MILTON P. SKINNER 
FIELD NATURALIST 
JERGINS TRUST BUILDING 
CORNER PINE AVENUE AND EAST OCEAN 
LONG BEACH, CALIFORNIA 
July 10, 1930. 
Yr. Aldo Leopold, In Charge, 
Game Survey, 
421 Chemistry Bldg., 
Madison, Wise. 
Dear Mr. Leopold: 
Your letter dated the first has been received. 
It seemed to me that your question was so important that 
I have spent two days looking up my publications and 
notes pertaining to minimum water requirements of various 
mammals.   I am not returning your table, but I am writing 
out my notes.   You can then mark out a table for your- 
self.   All these publications and notes refer to 
mammals in Yellowstone Park.   I have been particular 
to separate my data from my beliefs.  Where either 
heading is omitted,. you will understand that I have 
nothing to say on the subject. 
Publications:   "In winter, they Eprong-horns 
eat snow in preference to hunting up the scarcer open 
water.   When they do seek water, they are as apt to 
do so at noon as at any other time of day."   Skinner, 
M.P. The Prong-horn.     Journal of Mammalogy, Vol 3, 
No 2.   May, 1922.   Page 97.   Belief: Prong-horns 
like water when they can get it easiy, and drink 
daily; 'but they can go without water for two or three 
days without discomfort, if necessary. 
See White-tailed Deer Formerly in the Yellow- 
stone Park, by M.P.Skinner.  Journal of Mammalogy, 
Vol 10, No 2.    May, 1929.   Page 112. 
Notes by M.P.Skinner; unpublished as yet: 
Mountain Sheep; Data: I have seen the same sheep 
drinking on successive days for weeks at a stretch. 
Belief: They drink regularly at least once a day. 
W        Belief: As I seldom see them drinking, I 
t1iiiiikheir dependence on water is largely modified 
by the amount of juices and dew they get with their 
food.    Ata:  They eat snow at frequent intervals 
in winter; at times they search out salty and alkaline 
waters by preference to fresher supplies. 
Mule Deer: Data: They need water regularly and drink 
once or twice each day.   They eat snow in winter. 
1     Appear to prefer cooled hot-spring-water con- 
taining carbonic acid, lime, and other minerals 
Pn:uirrel: At times drink greedily of fresh water. 
M      ear: Belief: While I have seen black bears 
drink greedily in warm weather, I believe that ordinarily 
they get enough water with their food.