Think of the beaver's digestive organ system. Explain its overall role. List several of the organs in this system, describe how each functions, and outline how the organs work together to carry out the role of the organ system.
Beavers are mammals. Mammals cannot utilize the cellulose found in trees, at least not directly. But beavers eat a lot of bark and wood--how do they obtain nourishment? The answer is that they use the same indirect methods that cows and other ruminants do, though they don't have a huge fermentation vat (the rumen), that cows do. The beaver has bacteria living in its digestive tract that DO eat the cellulose; the beaver then digests the bacteria, obtaining nutrition that way. They also have an adaptation common in animals such as rabbits--they eat their food twice. The food passes through the digestive tract, where it picks up the bacteria. The beaver then eats the food for a second time. So, gross, yes, but the beaver eats its poop.
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