An online resource based on the award-winning nature guide

Animal Diets

White-tailed Deer Scraping Bark

3-3-15  deer scraping2IMG_0490During the winter, white-tailed deer browse on the twigs, buds and bark of trees. Deer have incisors in the front of their bottom jaw, but none in the front of their top jaw, just a hard palate. They grip the bark with their bottom front incisors and scrape their jaw upwards, leaving behind grooves the width of their bottom incisors. Often there are frayed ends of bark at the top end of the groove, due to the deer having to use its hard palate and incisors, rather than two sets of incisors, to separate the bark from the tree. Favorite trees include red and striped maples, oaks, poplar, pines, hemlock, arborvitae and balsam fir.

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Coyotes Feeding on Deer Carcasses

12-22-14 deer carcass 394Ninety percent of a coyote’s diet is animal matter, including creatures as varied as meadow voles, mice, muskrats, raccoons, beetles and grasshoppers — basically, anything it can outrun. Coyotes have the reputation as major predators of deer. While research confirms that deer (and rabbits) comprise a good portion of a coyote’s diet in the Northeast, the majority of the deer that coyotes consume is scavenged as carrion (see photo). Because they cannot move as fast as adult deer, fawns are more vulnerable to coyote predation.

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How Beavers Digest Cellulose

12-26-14 beaver sign 125Some beavers are still managing to find openings in their ponds which give them access to fresh cambium, the soft layer of wood just under the bark of a tree. Cambium contains a lot of cellulose, in addition to starches and sugars. Like all herbivores, beavers do not possess enzymes that are capable of breaking down the large cellulose molecules (cellulases). In their place, beavers employ micro-organisms, such as bacteria, that can break down cellulose.

These bacteria are located in a pouch called a cecum, located at the beginning of the large intestine. (Ruminants such as moose and deer have rumens in place of ceca.) Colonies of these microorganisms in a beaver’s intestines digest up to 30% of the cellulose from the woody material that it eats. Further nutrients are recovered in the form of fecal pellets that the beaver re-ingests.

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Muskrats Enjoying Last Days Above Ice

12-22-14  MUSKRAT IMG_3496Muskrats and beavers are eking out the last few days that they will spend above the ice for perhaps several months. Fortunately for muskrats, they can hold their breath and remain under water for up to 20 minutes, time enough to get from one unfrozen patch of water to another. Once the ice freezes completely, muskrats will use ‘push-ups’ or ‘breathers’ as resting places and breathing holes — masses of vegetation collected from underwater and pushed up through cracks or holes in the ice.

Throughout the year muskrats eat the roots and stems of a number of aquatic plants as well as crayfish, frogs, turtles and other prey, when available. Unlike beavers, muskrats don’t store food for the winter, but forage for vegetation (see green plants on ice). Sometimes muskrats will feed from the winter food supply piles gathered by beavers. They have also been known to use the walls of their own lodge as food.

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Cow Moose Bulking Up for Winter

cow moose head 461


Moose Gaining Fat Reserves

9-10-14  moose standing in water 277Being an ardent admirer of moose, I am devoting today’s post as well as the next two posts to the largest member of the deer family. Even if it weren’t seven to ten feet long and didn’t weigh over a thousand pounds, a moose would be an impressive mammal, with its high, humped shoulders, broad, pendulous muzzle and long, coarse hair.

Moose are voracious eaters, consuming roughly 44 pounds of plant material a day. In the winter their diet, mainly the bark of woody plants, provides only about 70% of the energy they need to survive. Thus, during the spring and summer they spend up to 12 hours a day foraging, often for aquatic plants, and acquire more than 200% of the energy they need. Hundreds of pounds are gained, with the excess stored as fat reserves for the coming months. Even so, moose lose up to 20% of their weight over the winter. (Thanks to all who wished me happy recharging!)

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Black Bear Scats Reveal Diet

8-25-14  black bear blueberry scat 062Black Bears are eating heavily now, in preparation for the coming winter when they will not eat or drink for several months. Some of what goes in must come out, however, and it can tell you a lot about the diet of an animal. Black bear scats typically weigh ½ to 1 pound or more. They have different shapes and consistencies, depending on what the bear has eaten. Black bear scats may be tubular or loose, depending on the amount of moisture in the food that the bear ate. Scat from succulent vegetation or berries is typically loose. Interestingly, black bear scats do not have an unpleasant smell if the bears ate only fruit, nuts, acorns, or vegetation — they smell like a slightly fermented version of whatever the bear ate.

At this time of year, Blackberries, Wild Sarsaparilla fruit and Blueberries are ripe and favored by bears. You can determine what a bear has been eating by the shape and size of the seeds in its scat. (A bear’s scat can consist of just one type of fruit if there is an ample supply of that fruit.) Wild Sarsaparilla seeds are crescent shaped, Blueberry seeds are tiny and sand-like, and Blackberry seeds are larger than Blueberry seeds. Blueberry scat (pictured) usually includes whole berries that were not soft and ripe enough to be broken up in the bear’s stomach. Bears hardly stop to chew berries. Instead, they swallow them whole and let the muscular, gizzard-like section of their stomach grind the pulp off the seeds. (Thanks to Jeannie Killam for photo op.)

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