If a mammal drinks large amounts of salt water what will this do to its urinary output?

Due to its evolutionary descent from fresh water fish mammals get rid of excess salt by flushing it out with excess water. (Fresh water fish always had excess fresh water that was in need of getting rid of, so that is the method they developed and mammals inherited.) If a mammal drinks salt water it tries to get rid of the excess salt by excreting excess water and slowly dehydrates itself to death.