Thu February 14, 2013
With Brawls And Calls, Love Is In The Air For Elephant Seals
On this Valentine's Day, we bring you a story from the California coast, where love is in the air. It sounds something like this:
That's a male northern elephant seal. It's the peak of their mating season right now. Elephant seals spend of the most of the year alone, out in the Pacific Ocean. So you can probably guess what happens when they get together every winter.
Naturalist Lisa Wolfklain is leading a public tour at Ano Nuevo State Reserve, two hours south of San Francisco, where hundreds of elephant seals are packed together on a narrow strip of beach.
Male elephant seals are the size of an SUV — 15 feet long and 4,000 pounds — with a huge, fleshy nose. There are plenty of females here, but most of these males will strike out. The dating scene is controlled by alpha males.
"The alphas' strategy is to be dominant over a group of females, the harem," Wolfklain says.
You can see the alphas right in the middle of these harems — some with up to a hundred females. The rest of the males — the betas — are on the outskirts, watching, waiting for their chance.
One beta male has decided this is his moment. He moves quickly toward a female, and the alpha male perks up.
"Ooh, now they're hitting with their heads," Wolfklain says.
A few strikes seem to be enough.
"Now he turned around and ran," she says.
These fights can get bloody, and all the while, other beta males are making their move.
"It's not advantageous for males to fight all the time," says Caroline Casey, a researcher at the University of California, Santa Cruz. She says that because these fights can be fatal, males try to avoid them by talking tough. But no one was really sure what they were saying, so Casey and her colleagues tracked 50 males and recorded their calls — like this one, a male named X579.
"His call to me is my favorite," Casey says. "He always has this really lovely note at the end of it."
X579 was a beta male with a lot of competition.
"He tends to vocalize and challenge everybody right when he gets there," she says. He challenged an alpha named GL, who responded ...
"His call was very short, very to the point," Casey says. "That is what's so incredible. All of the animals sound completely different from one another."
Casey says they've found that each male uses the same call year after year, whether he has a harem or not. It's their signature call — and they flaunt it.
"A larger, more dominant animal will come up to an animal, a smaller animal, maybe beat him up a little bit, call at him before and after, be like, 'Hey, this is me. I'm Bob. Don't mess with me,' " she says.
It's all about spreading your reputation around, she says.
"That's called associative learning, and that's very unique among marine mammals," Casey says. "That means that every male has the potential to be learning every other male based on their acoustic signature at that site."
Casey says these complex communication systems have been studied in songbirds and other animals, but less is known about elephant seals.
"I think it's just a piece of a larger puzzle in understanding kind of how these animals breed, and ultimately how they're going to survive," she says.
Elephant seals were hunted to near extinction for their blubber a century ago. With protective laws in place, today there are 170,000 northern elephant seals on the West Coast, and that number is growing.
That's good news for loner male X579. This year, he's an alpha for the first time. For most of the other male elephant seals, there's always next year.