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Archive for March 6, 2015

Porcupine Cecum

3-6-15 porcupine2 IMG_5163Your guesses were outstanding – especially “Pinocchio scat” and “petrified baby hippopotamus”– and a couple of readers even nailed it: part of the intestines of a porcupine. (Many of you suggested it might be a black bear’s fecal plug – not a bad guess – though any bear that had to pass something this large when it woke up might decide to hibernate year round.)

Mystery Photo Explanation: A fisher killed and ate a porcupine, choosing not to eat (and leaving behind) a portion of the porcupine’s digestive tract called a cecum – a sac located between the large and small intestine where the cellulose in leaves and bark that a porcupine eats are broken down.

During the warmer seasons of the year, porcupines feed on sugar maple buds, leaves of basswood, aspen and beech saplings, grasses and other herbaceous plants, apples, acorns and beech nuts. In winter, their diet consists mostly of leaves (mainly eastern hemlock in the Northeast), which contain low levels of nutrients and high levels of dietary fiber. Certain mammals and birds possess specific bacteria that secrete enzymes capable of digesting the cellulose in fiber (beavers, hares, rabbits and ruffed grouse come to mind) through the process of fermentation. Because these enzymes work slowly, the digestive tract of a porcupine is very long (26% of a porcupine’s total weight) and the fiber passes through it slowly.

A majority of the bacterial activity in a porcupine’s digestive system takes place in the cecum, which is about the same size as a porcupine’s stomach. Here fermentation turns finely ground woody material into molecules small enough to be absorbed by the porcupine’s body. (A process referred to as “hind gut fermentation.”) Research shows that 16% of a porcupine’s energy requirements are supplied by the porcupine’s cecal fermentation.

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