How Do Sea Animals Drink Water?

Yesterday we discussed how fish drink water. In the ocean, the problem isn’t water but salt. Ocean fish are designed with specialized gills that support the kidneys in getting rid of salt accumulations that would otherwise pickle the fish. Obviously, not all animals that live in the ocean have gills. How do sea animals drink water?

Albatrosses and petrels are birds that can spend a year or more in the open ocean, but they need to drink water. Whales and seals also do not have land-based water supplies, and yet, like all mammals, they need water to survive. So how do sea animals drink water when ocean water is salty? God’s design of living creatures always includes unusual equipment to enable them to deal with their environment.

In the case of sea birds, they have a set of salt glands in their heads that connect to the bird’s nostrils. The birds drink seawater, but the glands are so efficient that within three hours, all of the salt is removed through the nostrils.

Whales and other aquatic mammals produce urine that has extremely concentrated salt content. By allowing high salt concentrations in the urine to diffuse into the ocean, the salt never reaches toxic levels inside the animal. An interesting sidelight to this is that the milk of these sea mammals is very low in water content. In that way, they conserve water. Milk from seals has only half the water content of lean hamburger.

Everywhere we look in the natural world, we see that a wonder-working hand has gone before. These marvelous designs are not the product of mindless chance. They show an Intelligence who created with purpose and wisdom. When we realize that ocean water has high salt content, we question, “how do sea animals drink water?” God already took care of that.

In Job 38-40, God challenged Job to advance his understanding of God’s power and wisdom by considering the natural things of creation. When Job questioned God’s wisdom and purpose in his personal struggles, he did not recognize the wisdom shown in creation’s design. We too need to look at what God has done and “know there is a God through the things He has made” (Romans 1:18-20).

— John N. Clayton © 2020

Data from National Wildlife magazine, June/July 1995, pages 30-34.