Zoologists know that marine mammals, such as seals, dolphins, manatees, and whales, occasionally drink seawater, but they don't know how often they do so. However, these animals have other alternatives to get their daily ration of water. This, for example, is present in the food they eat . Remember that the vital element is one of the by-products of the metabolism of fats and carbohydrates.
The salt content in the blood of these marine mammals is three times less than in seawater, a concentration similar to that of their terrestrial relatives or any other vertebrate. The kidney of these mammals is specially adapted to collect as much salt as possible and eliminate it through the urine. Thus, for example, sea lion pee is 2.5 times saltier than sea water. Other strategies that these mammals follow are to avoid excessively salty foods and drink fresh water whenever they can.
