1930] MAMMALS OF OREGON 361 



Their fine little squeaking voices are rarely heard except in captiv- 

 ity and close up but evidently are used to indicate their feelings 

 toward each other and the world at large- 



Breeding habits. Adult females have 6 mammae arranged in a 

 double row of 3 each, well back on the lower parts. They are gen- 

 erally given as 2 pairs of inguinal and 1 pair of abdominal, but are 

 so far back and close together as to be sometimes given as 3 pairs 

 of inguinal. The embryos vary from 4 to 8 in number, 6 apparently 

 being normal for adults. Embryos are found in June, July, and 

 August, but probably only one litter of young a year is raised. Little 

 is known of the young after birth, and few naturalists have ever 

 seen a young shrew. 



Food habits. While true insectivores in dentition and habits, 

 the dusky shrews are also fond of any fresh meat and certain kinds 

 of vegetable food. Field examination of their stomachs and the 

 intestinal tracts usually show mainly insect remains, bits of exoskele- 

 ton, legs and other hard parts floating in a mass of soft material that 

 evidently represents the internal organs and fluids of insect bodies, of 

 insect larvae and eggs, or of the soft body parts of worms and other 

 low forms of animal life. Occasionally a stomach will be found well 

 filled with the recently eaten flesh of some small animal with a few 

 hairs that may serve to identify the species, and many of the small 

 rodents caught in traps for specimens by the field collector are found 

 half eaten by these voracious little beasts. To what extent they kill 

 such prey will not be known until someone studies their habits in 

 captivity in an intelligent and systematic manner, but it is probable 

 that their destruction of young rodents in the nests is one of the 

 incentives accounting for their being so often found associated with 

 rodent runways. To some extent they appear to eat plant food, and 

 are often caught in traps set for mice and baited with rolled oats or 

 nuts, the bait being found in the mouths and stomachs of the shrews 

 as evidence of the acceptance of such food. Still more rarely traces 

 of green plants are found in the stomachs, but this is not usual and 

 may be accidental. 



Like all shrews these animals are voracious feeders and die in a 

 short time if food is not available. They do not become fat and do 

 not hibernate, but are active all winter, finding abundance of food 

 in underground burrows and cavities. 



Economic status. On general principles insectivorous animals are 

 supposed to be beneficial in their economic relations to man, but so 

 little is known as to the species and quantities of insects consumed 

 by these shrews that we cannot say whether they protect the trees, 

 grass, or crops in general, nor how much of their food is neutral and 

 of no direct benefit to us. 



SOREX OBSCURUS BAIRDI MEBBIAM 

 BAIED'S DUSKY SHREW 



Sorex bairdi Merriani, North Amer. Fauna No. 10, p. 77, 1895. 



Type. Collected at Astoria, Clatsop County, Oreg., August 2, 1889, by T. S. 

 Palmer. 



.General characters. Larger than typical obscurus, and more uniformly brown 

 above and below. In summer pelage, upper parts rather bright tobacco brown, 

 lower parts but \itt\s lighter, tail scarcely bicolor. Winter pelage not seen. 



