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Wildlife Wonders

Today is ___________Day!

Instead of me telling you what day it is I want you to try and answer this question.  What animal is an engineer, architect, logger, contractor, carpenter, builder and scuba diver? 

(Please read the a dam fine letter from Stephen Tvedten following an official complaint!

Did you guess correctly?  Yes, it is a beaver!  Today is Beaver Day!

Beavers are super amazing animals!  First of all they are North America’s largest rodent.  Massachusetts biologist, Jim Cardoza ,reported one weighed 93 lbs., but most are 28-75 lbs.

Beavers are nature’s engineers.  By cutting down trees, building dams and flooding areas they are able to create wetlands that provide habitat for a tremendous number of plants, invertebrates and all types of wildlife.  In pre-colonial times it is estimated that there were 60 million, yes 60 MILLION, beavers in North America.  That is a lot of beaver and they basically changed the landscape of America, but with the arrival of Europeans beaver pelts were used as a form of currency and were sought by early trappers for their fur and meat.  Their fur is thick, brown and watertight.  Beavers use the double claw on their webbed hind foot to comb their fur and rub it with an oil secreted from an anal gland to keep it watertight.  They also have glands that secrete castoreum used to mark their territories.  Castoreum is said to smell like vanilla and it is still used in perfume and for about 80 years was a flavoring in food as a replacement for vanilla and in some fruit flavorings such as strawberry and raspberry.  It was also used in liquor.  Are you grossed out now??

Ok, let’s get to some other cool adaptations.  Beavers can remain under water for up to 15 minutes.  They have valves that close off their ears and nostrils.  They can still keep working because their lips close behind their orange incisors.  When eating underwater the back part of the tongue raises and close the passage to the lungs so water doesn’t interfere with breathing. Also, they have a clear membrane that comes over their eyeball to protect it underwater. They are rodents and like other rodents their teeth continuously grow so they have to keep gnawing on things.  The incisors are about 1/4 inch wide and orange in color due to iron  that keeps the enamel strong so they can cut down trees.  There is almost no limit to the size of the tree they can cut down.  It is said a beaver can cut down a 5″ willow in 3 minutes!

Beavers strip the outer bark of the tree to get to the section known as the cambium.  They feed on this along with the leaves and buds.  The branches are also use to create the dams and lodges.  In 1784, explorer David Thompson, reported a beaver dam wide enough for two horses and 1 1/4 mile long.  Beavers favorite foods include aspens, alders, willows and cottonwoods.

Beavers build lodges to live and raise their young in.  The lodges are made of tree branches, stones and mud.  Unlike what you would be led to believe in cartoons beavers do not use their tails to carry mud and pack it down.  They use their front feet to roll the mud and pack it down in place.  The flat tail has scales and is where fat is stored.  The tail has many uses – it acts as a rudder for steering, a prop when they are cutting down trees, a temperature regulator, a rear end balance when carrying heavy trees, and a warning to intruders.  They slap it on the water to scare other animals, including humans, away. The lodge consist of a 6-8 ft. wide, 2 ft. high chamber, a platform above water, , a couple entrances underwater and a “smoke” hole above water for ventilation.  Isn’t that amazing???

Beavers live in the lodge as a family group, or colony, consisting of the breeding pair, and 4-5 offspring including the newborns (kits) and siblings up to two years old.  Beavers are very social and affectionate to one another.  When the young are born in mid-May to early June they have a complete coat of fur, the eyes are open, their incisors are visible and they can walk at 4 days old.  They usually remain in the lodge for a month and when they come out and are swimming if they get tired they will climb on mom’s back for a ride.  Muskrats and otter have been found to live alongside them in their lodges.  At two years old the beavers normally leave the parental lodge and establish their own colonies.  They can travel 5-10 miles, or farther, from their original homes.  Not all beaver build lodges some dig burrows in the banks of rivers where dams are impossible. 

Humans are said to be their worst enemy due to over-trapping. Wolves (out west), bobcats and river otters are their predators, as well. 

Between 1652 – 1657 a fur-trader in Springfield, MA shipped 8,992 beaver pelts.  In the late 18th century, Zadoc Benedict began making hats in Danbury, CT.  According to the CT Historical Society, Danbury was an ideal location for hat making due to its abundant populations of beavers and rabbits for pelts, thickly wooded forests for firewood and an ample supply of water for boiling pelts and running machinery.  By 1809, there were 56 hat shops in Danbury. In the early 1800’s, hatters in Danbury softened the fur by boiling it to make felt and then shaped it.  They shipped the unfinished hats to New York City where they were finished.  Although Danbury led the world in producing hats this was neither good for the beaver nor the workers.  The solution hatters washed animal pelts in contained mercury nitrate.  The exposure to mercury caused “hatter’s shakes” tremors caused by damage to the nervous system.  Although noted in medical literature in 1860 and the factories were monitored in the 1880’s and 1890’s it was not until 1941 that mercury was banned and hydrogen peroxide replaced mercury. 

Beavers have been an integral part of our history. By 1930, they had to be protected since they had been trapped to near extinction.  Beaver were successfully reintroduced in Lenox, MA in 1932.  Beaver harvest today is closely regulated.  Because beaver flood areas, not everyone is a fan of beavers, but we do need to find ways to co-exist!


Tracking and the Art of Seeing by Paul Rezendes

New England Wildlife Habitat , Natural History, and Distribution by Richard M. DeGraaf and Mariko Yamasaki

Native American Stories told by Joseph Bruchac from Keepers of the Earth, Michael J. Cudato and Joseph Bruchac, Gluscabi and the Game Animals

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