KNOWLEDGE BASE

Researchers studied the stomach contents of wolves in Latvia, finding beavers in 9% of the samples. Beaver remains were more likely to be found in the stomachs of male (13%) rather than female (3%) wolves. This aligns with findings from other studies, and can be explained by the fact that wolves hunt beavers alone and male wolves wander around alone more than female wolves, especially when looking after baby wolves.

Beavers like feeding on willow trees. This study tried to work out what the impact of this behaviour is on willow communities by using a simulation model based on a National Park in the USA. The model shows that beavers make willow trees grow faster and make the community more diverse, with a mix of younger and older plants. The total mass of willow is kept lower on average. This, ultimately, is beneficial for the ecosystem.

This text examines how tooth size varies with age in two beaver species, Castor fiber and Castor canadensis. Measurements reveal significant size differences, especially in incisors, premolars, and third molars. The teeth often keep growing until the beavers are around 50 months old, then mostly stop growing. Comparisons with fossil beaver species show similar size ranges. The text also compares these results wiht fossil beavers and finds similar results. However, determining beavers' age based on the shape and physical features of the tooth is challenging.

Researchers studied how beaver dams and autumn rains affect Atlantic salmon spawning. Most dams didn't affect spawning but some did - the use of 'notching' helped salmon to make it through dams when they did block salmon migration. Heavier rains helped salmon to access more of the stream (especially when beaver dams did block their passage).

This report was commissioned by Natural England to help them understand whether beavers should be reintroduced to the wild in Britain. The report concludes by saying that reintroduction is feasible, likely beneficial, that negative impacts are likely manageable, and recommends necessary next steps including public education. Within the main text, the authors explore many aspects of beavers' biology, ecology, behaviour, and socio-economic impacts.