The bears’ long dormancy poses other physiological problems. For one, bears do not expel waste for the entire seven months. Most animals would be dead from urea poisoning, but bears’ kidney function barely (or should it be bearly?) budges. It’s unclear how, but apparently bears recycle the by-products of protein breakdown into new proteins and amino acids directly in the blood stream, bypassing urea formation. One speculation is that urea actually is briefly formed but immediately secreted into the gut where bacteria convert it into CO2 and ammonia. These are then exhaled and reabsorbed for processing into new proteins.
Posted on: Thu, 22 Jan 2015 09:48:00 +0000
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