A deer cannot tell if urine is from a human but it can tell if the urine is from a meat eater. With a temp of 72 degree's a deer can tell the urine is from a red meat eater for about an hour.The higher the temp is the shorter amount of time a deer can identify that the urine is from a meat eater and the lower the temp is below 72 degrees the longer a deer can do so. As soon as urine hits the air the molecules in the urine is being broken down. Once urine is about 3-4 hours old (at the longest) a whitetail cannot determine whether urine is from another deer or a hippo. Pike