Wolves on the Alaskan coast now often kill and eat sea otters and harbor seals, scientists have found.
The discovering means that the coastal wolves can adapt their looking habits — and will have developed distinctive methods to prey on marine mammals when meals on land is scarce.
The examine into coastal wolf looking behaviour started in 2016 when scientists noticed a solitary wolf carrying a sea otter carcass at Swikshak Bay.
In 2018 and 2019, scientists once more noticed wolves carrying sea otter carcasses. Nevertheless, whether or not the wolves have been looking or scavenging was unclear.
Then in 2021, three wolves (Canis lupis) have been noticed looking and consuming an grownup sea otter (Enhydra lutris) throughout low tide.
The researchers examined the kill web site and located a pool of blood the place the ocean otter was doubtless killed.
In response to the examine, printed Oct. 31 within the journal Ecology, the presence of blood signifies the ocean otter had been alive when ambushed by the wolves, versus being scavenged which might not produce recent blood pooling.
The findings counsel coastal wolves in Katmai might focus their looking efforts at websites the place prey is most predictable, equivalent to tidal streams or rocky islands. The workforce additionally discovered that wolf predation coincided with low tide cycles — indicating they’d developed an consciousness of the place and when the ocean otters have been spending time on land.
“We have now seen that coastal wolves typically hunt alone or in partial packs and that particular person wolves and packs might have completely different looking methods or goal sure prey relying on the place they’re,” Kelsey Griffin, lead writer of the examine and Nationwide Park Service wildlife biologist, instructed Stay Science. “It exhibits that wolves are an essential linkage between terrestrial and marine ecosystems. This examine reframes how we take into consideration wolves — it exhibits they’re not simply terrestrial.”
Researchers have been monitoring the rising pattern of wolves looking marine prey on Alaska’s Katmai Coast since 2015. Their newest analysis builds on a examine printed earlier this 12 months within the journal PNAS that exposed wolves on Nice Island have been looking and killing sea otters as a major meals supply after eradicating the deer inhabitants.
“That is actually thrilling documentation of behaviors we consider have by no means been immediately noticed by scientists,” Ellen Dymit, a doctoral scholar at Oregon State College, mentioned in an announcement. “It sort of forces us to rethink the assumptions that underlie a whole lot of our administration choices and modeling round wolf populations and populations of their prey, which frequently assume that wolves rely on ungulates, like moose and elk.”
In future work, the scientists wish to develop their research to research the habits of wolves from Lake Clark Nationwide Park, Glacier Bay Nationwide Park and Kenai Fjords Nationwide Park.
“Wolves are extremely smart so it is sensible they’d adapt, though the solitary wolf looking habits we’re seeing are distinctive to coastal wolves,” Griffin mentioned. “Along with a extra numerous prey base, it’s distinctive in {that a} single wolf was profitable in taking down giant prey equivalent to a harbor seal in comparison with inside wolf exercise which generally includes a pack effort to kill ungulates equivalent to moose.”
Researchers now plan to discover how sea otter density impacts the diets of wolves on a person and pack degree.
“By way of how wolves might change the nearshore ecosystem, additional examine is required,” mentioned Griffin.
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This article by Carys Matthews was first printed by Stay Science on 7 November 2023. Lead Picture: Wolves (Canis lupis) have been noticed looking sea otters alongside Alaska’s coast since 2016. (Picture credit score: Landon Bazeley/Kelsey Griffin).
