Wolves in the Netherlands feed mostly on wild game, not sheep, study finds
Wolves in the Netherlands primarily feed on wild game such as wild boar, roe deer, and red deer, while sheep make up only a small portion of their diet, according to new research based on wolf scat collected in Drenthe and on the Veluwe.
The study, led by the Center for Environmental Sciences at Leiden University in collaboration with Stichting Leo, the University of Antwerp, and the Dutch Mammal Society, analyzed more than 700 wolf droppings collected in 2023. Researchers examined the remains of prey animals to determine the wolves’ diet and found strong regional differences based on available prey.
On the Veluwe, wild boar were present in 59 percent of the samples, red deer in 18 percent, and roe deer in 16 percent. In Drenthe, where wild boar and red deer are scarce, roe deer were found in 53 percent of the droppings, followed by free-ranging cattle used for land management in 37 percent, and sheep in only 6 percent.
The relatively small presence of sheep in the droppings surprised researchers. “That sheep are not a larger part of the wolf’s diet is surprising,” Glenn Lelieveld, a wolf expert and one of the study’s researchers, told NOS. He pointed to the high number of reported sheep attacks and offered several possible explanations.
“Wolves may kill more sheep than they actually eat,” Lelieveld explained to NOS. “Sheep often don’t flee, which may lead wolves to kill several animals in one go, sometimes leaving them behind. It's also possible that the wolves are disturbed during the attack and abandon the prey.”
Researchers also noted that free-roaming adolescent wolves, which are still searching for their own territory, may be responsible for some attacks. These young wolves do not mark their territory with feces in the same way as established wolf packs, making their droppings harder to locate and analyze.
Territory-marking behavior plays a key role in data collection. Wolves that live in packs typically use droppings to mark their territory, which makes their feces easier to find. Lone wolves scatter their droppings across the landscape, making detection more difficult.
The diet data was determined in two ways: through DNA analysis and through examination of undigested remains such as hair, feathers, bones, and other prey fragments. These remains help estimate the share of each prey species by biomass, giving a more accurate picture of what wolves primarily live on. DNA analysis, on the other hand, provides insight into the variety in their diet. For instance, researchers found that wolves also consume small birds like the blue tit and even fruit.
The research is focused on seven wolf packs—five on the Veluwe and two in Drenthe. The pack in Nationaal Park De Hoge Veluwe was excluded because researchers were not granted access to the park.
Lelieveld emphasized the significance of wild hoofed animals in wolf ecology and suggested regional wildlife policy adjustments. “Maybe we should revisit the idea of allowing more wild hoofed animals in Drenthe,” he told NOS. “In Drenthe, wolves eat more sheep and a lot more cattle than on the Veluwe, even though similar livestock is present in both areas. The main difference is the number of wild hoofed animals like red deer, fallow deer, and wild boar.”
He added that international studies have shown that a healthy population of wild prey animals helps protect livestock from wolf predation. “That seems like a good reason to start a conversation,” he added.
