KNOWLEDGE BASE

Researchers used computational analysis to see what geographic features influence North American beavers' damming in small streams in the USA. They divided streams into segments and analysed different geographic features including: slope of the stream, proximity to roads, and the size of the watershed feeding into each segment. Beavers preferred building dams near roads, with slopes of around 1%, and watersheds that were neither too big nor too small. Roads may slow down the flow of streams slightly, meaning that the beaver needs to spend less additional energy to build a functional dam.

This paper examined the structure of Eurasian beaver sperm and compared it to closely-related rodent species. The researchers used electron microscopy to do so. Beaver sperm typically has a paddle-shaped head and a shorter tail than other rodents. This structure differs significantly from other rodent groups, even those closely related. Beavers' sperm and testis structure is related to their monogamous nature. Please note, this resource is not open-access.

In this article, scientists studied whether man-made industrial chemicals could be found in animals such as fish, birds, and beavers. These chemicals are collectively called polyfluoroalkyl compounds and are found in many day-to-day materials and industrial products. They took liver samples from beavers in Poland and blood samples from several fish and bird species. All of the chemicals were found in the animals, but some animals had higher levels of specific chemicals than others. Please note, this resource is not open-access.

Wolf diets can be hard to study by traditional methods - their large range makes fecal samples hard to gather! In this study, researchers studied wolf diets by analysing the balance of carbon and nitrogen isotopes from two North American grey wolf populations. This is possible because these wolves' prey - moose and beaver - have different isotopic balances themselves. This analysis can help scientists understand wolves' eating habits today, but also to study ancient wolf diets from fossil records.

This article reviews the emerging field of reintroduction biology. It looked at 454 papers from 1990–2005 and found that most research on wildlife reintroductions was retrospective and opportunistic. Whilst documentation of outcomes had improved, there was potential to use experimental and modelling approaches to enhance success. The case of beaver reintroductions to Scotland and the Netherlands were given as positive examples of using modelling approaches to assess reintroduction viability.