A Wolf’s First Year By Jenny Golding
At a pullout along the road near Slough Creek, all eyes are trained on a wolf den far across the valley. It’s mid-May, and a group of wildlife watchers and researchers waits with anticipation for the first blue-eyed Yellowstone wolf pups to peek their heads out.
around them. Their aunts, uncles, older brothers, and sisters are vigilant protectors, ushering hapless bears or other animals away from the den. They are also patient playmates, tolerating the biting, pulling, and pouncing of the growing pups.
There’s one! An electric current passes through the crowd as a tiny ball of fur wobbles onto the mound of dirt at the mouth of the den. Then another, and another! At three weeks old, the pups are a sight to see: uncoordinated balls of fur, tumbling and falling all over the den area and each other, scarcely resembling the agile predators they will become.
Wolf mating and denning seasons set in motion fundamental changes to the behavior and physiology of a wolf pack. In February, wolf howls echo across the frozen landscape as alpha pairs (and other interlopers) initiate the next generation of wolves. As the alpha female settles on a den site in April—excavated in a steep hillside, under tree roots, or in a rock cave—she gives birth to four to five wolf pups. The hormone prolactin (the same hormone that helps bond human parents to their newborn) increases in each pack member, preparing them for the rigors of rearing pups.
Most dens are tucked far out of sight—wolves prefer to den several miles from people, and other packs. But sometimes in the wide-open expanses of Yellowstone, a den is visible from the road, giving visitors the rare opportunity to view wild wolf pups and the adults who care for them.
Once pups arrive, wolf life centers around the den. The once-abundant howls give way to a conspicuous silence: the wolves vocalize less often, in part to keep the location of the den hidden from rival wolf packs who might attack and kill the newborns.
Some 100 wolves roam Yellowstone National Park, thanks to successful efforts to restore the population in 1995. The raising of pups is an important part of the wolf lifecycle, and critical to the long term survival of a pack.
Making it to adulthood as a wolf in Yellowstone isn’t easy. On average three pups, or 55–65 percent of those born, survive their first year. In years where disease strikes, or rival wolf packs attack, pup survival can be as low as 10–20 percent.
Although the pups still nurse exclusively and sleep in the den, within a few weeks they begin to explore the world 6
