Percentage of protein, lipids, and carbohydrates in the diet of badger ( Meles meles ) populations across Europe

Although originally evolved as predators, several species of mammalian carnivores exhibit a great trophic diversity, ranging from hypercarnivory to a high consumption of vegetable food. Habitat characteristics influence food availability and consequently could affect the nutritional composition of the diet of generalist species. By reviewing the available literature, we tested the hypothesis that intraspecific differences in the food habits of badgers ( Meles meles ) living in different habitats across Europe could affect the percentage of macronutrients (i.e., protein, lipids, and carbohydrates) in their diet. Notwithstanding the different composition of the diet, the percentage of protein and lipids fed by badgers did not vary among temperate forest‐pasture mosaics, Mediterranean woodlands, or scrublands and arable lands, suggesting a certain form of regulation of the diet balance. The percentage of carbohydrates was similar in the first two habitats, while it was fivefold higher in arable lands, where cereals were the main food of badgers and were consumed throughout the year. Earthworm consumption by badgers was positively related to the latitude, while the lack of any latitudinal or altitudinal pattern in protein consumption reflected the absence of a gradient in carnivory. A slight inverse latitudinal gradient in lipids consumption probably depended on the use, in southern Europe, of vegetal foods rich in lipids. We hypothesize that in agricultural landscapes dominated by crop cultivations, the decline of animal prey (i.e., earthworms, insects, and vertebrates) due to habitat loss forced badgers to increase the percentage of protein in their diet by over‐eating cereals, with the consequence of a disproportionate increase in carbohydrate consumption.