KNOWLEDGE BASE

This paper compared skulls of 2 ancient beavers with those of modern beavers in Poland. It found that ancient beavers had notably larger skulls than modern beavers of the same age. This is precisely set out by measuring different parts of the skull, including a part called the sagittal crest. Tables 3 and 4 set out these results in comparison to modern beavers.

Castoreum extract is a natural substance derived from beaver scent glands. This article assembles the research on its toxicity as a food additive. Based on the limited current data, consuming castoreum extract at current levels is deemed safe. Its long-term use throughout history without reported adverse effects supports this conclusion. It is regarded as safe by regulatory bodies. Overall, using castoreum extract at current levels poses no safety concerns. Please note, this resource is not open-access.

This study found that beaver ponds are vital for boreal chorus frogs, wood frogs, and western toads - none of these amphibians were found on streams without beaver dams. The authors used mapping software to analyse where beaver dams were likely to be built. Doing a similar analysis over a larger mapped area could be a quick way of finding good spots for amphibian monitoring. Overall, the authors suggest that amphibian conservation could benefit from forest management strategies taking beavers' dam building into consideration.

The return of beavers to a National Park in the USA has led to an 89% increase in wetland habitats between 1944 and 1997. Beavers had converted forested areas to open water and wetlands, benefiting pond-breeding amphibians by providing more breeding sites. Beavers initially favoured larger, lower sites, but later on, beaver sites were smaller and higher up the river. Many were abandoned, creating a diverse habitat mosaic. Please note, this resource is not open-access.

One challenge of managing conflicts between humans and beavers is the fact that people's views vary and change over time. In the USA, after a law was passed banning certain beaver traps, surveys were carried out to understand public opinion. This article reports on these surveys. Overall, people had positive views of beavers but those who had had negative experiences with beavers held less favourable views. The authors suggest that conservation efforts should be responsive to changing public attitudes. Please note, this resource is not open-access.