Orcas and dolphins were seen off of B.C.’s coast together for the first time in what researchers are calling a “surprising alliance.”
The paper, which was published in Scientific Reports, reveals that the ocean’s two top predators were hunting for Chinook salmon together in the first video of its kind.
Involved in the hunt were northern resident killer whales and Pacific white-sided dolphins.
The study was done by researchers from UBC, Dalhousie University, the Leibniz Institute and the Hakai Institute and suggests that these interactions weren’t just by chance.
“Instead, the species appear to be working together to hunt Chinook salmon in waters off B.C., where they are often seen within metres of each other. ”
The collaboration is quite in-depth and intentional, as the study reveals.
“We also recorded reduced echolocation and rolling movements by the killer whales in the presence of dolphins, suggesting that the whales may eavesdrop on dolphin echolocations to scan broader areas to locate large Chinook salmon—prey that are too big for the dolphins to capture and swallow whole,” the paper states.
“We’ve long known that resident killer whales interact with Pacific white-sided dolphins, but seeing them dive and hunt in sync with dolphins completely changes our understanding of what those encounters mean,” said lead author Dr. Sarah Fortune, Canadian Wildlife Federation Chair in Large Whale Conservation and assistant professor in Dalhousie’s oceanography department.
University of British Columbia (A.Trites), Dalhousie University (S. Fortune), Hakai Institute (K. Holmes), Leibniz Institute for Zoo and Wildlife Research (X. Cheng)
“Our footage shows that killer whales and dolphins may actually be cooperating to find and share prey—something never before documented in this population.”
University of British Columbia (A.Trites), Dalhousie University (S. Fortune), Hakai Institute (K. Holmes), Leibniz Institute for Zoo and Wildlife Research (X. Cheng)
This drone footage shows off some of the intense action in the collaborative hunt. It sounds like very little goes to waste in these sorts of hunts.
“Captured fish were brought to the surface by the killer whales and broken apart for sharing with other matrilineally related pod members—while the accompanying dolphins scavenged scraps.”
University of British Columbia (A.Trites), Dalhousie University (S. Fortune), Hakai Institute (K. Holmes), Leibniz Institute for Zoo and Wildlife Research (X. Cheng)
Neither the B.C. orcas nor dolphins showed signs of aggression or avoidant behaviour toward one another.
“The findings highlight the ecological significance of interspecies associations and the potential role they play in shaping marine food webs and helping predators adapt in a changing ocean. The researchers say further investigation is needed to understand how widespread and consistent such co-operative behaviours may be.”
The study says that these findings will change the way researchers think about the relationship between the ocean’s two top predators.
You can read more on the UBC website.