REGIONAL— As anyone who has brought their canine companion on an afternoon of blueberry picking knows well, dogs like blueberries. And, as a new study by researchers with the Voyageurs Wolf Study confirms, the same is true of your dog’s wild cousins.
Not only do wolves eat blueberries, some wolves eat a lot of berries in July and August, which is generally peak season for wild fruits in the North Country. And that’s not the only surprising detail in the research team’s latest publication in the journal Biology Letters. It turns out that blueberries benefit as well, as the study found that germination rates for blueberry seeds were improved by as much as 27 percent from passing through a wolf’s gut. It points, once again, to the often mutually beneficial relationships commonly found in the natural world.
Through their ongoing work, researchers with the Voyageurs Wolf Project have documented the extent to which wolves will turn to blueberries as a summer food source when berry crops are abundant. “During peak berry season (July–August) in the [Greater Voyageur Ecosystem], berries constitute up to 83 percent of weekly diets of adult wolves and over 30 percent of pup diets,” the research team wrote in their study. They also documented that wolves consume wild raspberries when in season.
But the most notable finding was that consumption by wolves improved the germination rate of blueberry seeds and that wolves served as an important means of seed dispersal through their droppings.
As part of their study, researchers recovered 802 blueberry seeds from wolf scats in their research area. They tested their germination rate against a control sample of 484 blueberry seeds that were harvested directly from hand-picked berries. They found that the berries that passed through wolf guts experienced a 96 percent germination rate compared to 69 percent for the control sample. In addition, researchers found that the seeds that passed through wolf guts germinated an average of seven days sooner than the control sample.
The researchers did note that germination rates among the seeds in the control samples were highly variable, ranging from 91 percent to 42 percent. Even using the highest germination rate among the seeds in the control sample, researchers noted that the germination rates for seeds consumed by wolves were at least five percent more likely to germinate.
The researchers surmised that berry seeds that passed through a wolf’s gut experienced either physical or chemical scarification, which made the seed more responsive to conditions favorable to germination.
In the publication of their findings, the research team included maps of GPS locations of three wolves from July 10-Aug. 16, 2024, which showed the wolves that travel between berry patches dominated their active hours during the peak of the berry season.
“Our findings detail another way wolves are connected to larger ecological processes in boreal ecosystems,” concluded the research teams. “Through the simple act of consuming blueberries, wolves may facilitate the propagation of blueberry plants by dispersing blueberry seeds, which have higher probabilities of germinating, across large areas. Wolves regularly travel long distances, can make large daily movements and therefore could be meaningful dispersers of seeds beyond local distribution.