As an alternative narrative to the story of Little Red Riding Hood, Mendel University researchers are studying the diet of wolves. As a part of our series about research on environmental issues at MENDELU, Brno Daily’s Coline Béguet accompanied the researchers from the forest to their laboratory. In the previous episode, we followed the specialist in large predators Miroslav Kutal during his field work monitoring the presence of wolves in a Czech natural reservation, and today his colleague, zoologist Martin Dul’a, shows us around the laboratory at MENDELU. Illustration and photo credit: Coline Béguet / Brno Daily
The samples of wolf droppings collected during Kutal’s expeditions in the forest have been brought to the laboratory of the Mendel University Department of forest ecology and stored in large fridges to be analysed as part of a study on the diet of wolves. The wolf has returned to the Czech Republic after disappearing for a century, and is now a protected animal. This does not please everyone, especially cattle breeders whose animals are sometimes hunted by wolves for food. It is in this context that this study is trying to better understand the hunting and feeding habits of wolves, in the hope of finding future solutions to the difficulties of cohabitation between the agricultural world and wildlife.
A brand new FFP2 mask is offered to me as soon as I arrive at the laboratory, and I am explained the health safety rules to follow, such as wearing gloves and not touching my face. This is not about COVID 19, but about the risk of disease passing from wildlife to humans. Handling the excrement of wolves, like any wild animal, requires precautions if one does not want to end up with, for example, a charming tapeworm a few metres long who will accompany you everywhere for years. The warning works so well that I don’t touch anything other than my camera for the duration of my time there.
The first step is to “wash” the faeces. This term, which may seem slightly paradoxical, means that the excrement is rinsed, then passed through a fine sieve, in order to keep only the wolves diet residues such as hair or bone fragments from their prey. Indeed, wolves eat everything of their prey, and these elements are the ones that will allow the identification of the composition of the wolf’s meal. After this step, the samples are dried, then again carefully packed and numbered while waiting to be finally analysed.
Martin Dul’a, a specialist in large carnivore ecology, management and conservation, begins by simply observing each excrement with the naked eye to look for clues. Sometimes certain elements make it possible to immediately identify what the wolf had for dinner, such as a whole fawn’s hoof. On the other hand, when there are only hairs, the task is most of the time a little more difficult. With the naked eye, it is generally possible to know to which taxonomic group the animal that has been eaten belongs, but to be certain as to the exact species, for example a roe deer or a deer, it is necessary to observe the hairs under a microscope.
When enlarged, the hairs of each animal have a different structure, different microscopic patterns. This is how Dul’a and his colleagues can identify with near certainty the diet of the animals they study. However, some hairs may look the same, and it is sometimes necessary for several people to check to obtain reliable data. They make use of a book, always available on the laboratory table, which is a sort of dictionary of hairs, where those of each species are meticulously described and classified.
Each wolf has its own food habits, depending on hunting opportunities and perhaps also on gastronomic preferences, and therefore they do not follow the exact same diet. Today, our wolf had unusually eaten a hare, but their typical diet consists of an average percentage of approximately 95% of wild ungulates, such as wild boar, roe deer, deer or fallow deer. The remaining 5% are the smallest prey, such as rodents, those that cannot be formally identified, and rarely farm animals such as sheep. The share of the latter is smaller than expected, suggesting that, contrary to some public opinion, the wolf is indeed a wild animal that is part of an ecosystem and not a relic of the past surviving only at the expense of breeders.
Predators are necessary in an ecosystem because they preserve balance. First, when they hunt, they generally attack the weakest animals, which can be useful to limit the spread of diseases in those species and paradoxically save some lives. They also help regulate the population of their prey, which otherwise would become too abundant and weigh on the balance of nature. For example, if there are too many deer, young trees struggle to grow because the leaves are eaten as they grow. Finally, returning to agriculture, central Europe has a population of ungulates which tends to be overabundant, which poses a problem for silviculture, as well as agricultural plantations in food destinations. Therefore, even if they inflict damage to agriculture on the herds of cattle, the wolves provide an important service by limiting the ungulate population, which avoids costly damage on the plantations.
