system
Given the following post, respond as if you're commenting on Reddit:
human
Why do we need to urinate such large volumes of water, rather than retaining it and drinking less frequently?

If our body needs so much water to function, why do we constantly urinate it out? Could we not retain more of the water, and urinate a smaller amount of more concentrated waste?
gpt
Many desert dwelling mammals do produce smaller volumes of more concentrated urine. However, there is a price paid in energy for that transport. Everything is a balancing act between energy and available resources. 
To an animal that lives in a climate with plentiful water, there is a disadvantage to spending energy concentrating urine for no real gain. When starvation is a bigger danger than thirst, energy conservation wins, when water is the limiting resource, and stillsuits are not available, conservation of every drop is more essential than conserving every calorie of energy.