You may have never thought about this question, but how do whales get water? Ocean water turns out to be too salty for the whale, so the whale gets most of its water from the food it eats, such as from fish, krill and plankton. However, a lot of the water the what gets is from its fat, for when fat is broken down, it produces water—which is sometimes referred to as metabolic water. One of the reasons the whale is the fattest animal in the world is that it has substantial water needs. The observation that fat serves as a water source was instrumental in the discovery that dehydration is a stimulus to gain fat.
References
- Johnson, R.J., Stenvinkel, P., Jensen, T., Lanaspa, M.A., Roncal, C., Song, Z., Bankir, L. and Sanchez-Lozada, L.G. (2016) Metabolic and Kidney Diseases in the Setting of Climate Change, Water Shortage, and Survival Factors. J Am Soc Nephrol 27: 2247-2256.
- Ortiz, R.M. (2001) Osmoregulation in marine mammals. J Exp Biol 204: 1831-1844.