Mammals can hear well, because of the 3 middle ear bones mentioned above. Dogs have acute hearing. These species bounce a sound wave off an object. They, for example bats, use a high frequency sound to detect small objects like insects. Color vision is less well developed in mammals than in reptiles and birds.
Many mammals have no color perception.
V. Excretion and Osmoregulation Excretion of urine in mammals is a major source of water loss. It takes considerable water to wash urea from the body. Some mammals are well adapted to living in very dry environments. The Kangaroo rat is a good example. This is a very general topic.