Since arriving on Alaska’s Pleasant Island in 2013, a pack of wolves has nearly wiped out the island’s deer population and now feeds primarily on sea otters.
life
January 23, 2023
Wolves searching for prey on Alaska’s Pleasant Island Gretchen Loeffler/Bjorn Diehl
Having nearly wiped out the deer population on the Alaskan islands, wolves now get most of their food from sea otters and other marine life.
A diet of seafood seems to be a good fit for wolf packs, as wolf packs have reached one of the highest population densities ever recorded for this species.
This is believed to be the first case of sea otters (enhydra lutris) spends almost all of its time at sea, making it a major food source for terrestrial predators, said Taal Levi of Oregon State University in Corvallis. “Nobody would have predicted this.”
Wolf (canis lupus) were already known to eat sea otters and fish, but not as a primary food source.In 2013, two wolves were first sighted on Pleasant Island, swimming in from the mainland. Levi’s team has been studying them and their descendants since 2015.
That year, analysis of wolf poop on a deserted island suggested that deer made up about three-quarters of the diet, with sea otters making up the remainder.
However, deer numbers have declined rapidly. By 2017, the island was home to 13 wolves, while deer made up just 7% of his 2015 population.
A wolf above the low tide line dragging a dead sea otter at Cape Gustavus, Alaska Alaska Fish and Game Service.
In 2020 there were 8 wolves on the island. An analysis of the sea otter droppings showed that the sea otter made up 57% of his diet, with very little deer. The rest of their diet consisted of fish and other sea creatures.
Population densities reached 124 wolves per 1,000 square kilometers, although levels of about 25 per 1,000 square kilometers are more common in wolf habitat.
During a visit to one island, the researchers saw three wolves ambushing a sea otter that migrated to the shore. “Wolves know they’re not going back to sea,” he says. “It was a flanking attack.”
Sea otters may come ashore to avoid marine predators or because of storms at sea, he says.
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