International Beaver Day – a celebration of nature’s engineers

International Beaver Day is a special celebration dedicated to animals whose activities shape the landscape more than many humans do. With their dams, beavers regulate water circulation, support biodiversity, and play an important role in mitigating the effects of climate change. April 7 is a great opportunity to learn more about these creatures, which Wanda Chotomska humorously described: Beavers don’t say: Good morning! Beavers say: Good beavering!

International Beaver Day – a tribute to Dorothy Richards

April 7 is no random date. It marks the birthday of Dorothy Richards (1894–1985), an American researcher who devoted her life to observing and protecting these remarkable animals. It all began in 1935, when two beavers were released near her home in New York State. Soon after, a dam appeared on the nearby stream, and Richards began to explore the mysteries of their lives. For over 50 years, she conducted research, established a 900-hectare reserve, and convinced the world of the key role beavers play in ecosystems. Thanks to her, in 2009, the organization Beavers: Wetlands & Wildlife established this holiday to draw attention to the need to protect beavers and their habitats.

In Poland, the celebration has special significance, as the history of beavers in the country is one of downfall and triumphant return. In the Middle Ages, they were valued for their fur and meat, and their population was large. However, in the 19th century, due to hunting and habitat destruction, they nearly went extinct. After World War II, only a few small populations remained in Poland, mainly in the Masurian region. A breakthrough came in the 20th century with reintroduction efforts – in Greater Poland, Professor Ryszard Graczyk played a key role by developing methods for bringing beavers back to their former territories.

Today, the European beaver is under partial protection in Poland (since 1952) and is covered by international legal acts such as the Bern Convention. Their population is growing (according to Statistics Poland, there are 149,900 beavers in the country), but their activities are also controversial – their dams sometimes cause flooding of farmland.

The European beaver – a closer look at our native beaver

The European beaver (Castor fiber) is a true giant among rodents. An adult can weigh between 15 and 30 kg, and its body, including the tail, can reach up to 140 cm in length. What are its distinctive features? Powerful, ever-growing incisors coated with orange enamel, capable of felling trees up to a meter in diameter, and a flat, scaly tail – referred to in hunting jargon as a “splash” or “trowel” – which acts as a rudder and an alarm signal in case of danger.

Their bodies are perfectly adapted to life in water: webbed hind feet make them excellent swimmers, and their eyes, ears, and nostrils are located high on the head, allowing them to observe their surroundings while barely emerging from the water. They can stay underwater for up to 15 minutes, and during dives, their eyes are protected by a transparent third eyelid. These are true masters of adaptation, equally at home on land and in aquatic environments.

Beavers are herbivores, and their diet is a feast of riparian delicacies. In summer, they enjoy aquatic plants and the bark of young twigs; in winter, they feed on the cambium of deciduous trees, which they store in underwater caches. Their powerful incisors grow continuously, so gnawing on trees is not only a way to gather building material but also a necessity – it helps wear down their teeth and keep them in shape.

Family life of beavers

Beavers are family-oriented animals – they live in small groups and work together on their constructions. They are active from dusk to dawn, which makes them difficult to spot. During the day, they hide in lodges – mounds made of branches, mud, and plants, with underwater entrances – or in burrows dug into the banks of rivers and lakes. These structures serve not only as homes but also as fortresses protecting them from predators.

There is no doubt, however, that the most recognizable creations of beavers are their dams. Built from trees, branches, mud, and stones, these structures can reach impressive sizes – the record-breaking dam in Canada stretches for 850 meters!

Why do beavers build dams?

Dams built by beavers are not a whim, but a condition for survival. They raise the water level, which enables the safe functioning of lodges and facilitates the transport of building materials. At the same time, they benefit the environment by increasing water retention, filtering water, and reducing the outflow of nutrients. Studies have shown that beaver structures slow river flow and stabilize hydrological conditions. In practice, they perform functions that would cost millions in water management – and they do it completely free of charge.

main photo: SteveRaubenstine / pixabay