which these animals haul out are truly desert islands, as dry and nearly as hot as the nearby mainland. These sea lions have no access to fresh water. The question naturally arises, do they drink sea water? If they drink sea water, they must somehow get rid of the salts. If they do not, then they must somehow get rid of the large amount of fixed nitrogen which their carnivorous diet yields as a waste product. If they eat invertebrates such as squid, then they must excrete not only the nitrogen wastes but also the excess salts, for, unlike fish, invertebrates are commonly thought to have a salt concentration in the body fluids which is similar to that of sea water.