Field Notes: a Northwest nature blog
One of the reasons many of us live in the Pacific Northwest is the natural wonders that amaze us all. On this blog Seattle Times writers and photographers will share their explorations of the natural world from snowcaps to whitecaps. Write us at email@example.com with your own sightings, questions and wonders to share.
With the oldest male whale, "Ruffles," gone, who will be orcas' next Big Daddy?
Posted by Craig Welch
He was the first southern resident killer whale in J-pod to be identified, perhaps because he was so easy to distinguish from the others.
J1 came to be known by many as "Ruffles" because his dorsal fin was wavy, like a potato chip, or a flag in the wind.
When he disappeared sometime last fall, killer whale experts and orca watchers knew the score; J1 was nearly 60 years old. They wrote rememberances, set up social networking pages and put up photo galleries. The Big Daddy of the southern residents almost certainly had died.
But J1's absence is raising interesting new questions about how the makeup of the southern residents will change now that he's gone. His death is yet another reminder that even though Puget Sound's orcas are among the most studied marine mammals in the world, much about them remains a mystery.
A recent study surprised some of the region's top orca experts when it revealed that the southern residents were inbreeding. Males and females were reproducing within the same pod, which gives scientists a new cause for concern. It appeared that only a handful of males were responsible for many of the offspring. Chief among them: Ruffles, who had sired at least eight calves, five of them with females from J-pod.
Did that mean there was something about Ruffles that attracted female whales? Did they choose to mate with him simply because, having been born in 1951, he was by far the most senior male? Was J1 outcompeting the many other younger males? Or were they showing deference to him as their social leader? Is there an important difference in orca culture between sexual maturity and social maturity?
"The truth is, we don't really understand their breeding structure all that well," said Brad Hanson, a biologist with the National Marine Fisheries Service's Northwest Fisheries Science Center in Seattle. "If you had male-male competition, you might expect to see more scarring on them from fighting, but we don't see that, at least not to the extent that we see it with other species."
Or perhaps killer whales are more like Dall's porpoises, which don't fight so much as simply push each other around. Then again, porpoises don't really have the jaws and teeth for fighting. Killer whales do.
What's clear, though, is something new is certain to emerge. Orcas reach sexual maturity at about 15 years of age. And before J1's death, the next eldest male was L41, who is several decades younger, in his 30s.
"With J1 going on, there's sort of a regime-shift taking place, if you will," Hanson said. "It will be interesting to see who fills in the gap. Is it just going to be L41? Or is it going to be some of the younger animals? We don't know.
"What we know is that this is a relatively major change," he said.
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