Beavers


Beavers



Beaver

McLean County, North Dakota

April 19, 2020



Beavers are known for their natural trait of building dams on rivers and streams, and building their homes (known as "lodges") in the resulting pond. Beavers also build canals to float building materials that are difficult to haul over land.  They use powerful front teeth to cut trees and other plants that they use both for building and for food. In the absence of existing ponds, beavers must construct dams before building their lodges. First, they place vertical poles, then fill between the poles with a crisscross of horizontally placed branches. They fill in the gaps between the branches with a combination of weeds and mud until the dam impounds sufficient water to surround the lodge. 


The beaver works as a keystone species in an ecosystem by creating wetlands that are used by many other species. Next to humans, no other animal appears to do more to shape its landscape.


https://en.wikipedia.org/wiki/Beaver


Beavers

McLean County, North Dakota

April 19, 2020


The basic units of beaver social organization are families consisting of an adult male and adult female in a monogamous pair and their kits and yearlings.  Beaver families can have as many as ten members in addition to the monogamous pair. Groups this size or close to this size build more lodges to live in while smaller families usually need only one.  However, large families in the Northern Hemisphere have been recorded living in one lodge. Beaver pairs mate for life; however, if a beaver's mate dies, it will partner with another one.  In addition to being monogamous, both the male and female take part in raising offspring. They also both mark and defend the territory and build and repair the dam and lodge.  When young are born, they spend their first month in the lodge and their mother is the primary caretaker while their father maintains the territory. In the time after they leave the lodge for the first time, yearlings will help their parents build food caches in the fall and repair dams and lodges. Still, adults do the majority of the work and young beavers help their parents for reasons based on natural selection rather than kin selection. They are dependent on them for food and for learning life skills.  Young beavers spend most of their time playing but also copy their parents' behavior. However, while copying behavior helps imprint life skills in young beavers, it is not necessarily immediately beneficial for parents as the young beaver do not perform the tasks as well as the parents.


https://en.wikipedia.org/wiki/Beaver



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020



Beaver

McLean County, North Dakota

April 19, 2020


A beaver's teeth grow continuously so they will not be worn down by chewing on wood.  Their four incisors are composed of hard orange enamel on the front and a softer dentin on the back. The chisel-like ends of incisors are maintained by their self-sharpening wear pattern. The enamel in a beaver's incisors contains iron and is more resistant to acid than enamel in the teeth of other mammals.


https://en.wikipedia.org/wiki/Beaver



Beaver Dam

Theodore Roosevelt National Park, North Dakota

March 28, 2020


This beaver dam has logs and sticks at the base and evergreen branches at the top.


Beaver dams are created as a protection against predators, such as coyotes, wolves and bears, and to provide easy access to food during winter. Beavers always work at night and are prolific builders, carrying mud and stones with their fore-paws and timber between their teeth.  Beavers are known for their natural trait of building dams on rivers and streams, and building their homes (known as "lodges") in the resulting pond. Beavers also build canals to float building materials that are difficult to haul over land.  They use powerful front teeth to cut trees and other plants that they use both for building and for food. In the absence of existing ponds, beavers must construct dams before building their lodges. First, they place vertical poles, then fill between the poles with a crisscross of horizontally placed branches. They fill in the gaps between the branches with a combination of weeds and mud until the dam impounds sufficient water to surround the lodge. 


https://en.wikipedia.org/wiki/Beaver



Beaver Lodge

Theodore Roosevelt National Park, North Dakota

March 28, 2020


The opening appears to be in the lower left and does not appear to be underwater.  This lodge was constructed in the fall of 2019 after the dam was built.


Beavers do not hibernate, but store sticks and logs in a pile in their ponds, eating the underbark. Some of the pile is generally above water and accumulates snow in the winter. This insulation of snow often keeps the water from freezing in and around the food pile, providing a location where beavers can breathe when outside their lodge.


https://en.wikipedia.org/wiki/Beaver


The ponds created by well-maintained dams help isolate the beavers' homes, which are called lodges. These are created from severed branches and mud. The beavers cover their lodges late each autumn with fresh mud, which freezes when frosts arrive. The mud becomes almost as hard as stone, thereby preventing wolves and wolverines from penetrating the lodge.  The lodge has underwater entrances, which makes entry nearly impossible for any other animal, although muskrats have been seen living inside beaver lodges with the beavers who made them.   Only a small amount of the lodge is actually used as a living area. Beavers dig out their dens with underwater entrances after they finish building the dams and lodge structures. There are typically two dens within the lodge, one for drying off after exiting the water and another, drier one, in which the family lives.  Beaver lodges are constructed with the same materials as the dams, with little order or regularity of structure. They seldom house more than four adults and six to eight juveniles. Some larger lodges have one or more partitions, but these are only posts of the main building left by the builders to support the roof. Usually, the dens have no connection with each other except by water.  When the ice breaks up in spring, beavers usually leave their lodges and roam until just before autumn, when they return to their old lodges and gather their winter stock of wood. They seldom begin to repair the lodges until the frost sets in, and rarely finish the outer coating until the cold becomes severe. When they erect a new lodge, they fell the wood early in summer but seldom begin building until nearly the end of August.


https://en.wikipedia.org/wiki/Beaver



Beaver Cutting

Theodore Roosevelt National Park, North Dakota

March 29, 2020



Beaver Evergreen Cutting

Theodore Roosevelt National Park, North Dakota

March 29, 2020



Beaver

Theodore Roosevelt National Park, North Dakota

March 28, 2020


Beavers are primarily active at night so photography can be difficult in low light conditions.



Beaver

Theodore Roosevelt National Park, North Dakota

March 28, 2020



Beaver

Theodore Roosevelt National Park, North Dakota

March 28, 2020



Beaver

Theodore Roosevelt National Park, North Dakota

March 28, 2020



Beaver

McLean County, North Dakota

April 25, 2020



Beaver

McLean County, North Dakota

April 25, 2020



Beaver

McLean County, North Dakota

April 25, 2020



Can you see the Beaver's Tongue?


Beaver

McLean County, North Dakota

April 25, 2020



Beaver

McLean County, North Dakota

April 25, 2020



Beaver

McLean County, North Dakota

April 25, 2020



Beaver

McLean County, North Dakota

April 25, 2020



Beaver

McLean County, North Dakota

April 25, 2020


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