wk of gestation. Such time partitioning may be necessary for a small mammal that exhibits a postpartum estrus in order to be able to cope with the already high energetic demands of the nulliparous maintenance.

Specific O2 consumption (Ṁo2) and body temperature (Tb) were studied in the white-toothed shrew Crocidura russula monacha. Ṁo2 and Tb oscillate almost in parallel with a frequency of 4.9–17.1·h⁻¹ and deviation from minimal values of 0.37–0.80 C and 0.40–0.96 ml STPD·(g·h)⁻¹, respectively, depending on ambient temperature (Ta). Minimal Tb changes with Ta from 33.75 C at Ta = 17 C to 37.60 C at Ta = 37 C. The minimal Ṁo2 in the thermoneutral zone (TNZ: 28-36 C) is 2.55 ml STPD·(g·h)⁻¹ ± 0.56 SD. Mean Tb in the TNZ is 36.40 C ± 1.2 SD. The minimal heat transfer constant is 0.414 ml O2·(g·h·C)⁻¹. The adjustment of minimal Tb to different Ta's and the parallel short-term oscillations of both Tb and Ṁo2 seem to be advantageous for this small mammal where energy saving is so important. The oscillations represent a distinct non-steady-state homeostatic pattern rather than an erratic nervous and restless character.

Les animaux attribues a Crocidura russula gueldenstaedti et/ou C. r. monacha en Turquie, Chypre et Israel appartenant en fait au taxon C. suaveolens Pallas 1811

Etude menee dans la plaine cotiere meridionale au cours de nov. 1977 et sept. 1979 (methode de capture-marquage-recapture)

Analysis of records of a bank vole breeding colony suggests that fertility is high immediately post partum, declines during established lactation and rises after weaning of young. Mating tests with lactating females and females whose young had been removed at birth showed that receptivity is reduced during lactation, although amongst the females which did mate there was no difference between lactating and non-lactating animals in the proportion which produced litters. However, average size of litters at birth was significantly larger for the lactating than for the non-lactating females. There is some evidence suggesting that this difference may arise after ovulation has occurred. Virgin females were no more receptive or fertile than lactating females.

The total number of corpora lutea developed in the left and right overies of 170 white-toothed shrews (Crocidura russula monacha) differed significantly, showing a functional dominance of the left ovary. Blastocytes were equally distributed in both uterine horns.

Investigation of bank voles (Clethrionomys glareolus) from the field led Brambell & Rowlands (1936) to conclude that in this species ovulation occurs spontaneously during an oestrous cycle similar to that of the mouse. However, under laboratory conditions it has been shown that in several microtine rodents (e.g. Microtus spp. and Clethrionomys glareolus) ovulation is induced by copulation (Breed, 1967; Richmond & Conaway, 1969; Clarke, Clulow & Greig, 1970; Clulow & Mallory, 1970; Cross, 1972; Gray, Davis, Zerylnick & Dewsbury, 1974). The aim of the present work was to investigate whether ovulation in the bank vole can be induced by stimuli from males other than those provided by coitus.

In common white-toothed shrews, the vaginal smear was an inadequate indicator of receptivity. Nucleated epithelial cells usually predominated and most matings took place when the smear was of this type. Cornified cells in the smear in infrequent. Mating tests showed that virgin females 2 to 4 months old, were unreceptive for extended periods. Willingness to mate increased gradually with the age of the female. Females were receptive throughout pregnancy, suggesting a continuous secretion of oestrogen during gestation. There was a post-partum oestrus whether or not the young of the litter were being suckled, and an oestrus at the end of lactation. During mid-lactation, females were in a state of low receptivity, whether or not they were suckling.