Ureotellic... because. 1.Marine mammals aren't osmoconformers; they're hypotonic in marine environments. They need to conserve water. Urea can be eliminated with less water loss than ammonia.2.they are the progeny of terrestrial animals......

Whale: Ureaotelic or Ammoniotelic?

Whales, as marine mammals, have evolved unique physiological adaptations to their aquatic environment. One of the key aspects of their physiology is how they excrete nitrogenous waste, which can be either in the form of ammonia, urea, or uric acid. In the case of whales, they are primarily ureaotelic, meaning they excrete waste predominantly in the form of urea. However, it is important to note that they also possess the ability to excrete some amount of ammonia when necessary.

Ureaotelism in Whales
Whales are ureaotelic, which means their primary mode of nitrogenous waste excretion is through the synthesis and excretion of urea. Urea is less toxic than ammonia and requires less water for its elimination. This is advantageous for marine animals like whales, as they have limited access to freshwater and need to conserve water as much as possible. Urea is produced in the liver through the conversion of ammonia, and it is then transported to the kidneys for excretion. The kidneys filter the blood, removing waste products like urea and reabsorbing essential substances before excreting the concentrated urea in the form of urine.

Ammoniotelism in Whales
While whales are primarily ureaotelic, they also possess the ability to excrete ammonia when necessary. In certain circumstances, such as during periods of fasting or extreme metabolic demands, whales may produce and excrete ammonia as a means to eliminate excess nitrogenous waste. Ammonia is highly toxic and requires large amounts of water for its excretion. Therefore, in most situations, the production of ammonia is minimized to conserve water.

Adaptation and Conservation of Water
Being ureaotelic allows whales to conserve water more effectively than ammoniotelic animals. By converting ammonia into urea, whales can excrete waste products without losing excessive amounts of water. This adaptation is crucial for their survival in the marine environment where freshwater sources are scarce. Additionally, whales have highly efficient kidneys that can concentrate urine, further reducing water loss.

Conclusion
In conclusion, whales are primarily ureaotelic, excreting waste in the form of urea to conserve water. However, they also possess the ability to excrete ammonia when necessary, such as during periods of fasting or high metabolic demands. This adaptability allows whales to maintain nitrogen balance while minimizing water loss in their marine habitat.