The local transient Killer Whales, the coastal ones, feed on Risso’s Dolphins. They’re kind of similar to a pilot whale. They’re up to 12ft long, they’re grayish white. They have a round shaped head, they don’t have the long beaks. Their head is similar to a pilot whale and they have a lot of scratch marks on them from the squid.
So they are one of the most frequent dolphins we see here because of the deep water here and also because there’s lots of squid here. But there was one day and this was again about 20 years ago and it hasn’t happened since. But the killer whales here, like I said, have never been seen preying on the Risso’s dolphins. We have seen the Outer coast transients, the ones that feed on the sperm whales. And they’ve caught Risso’s dolphins twice.
But the story was that the local transients we were watching and then all of a sudden this group of about 15 Risso’ dolphins came charging over and caused the group of transients to flee. It was like a reverse thing. So these Risso’s dolphins were chasing and pursuing this group of like 7 transient mammal hunting killer whales, which you wouldn’t expect because you would think the killer whales would be the aggressive mammal hunting whales.
And the Risso’s chased them for about like 15, 20 minutes. And they were all porpoising, going at a very high rate, swimming out of the water. And eventually the Risso’s kind of caught up to them and surrounded them and then everybody stopped. It’s like the Risso’s caught them into almost like a net because the Rissos surrounded them and I felt, felt like they put a net around them. It was like that they had surrounded them. So the killer whales were stopped completely in the water.
And they were going so fast it was hard for us to keep up on them on the boat. But they trapped these killer whales in the ocean, by surrounding for maybe 10 minutes or so. And then the killer whales broke loose and started fleeing again. And then a second time the Risso’s caught up and trapped them. And then eventually the killer whales, got away again and the Risso’s gave up. But it’s kind of reversed to what you would expect, dolphins to be chasing and attacking a killer whale and the killer whales to be so frightened by them.
So that was a really interesting story that I really always remember and think it’s pretty cool.
-Nancy
This post was adapted from a voice recording in episode 93 of the Whale Tales Podcast, listen here
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