Researchers have recorded video evidence of wolves in British Columbia using crab trap lines to pull the traps out of the ocean to feast on the contents, further substantiating long-held theories about the intelligence of the species.
The traps were being used near Bella Bella on the central coast of B.C. to manage the invasive European green crab. Some of these traps were consistently submerged in deeper waters, prompting researchers to conclude that the damage that began in 2023 could be attributed to marine mammals.
They were soon proven wrong. Researchers managed to record footage of a female sea wolf coming out of the water with a buoy in her mouth, just one day after the cameras were set up last May.
The footage captured the wolf dropping the buoy onto the shore, retrieving the line, and tugging on it until the crab trap surfaced from the water. Next, the wolf used her mouth to pull the trap to the edge of the shore, chewed on the bait cup until it fell from its attached lid, and ate its contents.
Artelle, a researcher with State University of New York College of Environmental Science and Forestry, said the level of intelligence shown by the animal amazed researchers.
“We know that they’re really, really smart, but it hadn’t crossed our mind that maybe a wolf is swimming out to the deeper traps and bringing the buoy to shore, pulling the line up just like a person would,” he said.
The cameras later captured a second sea wolf also extracting a crab trap in a similar fashion earlier this year. The footage led researchers to theorize that other wolves in the local pack could be learning from each other.
Artelle said they can’t know for sure how the wolves learned to raid the traps or how many might be engaging in such behaviour. He suggested that a wolf might have initially spied the traps onshore during low tide, kickstarting a process of learning how to access them at different submersion depths. From there, the wolf could have linked the line to traps that were fully submerged and subsequently the buoy to the line, he said.
While there may have been some unsuccessful attempts early on, Artelle said, it was clear by the time the cameras were set up the wolves engaging in the behaviour had figured out a “really sophisticated” plan to access the traps.
Tool Use Among Wolves
The report Artelle penned with Paquet, a conservation science expert affiliated with the University of Victoria, explores the wolves’ tool use, a behaviour of using an external, unattached object to achieve a goal.The report indicated that tool use in this case extended beyond mere causal insight, suggesting that the wolves not only possessed a sophisticated understanding of the trap, but a more advanced level of cognition overall.
The researchers said they were unable to determine if this degree of advanced behaviour is more prevalent than previously thought, yet seldom recorded due to the elusive nature of non-captive wolves, or if it is a rarity.
They noted that it was difficult to determine if the preconditions for this behaviour are universally present among non-captive wolves or if they are more particular to wolves in this area, where there are relatively low levels of human interference.
“Reduced need for vigilance might allow wolves to develop confidence and devote time to exploring novel behaviours such as those observed in this study, which might be less expected in more persecuted populations,” the authors wrote.
A few cameras at the B.C. site to monitor the crab traps are now being used to observe the behaviour of sea wolves in the vicinity full-time, the researchers said.
Sea wolves are a subspecies of grey wolf that are endemic to the coast of B.C.’s Pacific Northwest. Officially known as the Vancouver Coastal sea wolf, the creatures swim between islands to hunt seafood, and inhabit areas that are largely free from human interference.
The species are strong long-distance swimmers and have a diet that is approximately 85 percent marine-based, but will also hunt moose and black-tailed deer.
