Stalking the Forests and Swimming in the Oceans: Trophic Flexibility in Alaskan Coastal Grey Wolves

Stalking the Forests and Swimming in the Oceans: Trophic Flexibility in Alaskan Coastal Grey Wolves

Alvin Sherman Library

Coastal grey wolves of Southeast Alaska (Canis lupus ligoni) are opportunistic apex predators endemic to their environments. Large terrestrial vertebrates such as deer and marine organisms such as salmon dominate their diet. Large terrestrial vertebrates such as deer and marine organisms such as salmon dominate their diet. In recent years, wolves from Gustavus have moved back and forth between the mainland coastal environment and Pleasant Island, a small island 10 kilometers offshore. Wolves initially foraged on the island deer but more recently, a group of wolves has remained full-time on the island to forage on a marine diet including salmon, sea otters, and harbor seals from the nearshore shallow water environment. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios of the wolf hair and prey demonstrate distinct isotopic division from the herbivorous terrestrial prey (δ¹³C: -28 to -26‰, δ¹⁵N: 0 to 3‰) and the omnivorous marine prey (δ¹³C: -21 to -18‰, δ¹⁵N: 7 to 10‰) to the carnivorous wolf signatures (δ¹³C: -18 to -12‰, δ¹⁵N: 10 to 18‰). This unique trophic behavior in the mountainous coastal environment of Alaska may not be so unique elsewhere in the Pacific Northwest. One thousand kilometers to the south, the British Columbia coastal grey wolf, also known as the Vancouver sea wolf, forages primarily on marine organisms with little to no terrestrial input, though they are abundant in the area. Although these wolves share a similar diet and habitat, these mammals are genetically different. By observing trophic changes in coastal grey wolves, scientists may better understand how environmental fluctuations can influence the opportunistic foraging behavior of these wolves.