[Serious] Why defecation?

[John 6IX Breezy]

None of that matters. Give me a good and sufficient reason why God would design wombats to excrete 50% of what they eat when he could just as easily have designed them to metabolize 100% of what they eat.

Boru

This demand just seems very poorly formulated. You've narrowed down on a number without any understanding as to why it occurs; and treat 50% as wrong solely because it isn't 100%. I disagree with that.

Food is only needed to meet the metabolic needs of a given animal; and animals are free to eat whatever they want. The only issue I would have with a digestive system excreting 50% of food is if the metabolic needs of the organism are not being met with this number. In this scenario the animal is starving despite eating sufficient food.

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Edit: I took a second to gather my thoughts; because I think there's just way too much that you're ignoring. But to give just one possible reason why choosing 50% is better than 100% is simply because 100% places extreme restrictions on an animals diet. Overconsumption and underconsumption becomes much more significant when you've given an animal absolutely no metabolic headroom.