system
Given the following post, respond as if you're commenting on Reddit:
human
How can ocean mammals drink the water?
gpt
In general, they don't. While they may take some in on occasion, it's a small amount and is filtered by the kidneys. Most of their dietary water requirement comes from the food they eat. Seals will eat snow sometimes, and manatees (which like in brackish water) will look for fresh water to drink. But purely marine mammals just use their food.

This isn't unique to marine mammals. The kangaroo rat, for example, will not drink water and relies entirely on food. Many desert animals will live on primarily food with little to no fresh water.