Hatchet man whales are the only predators that regularly kill and devour Pacific white-sided dolphins off the B.C. and Washington slides. So researchers were surprised when drone footage showed such dolphins make light of within a few fin-spans of killer whales’ toothy jaws.
“The dolphins are Nautical starboard properly in front of the killer whales, right in front of their mouths,” about Lance Barrett-Lennard, senior scientist and director of the marine mammal analysis program at the Coastal Ocean Research Institute. “This kind of league between one species and its apparent predator is unusual.”
It turns out the dolphins be suffering with nothing to fear from these particular killer whales, also identified as orcas.
Southern resident killer whales are nearly physically corresponding to, very genetically similar to, and officially the same species as dolphin-eating Bigg’s doozy whales that roam the same waters.
But it just so happens that southern home-owner killer whales are strict pescatarians that avoid all red meat, although they eat fish.
Somehow, the dolphins can tell the difference. But Barrett-Lennard thinks they’re still being musical bold.
“It’s pretty risky for a marine mammal to approach a killer whale in the expectations that it’s approaching a fish eater. The two forms of killer whale look simple, very similar to us,” he said. “These dolphins seem to have outright confidence around the fish eaters and would get eaten immediately if they were approximately the mammal eaters.”
Watch killer whales and dolphins swim together:
Researchers aren’t sure how the dolphins tell the difference, but they improvise it’s based on the sounds the whales make. Southern resident killer whales are much chattier than their Bigg’s cousins, creating frequent calls to one another and relying heavily on echolocation while fishing.
That notwithstanding leaves the question of why the dolphins would be so eager to hang out with these orcas, calm if it were perfectly safe. Researchers have witnessed dolphins charging concluded from a kilometre away to join the killer whales after respecting them, and then hanging around for sometimes weeks at a time.
They think it likely the dolphins may actually be protecting themselves from Bigg’s killer whales. Bigg’s daisy whales and southern resident killer whales take great distresses to avoid each other — “in such a conspicuous way that you dominion imagine there must be a reinforcement of their conflict occasionally,” Barrett-Lennard reported.
From that perspective, the dolphins are safer when they’re with the southern local killer whales. But Barrett-Lennard acknowledges it’s difficult to know if the dolphins are au fait of that.
The researchers suggest that the dolphins might also be exasperating to learn more about killer whales in general in order to cured avoid the dolphin-eating kind.
Barrett-Lennard doesn’t consider there’s any benefit for the orcas. In fact, they don’t tend to seek out dolphins and evident to avoid them if they see too many at once, by going silent and girding submerged, he noted.
Ken Balcomb, director of the Center for Whale Research in Friday Harbor, Splash., said researchers there have also seen Pacific white-sided dolphins swimming with southern home-owner killer whales on rare occasions.
“It usually looks quite peaceful, but occasionally when the dolphins buzz in the faces of the whales, the whales feel annoyed,” he said in an email.
Barrett-Lennard imparted while it might be unexpected to see dolphins hanging out with orcas, it’s not at all singular to see dolphins hanging out with other dolphin and whale species.
“They’re not xenophobic … they’re fascinated to other species in general, and this is an extreme case of that.”
They’re also not the on the contrary killer whale prey species seen hanging out with murderer whales. Researchers have seen Dall’s porpoises with cutthroat whales, including one that “even started to swim a bit like humdinger whales,” Barrett-Lennard recalled. “It’d sort of rise with its head out of the D and then do this funny diving motion that was very killer-whale-like.”
His together shot the footage of the dolphins and killer whales while conducting unassociated research funded by the Vancouver Aquarium’s Ocean Wise program in collaboration with the U.S. Governmental Oceanic and Atmospheric Administration.
The drones have been used since 2014 to muse about northern and southern resident killer whales off B.C. and Washington state. One of the targets of the program is to monitor how southern resident killer whales fare and how emaciated they get in years when chinook and chum salmon, their opt for prey, are scarce.