- We tested whether cortisol: creatinine ratios in mule deer (Odocoileus hemionus) urine in snow accurately predicted the ratios in bladder urine, because accurate estimation of such ratios may provide an important and convenient index to assess mule deer population condition. We conducted 2 experiments using a homogeneous pool of urine from 3 castrated yearling mule deer. In the first experiment, we tested the effects of suspension time over a period of 24 hours by adding urine to snow-filled styrofoam cups. In the second experiment, we tested dilution effects at 0-80% by adding melted snow to pure urine. Suspension time and dilution did not affect urinary cortisol: creatinine, but the power of our tests was low. Further studies are needed before urinary cortisol: creatinine ratios diluted in snow can be considered a reliable index of winter stress in wild animals.