The ingenious beaver

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The beaver, Canada’s official emblem, which is engraved on our five cent pieces, is an engineer by nature and of nature. The dams it makes on streams and rivers model the surrounding landscape and promote biodiversity. These structures, unique in the animal world, allow the beaver to control the water level so as to have easy access to neighbouring trees and keep the entries to its den underwater.

In slowing the flow rate of streams, beaver dams reduce bank erosion, capture sediments and improve water quality. The reservoirs thus created, and the canals the beaver sometimes dig to access food sites, ensure the presence of water during droughts, irrigate the forest and reduce the risks of fire…in addition to allowing the beaver to make a quick getaway when danger threatens.

Beaver ponds attract a wide variety of insects, fish, amphibians, birds and mammals which benefit from the abundant vegetation and the animals it attracts. In cutting down the trees around these ponds and streams, the beaver thins out and regenerates the forest by promoting regrowth.

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The beaver lives in a structure built close to the river or resting on its bank. This shelter, or “lodge”, is typically a pile of branches and mud, in the middle of which the beaver creates a chamber a metre in diameter and 50 cm high.

It accesses its lodge via one or two entrances located underwater. It may also dig a burrow on the bank of a river or stream. The lodge houses the entire family: an adult couple, which are lifelong partners, the year old young and that year’s newborn kits.

To prepare for winter, the beaver covers its lodge with mud to insulate it and gathers a large quantity of branches for its food reserves. Some specific aspects of its morphology facilitate the work of North America’s largest rodent.

Its enormous incisors, which never stop growing, allow it to gnaw tree trunks and cut off the branches whose leaves, buds and inside bark make up the major part of its diet.

The agile clawed digits of its front paws help it to transport the stones, mud and wood with which it builds its homes and dam. It scaly tail, large and flat, is an efficient rudder which it sometimes uses to slap the water surface loudly prior to diving. Its rear paws, which are webbed, are used as paddles. The beaver can remain submerged for many minutes and gnaw underwater without suffocating. Its ears and nostrils have valvelike folds which close when the animal dives, preventing water from entering.

Vulnerable on land, the beaver fears the great predators – wolf, coyote, fox, bear and lynx – and is wary of humans, which have chased them practically forever. Its fur has, for a long time, been used to make hats and coats and played a central part in the development of the Canadian economy. In the 19th century, only drastic protective measures were successful in preventing the complete disappearance of the animal from our regions.

Now once again plentiful, the beaver often lives close to dwellings. To avoid potential damage, we can protect tree trunks with wire mesh and control the level of water in ponds using an appropriate system of pipes. The beaver is a must-see star at Animalium, Mont-Tremblant’s zoological museum.

 

By the same author: The intelligence of the raven (Click the image below)

 

Jacques Prescott83 Posts

Jacques Prescott est biologiste, professeur associé à la Chaire en éco-conseil de l’Université du Québec à Chicoutimi et co-fondateur de l’Animalium, le musée zoologique de Mont-Tremblant. Spécialiste de la biodiversité et du développement durable, il est l’auteur de nombreux livres et articles sur la faune et la conservation de la nature. Il nous fait l’honneur de rejoindre notre équipe de collaborateurs et signera chaque mois une chronique intitulée Faune et flore. / Jacques Prescott is a biologist, associate professor with the Chair in Eco-Counselling of the Université du Québec à Chicoutimi, and co-founder of Animalium, the zoological museum of Mont-Tremblant. A specialist in biodiversity and sustainable development, he is the author of numerous books and articles about wildlife and nature conservation. He has honoured us by joining our team of contributors and will write a monthly column entitled Wildlife and Habitat.

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