56 



YOSEMITE NATURE NOTES 



From "hltmmtlt of Lakr Ttboe" by R«lrrt T. Ore. Courtety of fubliiher, California Acodtmy of Sciencti. 



SHREW 



Deer and bighorns have no upper in- 

 cisors, but utilize the lowers very well 

 in obtaining food by gripping vegetation 

 against toothless upper "plate" and lips, 

 then wrenching it loose. The greenery 

 then goes into the rear of the mouth 

 where it is ground between large, broad 

 teeth. It then moves to the rumen, a 

 compartment of the stomach which 

 serves as a storage chamber. There the 

 food remains in a half-chewed state un- 

 til the animal is through foraging and 

 finds time in a safe place to give it fur- 

 ther attention. It is then brought up in 

 cuds, chewed and reswallowed for thor- 

 ough digestion. 



The system of classification of mam- 

 mals progresses downward from the or- 

 ders through lesser groups having closer 

 ties in structural relationship, such as 

 families, divided in turn into genera 

 (singular genus), species and subspecies. 

 Such divisions are indicated in the check- 

 list (see p. 104). 



A discussion of the characters delineat- 

 ing these lesser divisions seems entirely 

 beyond the limits of a work of this na- 

 ture. However, it should be explained 

 that the scientific names of the various 

 species contain at least two parts, the 

 first of which is the genus, the second 

 the species, and, where applicable, a 

 third, the subspecies. 



Subspecies, and in most cases, species, 

 are based on comparatively minor differ- 

 ences in color, size, or structure of the 

 skull and teeth and require the dead speci- 

 men in hand for final determination. Ob- 

 viously such characters will not be read- 

 ily observed in the park, where the wild- 

 life is protected by law against moles- 

 tation in any form. 



Perhaps some concept of the nature of 

 a scientific name can be gained by con- 

 sideration of an artificial case, a hypo- 

 thetical man whose name is John Adam 

 Smith. Written as a scientific -name, this 

 would be "Smith John Adam," latinized, 

 of course. Smith may be compared to 

 generic name, John the specific name, and 

 Adam the subspecific, though technically, 

 the example is not truly analogous. 



There is a tendency on the part of 

 mammalogists to use common names for 

 species, but not for subspecies since the 

 latter cannot usually be distinguished in 

 the field, except sometimes on the basis 

 of locality, correlated with its known 

 range. Twenty years of experience in ed- 

 ucational work have taught me that the 

 layman wants common names for the 

 different forms. Since well-established 

 vernacular names for most Yosemite 

 mammals have existed in the literature 

 for many years, I have used them in 

 this work wherever they were available. 



